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15 Commits

Author SHA1 Message Date
d6523fe463 bump to v0.4.7 2015-02-10 15:59:33 -08:00
c25127a699 Merge pull request #2262 from yichengq/047
server: forbid /v2/stats/leader on follower
2015-02-09 22:29:48 -08:00
9f031e6218 server: forbid /v2/stats/leader on follower 2015-02-09 14:50:34 -08:00
e55724e959 Merge pull request #2260 from yichengq/047
server: refresh commit index when someone rejoins
2015-02-09 14:35:00 -08:00
29af192e3d server: refresh commit index when someone rejoins
Update commit index when rejoin happens, because 2.0 doesn't accept
more than one uncommitted config entry.
2015-02-09 14:28:30 -08:00
2fc79912c2 Merge pull request #2194 from yichengq/o3
server: standby exits when detecting v2 is running
2015-01-30 09:32:19 -08:00
ebb8d781b5 server: standby exits when detecting v2 is running 2015-01-29 16:26:47 -08:00
2e30b3c17f Merge pull request #2130 from xiang90/047-version
server: add internal version
2015-01-22 15:23:38 -08:00
9a2d82854e server: add internal version 2015-01-22 15:23:15 -08:00
b077dcf6c4 Merge pull request #2125 from xiang90/047-handler
next-version-handler
2015-01-22 11:40:54 -08:00
2b572cb6e8 Merge pull request #2126 from yichengq/o1
etcd: register usable versions when bootstrap
2015-01-22 11:32:23 -08:00
f36d55f062 next-version-handler 2015-01-22 11:20:52 -08:00
9f70568a02 etcd: register usable versions when bootstrap 2015-01-22 11:08:58 -08:00
1ca7d1e064 Merge pull request #2124 from xiang90/047-version
server: add version monitoring
2015-01-22 10:38:27 -08:00
4f1f003d04 server: add version monitoring 2015-01-22 10:23:15 -08:00
2038 changed files with 75415 additions and 368466 deletions

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.git

6
.gitignore vendored
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/coverage
/gopath
/go-bindata
/machine*
/bin
.vagrant
*.etcd
/etcd
*.swp
/hack/insta-discovery/.env
*.test
tools/functional-tester/docker/bin

1
.godir
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github.com/coreos/etcd

33
.header
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// Copyright 2016 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/*
Copyright 2013 CoreOS Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package x
import (
)

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language: go
sudo: false
go:
- 1.4
- 1.5
- 1.6
- tip
matrix:
allow_failures:
- go: tip
addons:
apt:
packages:
- libpcap-dev
- libaspell-dev
- libhunspell-dev
before_install:
- go get -v github.com/chzchzchz/goword
script:
- ./test

87
CHANGELOG Normal file
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v0.4.6
* Fix long-term timer leak (#900, #875, #868, #904)
* Fix `Running` field in standby_info file (#881)
* Add `quorum=true` query parameter for GET requests (#866, #883)
* Add `Access-Control-Allow-Headers` header for CORS requests (#886)
* Various documentation improvements (#907, #882)
v0.4.5
* Flush headers immediatly on `wait=true` requests (#877)
* Add `ETCD_HTTP_READ_TIMEOUT` and `ETCD_HTTP_WRITE_TIMEOUT` (#880)
* Add `ETCDCTL_PEERS` configuration to etcdctl (#95)
* etcdctl takes stdin for mk (#91)
v0.4.4
* Fix `--no-sync` flag in etcdctl (#83)
* Improved logging for machine removal (#844)
* Various documentation improvements (#858, #851, #847)
v0.4.3
* Avoid panic() on truncated or unexpected log data (#834, #833)
* Fix missing stats field (#807)
* Lengthen default peer removal delay to 30mins (#835)
* Reduce logging on heartbeat timeouts (#836)
v0.4.2
* Improvements to the clustering documents
* Set content-type properly on errors (#469)
* Standbys re-join if they should be part of the cluster (#810, #815, #818)
v0.4.1
* Re-introduce DELETE on the machines endpoint
* Document the machines endpoint
v0.4.0
* Introduced standby mode
* Added HEAD requests
* Set logs NOCOW flag when BTRFS is detected to avoid fsync overhead
* Fix all known data races, and pass Go race detector (TODO: re-run race detector)
* Fixed timeouts when using HTTPS
* Improved snapshot stability
* Migration of machine names to new IPs
* Updated peer discovery ordering
v0.3.0
* Add Compare-and-Delete support.
* Added prevNode to response objects.
* Added Discovery API.
* Add tracing and debug endpoints (Documentation/debugging.md).
* Improved logging of cluster events.
* go get github.com/coreos/etcd works.
* info file is no longer used.
* Snapshots are on by default.
* Statistics APIs documented.
v0.2.0
* Support directory creation and removal.
* Add Compare-and-Swap (CAS) support.
* Support recursive GETs.
* Support fully consistent GETs.
* Allow clients to watch specific paths.
* Allow clients to watch for key expiration.
* Unique key generation.
* Support hidden paths.
* Refactor low-level data store.
* Modularize store, server and API code.
* Integrate Gorilla Web Toolkit.
* Add tiered configuration (command line args, env variables, config file).
* Add peer protocol versioning.
* Add rolling upgrade support for future versions.
* Sync key expiration across cluster.
* Significantly improve test coverage.
* Improve migration testing.
* Configurable snapshot count.
* Reduce TCP connection count.
* Fix TCP connection leak.
* Bug Fixes: https://github.com/coreos/etcd/issues?milestone=1&state=closed
Contributors:
* Xiang Li (@xiangli-cmu)
* Ben Johnson (@benbjohnson)
* Brandon Philips (@philips)
* Yifan (@yifan-gu)
* Rob Szumski
* Hongchao Deng (@fengjingchao)
* Kelsey Hightower (@kelseyhightower)
* Adrián (@adrianlzt)
* Antonio Terreno (@aterreno)

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# How to contribute
etcd is Apache 2.0 licensed and accepts contributions via GitHub pull requests. This document outlines some of the conventions on commit message formatting, contact points for developers and other resources to make getting your contribution into etcd easier.
etcd is Apache 2.0 licensed and accepts contributions via Github pull requests. This document outlines some of the conventions on commit message formatting, contact points for developers and other resources to make getting your contribution into etcd easier.
# Email and chat
@ -12,14 +12,6 @@ etcd is Apache 2.0 licensed and accepts contributions via GitHub pull requests.
- Fork the repository on GitHub
- Read the README.md for build instructions
## Reporting Bugs and Creating Issues
Reporting bugs is one of the best ways to contribute. However, a good bug report
has some very specific qualities, so please read over our short document on
[reporting bugs](https://github.com/coreos/etcd/blob/master/Documentation/reporting_bugs.md)
before you submit your bug report. This document might contain links known
issues, another good reason to take a look there, before reporting your bug.
## Contribution flow
This is a rough outline of what a contributor's workflow looks like:
@ -29,13 +21,12 @@ This is a rough outline of what a contributor's workflow looks like:
- Make sure your commit messages are in the proper format (see below).
- Push your changes to a topic branch in your fork of the repository.
- Submit a pull request to coreos/etcd.
- Your PR must receive a LGTM from two maintainers found in the MAINTAINERS file.
Thanks for your contributions!
### Code style
The coding style suggested by the Golang community is used in etcd. See the [style doc](https://github.com/golang/go/wiki/CodeReviewComments) for details.
The coding style suggested by the Golang community is used in etcd. See [style doc](https://code.google.com/p/go-wiki/wiki/Style) for details.
Please follow this style to make etcd easy to review, maintain and develop.

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FROM golang:onbuild
EXPOSE 4001 7001 2379 2380
FROM ubuntu:12.04
# Let's install go just like Docker (from source).
RUN apt-get update -q
RUN DEBIAN_FRONTEND=noninteractive apt-get install -qy build-essential curl git
RUN curl -s https://storage.googleapis.com/golang/go1.3.src.tar.gz | tar -v -C /usr/local -xz
RUN cd /usr/local/go/src && ./make.bash --no-clean 2>&1
ENV PATH /usr/local/go/bin:$PATH
ADD . /opt/etcd
RUN cd /opt/etcd && ./build
EXPOSE 4001 7001
ENTRYPOINT ["/opt/etcd/bin/etcd"]

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# Snapshot Migration
You can migrate a snapshot of your data from a v0.4.9+ cluster into a new etcd 2.2 cluster using a snapshot migration. After snapshot migration, the etcd indexes of your data will change. Many etcd applications rely on these indexes to behave correctly. This operation should only be done while all etcd applications are stopped.
To get started get the newest data snapshot from the 0.4.9+ cluster:
```
curl http://cluster.example.com:4001/v2/migration/snapshot > backup.snap
```
Now, import the snapshot into your new cluster:
```
etcdctl --endpoint new_cluster.example.com import --snap backup.snap
```
If you have a large amount of data, you can specify more concurrent works to copy data in parallel by using `-c` flag.
If you have hidden keys to copy, you can use `--hidden` flag to specify. For example fleet uses `/_coreos.com/fleet` so to import those keys use `--hidden /_coreos.com`.
And the data will quickly copy into the new cluster:
```
entering dir: /
entering dir: /foo
entering dir: /foo/bar
copying key: /foo/bar/1 1
entering dir: /
entering dir: /foo2
entering dir: /foo2/bar2
copying key: /foo2/bar2/2 2
```

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# Administration
## Data Directory
### Lifecycle
When first started, etcd stores its configuration into a data directory specified by the data-dir configuration parameter.
Configuration is stored in the write ahead log and includes: the local member ID, cluster ID, and initial cluster configuration.
The write ahead log and snapshot files are used during member operation and to recover after a restart.
Having a dedicated disk to store wal files can improve the throughput and stabilize the cluster.
It is highly recommended to dedicate a wal disk and set `--wal-dir` to point to a directory on that device for a production cluster deployment.
If a members data directory is ever lost or corrupted then the user should [remove][remove-a-member] the etcd member from the cluster using `etcdctl` tool.
A user should avoid restarting an etcd member with a data directory from an out-of-date backup.
Using an out-of-date data directory can lead to inconsistency as the member had agreed to store information via raft then re-joins saying it needs that information again.
For maximum safety, if an etcd member suffers any sort of data corruption or loss, it must be removed from the cluster.
Once removed the member can be re-added with an empty data directory.
### Contents
The data directory has two sub-directories in it:
1. wal: write ahead log files are stored here. For details see the [wal package documentation][wal-pkg]
2. snap: log snapshots are stored here. For details see the [snap package documentation][snap-pkg]
If `--wal-dir` flag is set, etcd will write the write ahead log files to the specified directory instead of data directory.
## Cluster Management
### Lifecycle
If you are spinning up multiple clusters for testing it is recommended that you specify a unique initial-cluster-token for the different clusters.
This can protect you from cluster corruption in case of mis-configuration because two members started with different cluster tokens will refuse members from each other.
### Monitoring
It is important to monitor your production etcd cluster for healthy information and runtime metrics.
#### Health Monitoring
At lowest level, etcd exposes health information via HTTP at `/health` in JSON format. If it returns `{"health": "true"}`, then the cluster is healthy. Please note the `/health` endpoint is still an experimental one as in etcd 2.2.
```
$ curl -L http://127.0.0.1:2379/health
{"health": "true"}
```
You can also use etcdctl to check the cluster-wide health information. It will contact all the members of the cluster and collect the health information for you.
```
$./etcdctl cluster-health
member 8211f1d0f64f3269 is healthy: got healthy result from http://127.0.0.1:12379
member 91bc3c398fb3c146 is healthy: got healthy result from http://127.0.0.1:22379
member fd422379fda50e48 is healthy: got healthy result from http://127.0.0.1:32379
cluster is healthy
```
#### Runtime Metrics
etcd uses [Prometheus][prometheus] for metrics reporting in the server. You can read more through the runtime metrics [doc][metrics].
### Debugging
Debugging a distributed system can be difficult. etcd provides several ways to make debug
easier.
#### Enabling Debug Logging
When you want to debug etcd without stopping it, you can enable debug logging at runtime.
etcd exposes logging configuration at `/config/local/log`.
```
$ curl http://127.0.0.1:2379/config/local/log -XPUT -d '{"Level":"DEBUG"}'
$ # debug logging enabled
$
$ curl http://127.0.0.1:2379/config/local/log -XPUT -d '{"Level":"INFO"}'
$ # debug logging disabled
```
#### Debugging Variables
Debug variables are exposed for real-time debugging purposes. Developers who are familiar with etcd can utilize these variables to debug unexpected behavior. etcd exposes debug variables via HTTP at `/debug/vars` in JSON format. The debug variables contains
`cmdline`, `file_descriptor_limit`, `memstats` and `raft.status`.
`cmdline` is the command line arguments passed into etcd.
`file_descriptor_limit` is the max number of file descriptors etcd can utilize.
`memstats` is explained in detail in the [Go runtime documentation][golang-memstats].
`raft.status` is useful when you want to debug low level raft issues if you are familiar with raft internals. In most cases, you do not need to check `raft.status`.
```json
{
"cmdline": ["./etcd"],
"file_descriptor_limit": 0,
"memstats": {"Alloc":4105744,"TotalAlloc":42337320,"Sys":12560632,"...":"..."},
"raft.status": {"id":"ce2a822cea30bfca","term":5,"vote":"ce2a822cea30bfca","commit":23509,"lead":"ce2a822cea30bfca","raftState":"StateLeader","progress":{"ce2a822cea30bfca":{"match":23509,"next":23510,"state":"ProgressStateProbe"}}}
}
```
### Optimal Cluster Size
The recommended etcd cluster size is 3, 5 or 7, which is decided by the fault tolerance requirement. A 7-member cluster can provide enough fault tolerance in most cases. While larger cluster provides better fault tolerance the write performance reduces since data needs to be replicated to more machines.
#### Fault Tolerance Table
It is recommended to have an odd number of members in a cluster. Having an odd cluster size doesn't change the number needed for majority, but you gain a higher tolerance for failure by adding the extra member. You can see this in practice when comparing even and odd sized clusters:
| Cluster Size | Majority | Failure Tolerance |
|--------------|------------|-------------------|
| 1 | 1 | 0 |
| 3 | 2 | 1 |
| 4 | 3 | 1 |
| 5 | 3 | **2** |
| 6 | 4 | 2 |
| 7 | 4 | **3** |
| 8 | 5 | 3 |
| 9 | 5 | **4** |
As you can see, adding another member to bring the size of cluster up to an odd size is always worth it. During a network partition, an odd number of members also guarantees that there will almost always be a majority of the cluster that can continue to operate and be the source of truth when the partition ends.
#### Changing Cluster Size
After your cluster is up and running, adding or removing members is done via [runtime reconfiguration][runtime-reconfig], which allows the cluster to be modified without downtime. The `etcdctl` tool has `member list`, `member add` and `member remove` commands to complete this process.
### Member Migration
When there is a scheduled machine maintenance or retirement, you might want to migrate an etcd member to another machine without losing the data and changing the member ID.
The data directory contains all the data to recover a member to its point-in-time state. To migrate a member:
* Stop the member process.
* Copy the data directory of the now-idle member to the new machine.
* Update the peer URLs for the replaced member to reflect the new machine according to the [runtime reconfiguration instructions][update-member].
* Start etcd on the new machine, using the same configuration and the copy of the data directory.
This example will walk you through the process of migrating the infra1 member to a new machine:
|Name|Peer URL|
|------|--------------|
|infra0|10.0.1.10:2380|
|infra1|10.0.1.11:2380|
|infra2|10.0.1.12:2380|
```sh
$ export ETCDCTL_ENDPOINT=http://10.0.1.10:2379,http://10.0.1.11:2379,http://10.0.1.12:2379
```
```sh
$ etcdctl member list
84194f7c5edd8b37: name=infra0 peerURLs=http://10.0.1.10:2380 clientURLs=http://127.0.0.1:2379,http://10.0.1.10:2379
b4db3bf5e495e255: name=infra1 peerURLs=http://10.0.1.11:2380 clientURLs=http://127.0.0.1:2379,http://10.0.1.11:2379
bc1083c870280d44: name=infra2 peerURLs=http://10.0.1.12:2380 clientURLs=http://127.0.0.1:2379,http://10.0.1.12:2379
```
#### Stop the member etcd process
```sh
$ ssh 10.0.1.11
```
```sh
$ kill `pgrep etcd`
```
#### Copy the data directory of the now-idle member to the new machine
```
$ tar -cvzf infra1.etcd.tar.gz %data_dir%
```
```sh
$ scp infra1.etcd.tar.gz 10.0.1.13:~/
```
#### Update the peer URLs for that member to reflect the new machine
```sh
$ curl http://10.0.1.10:2379/v2/members/b4db3bf5e495e255 -XPUT \
-H "Content-Type: application/json" -d '{"peerURLs":["http://10.0.1.13:2380"]}'
```
Or use `etcdctl member update` command
```sh
$ etcdctl member update b4db3bf5e495e255 http://10.0.1.13:2380
```
#### Start etcd on the new machine, using the same configuration and the copy of the data directory
```sh
$ ssh 10.0.1.13
```
```sh
$ tar -xzvf infra1.etcd.tar.gz -C %data_dir%
```
```
etcd -name infra1 \
-listen-peer-urls http://10.0.1.13:2380 \
-listen-client-urls http://10.0.1.13:2379,http://127.0.0.1:2379 \
-advertise-client-urls http://10.0.1.13:2379,http://127.0.0.1:2379
```
### Disaster Recovery
etcd is designed to be resilient to machine failures. An etcd cluster can automatically recover from any number of temporary failures (for example, machine reboots), and a cluster of N members can tolerate up to _(N-1)/2_ permanent failures (where a member can no longer access the cluster, due to hardware failure or disk corruption). However, in extreme circumstances, a cluster might permanently lose enough members such that quorum is irrevocably lost. For example, if a three-node cluster suffered two simultaneous and unrecoverable machine failures, it would be normally impossible for the cluster to restore quorum and continue functioning.
To recover from such scenarios, etcd provides functionality to backup and restore the datastore and recreate the cluster without data loss.
#### Backing up the datastore
**NB:** Windows users must stop etcd before running the backup command.
The first step of the recovery is to backup the data directory on a functioning etcd node. To do this, use the `etcdctl backup` command, passing in the original data directory used by etcd. For example:
```sh
etcdctl backup \
--data-dir %data_dir% \
--backup-dir %backup_data_dir%
```
This command will rewrite some of the metadata contained in the backup (specifically, the node ID and cluster ID), which means that the node will lose its former identity. In order to recreate a cluster from the backup, you will need to start a new, single-node cluster. The metadata is rewritten to prevent the new node from inadvertently being joined onto an existing cluster.
#### Restoring a backup
To restore a backup using the procedure created above, start etcd with the `-force-new-cluster` option and pointing to the backup directory. This will initialize a new, single-member cluster with the default advertised peer URLs, but preserve the entire contents of the etcd data store. Continuing from the previous example:
```sh
etcd \
-data-dir=%backup_data_dir% \
-force-new-cluster \
...
```
Now etcd should be available on this node and serving the original datastore.
Once you have verified that etcd has started successfully, shut it down and move the data back to the previous location (you may wish to make another copy as well to be safe):
```sh
pkill etcd
rm -fr %data_dir%
mv %backup_data_dir% %data_dir%
etcd \
-data-dir=%data_dir% \
...
```
#### Restoring the cluster
Now that the node is running successfully, [change its advertised peer URLs][update-member], as the `--force-new-cluster` option has set the peer URL to the default listening on localhost.
You can then add more nodes to the cluster and restore resiliency. See the [add a new member][add-a-member] guide for more details. **NB:** If you are trying to restore your cluster using old failed etcd nodes, please make sure you have stopped old etcd instances and removed their old data directories specified by the data-dir configuration parameter.
### Client Request Timeout
etcd sets different timeouts for various types of client requests. The timeout value is not tunable now, which will be improved soon (https://github.com/coreos/etcd/issues/2038).
#### Get requests
Timeout is not set for get requests, because etcd serves the result locally in a non-blocking way.
**Note**: QuorumGet request is a different type, which is mentioned in the following sections.
#### Watch requests
Timeout is not set for watch requests. etcd will not stop a watch request until client cancels it, or the connection is broken.
#### Delete, Put, Post, QuorumGet requests
The default timeout is 5 seconds. It should be large enough to allow all key modifications if the majority of cluster is functioning.
If the request times out, it indicates two possibilities:
1. the server the request sent to was not functioning at that time.
2. the majority of the cluster is not functioning.
If timeout happens several times continuously, administrators should check status of cluster and resolve it as soon as possible.
### Best Practices
#### Maximum OS threads
By default, etcd uses the default configuration of the Go 1.4 runtime, which means that at most one operating system thread will be used to execute code simultaneously. (Note that this default behavior [has changed in Go 1.5][golang1.5-runtime]).
When using etcd in heavy-load scenarios on machines with multiple cores it will usually be desirable to increase the number of threads that etcd can utilize. To do this, simply set the environment variable GOMAXPROCS to the desired number when starting etcd. For more information on this variable, see the [Go runtime documentation][golang-runtime].
[add-a-member]: runtime-configuration.md#add-a-new-member
[golang1.5-runtime]: https://golang.org/doc/go1.5#runtime
[golang-memstats]: https://golang.org/pkg/runtime/#MemStats
[golang-runtime]: https://golang.org/pkg/runtime
[metrics]: metrics.md
[prometheus]: http://prometheus.io/
[remove-a-member]: runtime-configuration.md#remove-a-member
[runtime-reconfig]: runtime-configuration.md#cluster-reconfiguration-operations
[snap-pkg]: http://godoc.org/github.com/coreos/etcd/snap
[update-a-member]: runtime-configuration.md#update-a-member
[wal-pkg]: http://godoc.org/github.com/coreos/etcd/wal

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# etcd3 API
TODO: API doc
## Data Model
etcd is designed to reliably store infrequently updated data and provide reliable watch queries. etcd exposes previous versions of key-value pairs to support inexpensive snapshots and watch history events (“time travel queries”). A persistent, multi-version, concurrency-control data model is a good fit for these use cases.
etcd stores data in a multiversion [persistent][persistent-ds] key-value store. The persistent key-value store preserves the previous version of a key-value pair when its value is superseded with new data. The key-value store is effectively immutable; its operations do not update the structure in-place, but instead always generates a new updated structure. All past versions of keys are still accessible and watchable after modification. To prevent the data store from growing indefinitely over time from maintaining old versions, the store may be compacted to shed the oldest versions of superseded data.
### Logical View
The stores logical view is a flat binary key space. The key space has a lexically sorted index on byte string keys so range queries are inexpensive.
The key space maintains multiple revisions. Each atomic mutative operation (e.g., a transaction operation may contain multiple operations) creates a new revision on the key space. All data held by previous revisions remains unchanged. Old versions of key can still be accessed through previous revisions. Likewise, revisions are indexed as well; ranging over revisions with watchers is efficient. If the store is compacted to recover space, revisions before the compact revision will be removed.
A keys lifetime spans a generation. Each key may have one or multiple generations. Creating a key increments the generation of that key, starting at 1 if the key never existed. Deleting a key generates a key tombstone, concluding the keys current generation. Each modification of a key creates a new version of the key. Once a compaction happens, any generation ended before the given revision will be removed and values set before the compaction revision except the latest one will be removed.
### Physical View
etcd stores the physical data as key-value pairs in a persistent [b+tree][b+tree]. Each revision of the stores state only contains the delta from its previous revision to be efficient. A single revision may correspond to multiple keys in the tree.
The key of key-value pair is a 3-tuple (major, sub, type). Major is the store revision holding the key. Sub differentiates among keys within the same revision. Type is an optional suffix for special value (e.g., `t` if the value contains a tombstone). The value of the key-value pair contains the modification from previous revision, thus one delta from previous revision. The b+tree is ordered by key in lexical byte-order. Ranged lookups over revision deltas are fast; this enables quickly finding modifications from one specific revision to another. Compaction removes out-of-date keys-value pairs.
etcd also keeps a secondary in-memory [btree][btree] index to speed up range queries over keys. The keys in the btree index are the keys of the store exposed to user. The value is a pointer to the modification of the persistent b+tree. Compaction removes dead pointers.
## KV API Guarantees
etcd is a consistent and durable key value store with mini-transaction(TODO: link to txn doc when we have it) support. The key value store is exposed through the KV APIs. etcd tries to ensure the strongest consistency and durability guarantees for a distributed system. This specification enumerates the KV API guarantees made by etcd.
### APIs to consider
* Read APIs
* range
* watch
* Write APIs
* put
* delete
* Combination (read-modify-write) APIs
* txn
### etcd Specific Definitions
#### operation completed
An etcd operation is considered complete when it is committed through consensus, and therefore “executed” -- permanently stored -- by the etcd storage engine. The client knows an operation is completed when it receives a response from the etcd server. Note that the client may be uncertain about the status of an operation if it times out, or there is a network disruption between the client and the etcd member. etcd may also abort operations when there is a leader election. etcd does not send `abort` responses to clients outstanding requests in this event.
#### revision
An etcd operation that modifies the key value store is assigned with a single increasing revision. A transaction operation might modifies the key value store multiple times, but only one revision is assigned. The revision attribute of a key value pair that modified by the operation has the same value as the revision of the operation. The revision can be used as a logical clock for key value store. A key value pair that has a larger revision is modified after a key value pair with a smaller revision. Two key value pairs that have the same revision are modified by an operation "concurrently".
### Guarantees Provided
#### Atomicity
All API requests are atomic; an operation either completes entirely or not at all. For watch requests, all events generated by one operation will be in one watch response. Watch never observes partial events for a single operation.
#### Consistency
All API calls ensure [sequential consistency][seq_consistency], the strongest consistency guarantee available from distributed systems. No matter which etcd member server a client makes requests to, a client reads the same events in the same order. If two members complete the same number of operations, the state of the two members is consistent.
For watch operations, etcd guarantees to return the same value for the same key across all members for the same revision. For range operations, etcd has a similar guarantee for [linearized][Linearizability] access; serialized access may be behind the quorum state, so that the later revision is not yet available.
As with all distributed systems, it is impossible for etcd to ensure [strict consistency][strict_consistency]. etcd does not guarantee that it will return to a read the “most recent” value (as measured by a wall clock when a request is completed) available on any cluster member.
#### Isolation
etcd ensures [serializable isolation][serializable_isolation], which is the highest isolation level available in distributed systems. Read operations will never observe any intermediate data.
#### Durability
Any completed operations are durable. All accessible data is also durable data. A read will never return data that has not been made durable.
#### Linearizability
Linearizability (also known as Atomic Consistency or External Consistency) is a consistency level between strict consistency and sequential consistency.
For linearizability, suppose each operation receives a timestamp from a loosely synchronized global clock. Operations are linearized if and only if they always complete as though they were executed in a sequential order and each operation appears to complete in the order specified by the program. Likewise, if an operations timestamp precedes another, that operation must also precede the other operation in the sequence.
For example, consider a client completing a write at time point 1 (*t1*). A client issuing a read at *t2* (for *t2* > *t1*) should receive a value at least as recent as the previous write, completed at *t1*. However, the read might actually complete only by *t3*, and the returned value, current at *t2* when the read began, might be "stale" by *t3*.
etcd does not ensure linearizability for watch operations. Users are expected to verify the revision of watch responses to ensure correct ordering.
etcd ensures linearizability for all other operations by default. Linearizability comes with a cost, however, because linearized requests must go through the Raft consensus process. To obtain lower latencies and higher throughput for read requests, clients can configure a requests consistency mode to `serializable`, which may access stale data with respect to quorum, but removes the performance penalty of linearized accesses' reliance on live consensus.
[persistent-ds]: [https://en.wikipedia.org/wiki/Persistent_data_structure]
[btree]: [https://en.wikipedia.org/wiki/B-tree]
[b+tree]: [https://en.wikipedia.org/wiki/B%2B_tree]
[seq_consistency]: [https://en.wikipedia.org/wiki/Consistency_model#Sequential_consistency]
[strict_consistency]: [https://en.wikipedia.org/wiki/Consistency_model#Strict_consistency]
[serializable_isolation]: [https://en.wikipedia.org/wiki/Isolation_(database_systems)#Serializable]
[Linearizability]: [#Linearizability]

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# v2 Auth and Security
## etcd Resources
There are three types of resources in etcd
1. permission resources: users and roles in the user store
2. key-value resources: key-value pairs in the key-value store
3. settings resources: security settings, auth settings, and dynamic etcd cluster settings (election/heartbeat)
### Permission Resources
#### Users
A user is an identity to be authenticated. Each user can have multiple roles. The user has a capability (such as reading or writing) on the resource if one of the roles has that capability.
A user named `root` is required before authentication can be enabled, and it always has the ROOT role. The ROOT role can be granted to multiple users, but `root` is required for recovery purposes.
#### Roles
Each role has exact one associated Permission List. An permission list exists for each permission on key-value resources.
The special static ROOT (named `root`) role has a full permissions on all key-value resources, the permission to manage user resources and settings resources. Only the ROOT role has the permission to manage user resources and modify settings resources. The ROOT role is built-in and does not need to be created.
There is also a special GUEST role, named 'guest'. These are the permissions given to unauthenticated requests to etcd. This role will be created automatically, and by default allows access to the full keyspace due to backward compatibility. (etcd did not previously authenticate any actions.). This role can be modified by a ROOT role holder at any time, to reduce the capabilities of unauthenticated users.
#### Permissions
There are two types of permissions, `read` and `write`. All management and settings require the ROOT role.
A Permission List is a list of allowed patterns for that particular permission (read or write). Only ALLOW prefixes are supported. DENY becomes more complicated and is TBD.
### Key-Value Resources
A key-value resource is a key-value pairs in the store. Given a list of matching patterns, permission for any given key in a request is granted if any of the patterns in the list match.
Only prefixes or exact keys are supported. A prefix permission string ends in `*`.
A permission on `/foo` is for that exact key or directory, not its children or recursively. `/foo*` is a prefix that matches `/foo` recursively, and all keys thereunder, and keys with that prefix (eg. `/foobar`. Contrast to the prefix `/foo/*`). `*` alone is permission on the full keyspace.
### Settings Resources
Specific settings for the cluster as a whole. This can include adding and removing cluster members, enabling or disabling authentication, replacing certificates, and any other dynamic configuration by the administrator (holder of the ROOT role).
## v2 Auth
### Basic Auth
We only support [Basic Auth][basic-auth] for the first version. Client needs to attach the basic auth to the HTTP Authorization Header.
### Authorization field for operations
Added to requests to /v2/keys, /v2/auth
Add code 401 Unauthorized to the set of responses from the v2 API
Authorization: Basic {encoded string}
### Future Work
Other types of auth can be considered for the future (eg, signed certs, public keys) but the `Authorization:` header allows for other such types
### Things out of Scope for etcd Permissions
* Pluggable AUTH backends like LDAP (other Authorization tokens generated by LDAP et al may be a possibility)
* Very fine-grained access controls (eg: users modifying keys outside work hours)
## API endpoints
An Error JSON corresponds to:
{
"name": "ErrErrorName",
"description" : "The longer helpful description of the error."
}
#### Enable and Disable Authentication
**Get auth status**
GET /v2/auth/enable
Sent Headers:
Possible Status Codes:
200 OK
200 Body:
{
"enabled": true
}
**Enable auth**
PUT /v2/auth/enable
Sent Headers:
Put Body: (empty)
Possible Status Codes:
200 OK
400 Bad Request (if root user has not been created)
409 Conflict (already enabled)
200 Body: (empty)
**Disable auth**
DELETE /v2/auth/enable
Sent Headers:
Authorization: Basic <RootAuthString>
Possible Status Codes:
200 OK
401 Unauthorized (if not a root user)
409 Conflict (already disabled)
200 Body: (empty)
#### Users
The User JSON object is formed as follows:
```
{
"user": "userName",
"password": "password",
"roles": [
"role1",
"role2"
],
"grant": [],
"revoke": []
}
```
Password is only passed when necessary.
**Get a List of Users**
GET/HEAD /v2/auth/users
Sent Headers:
Authorization: Basic <BasicAuthString>
Possible Status Codes:
200 OK
401 Unauthorized
200 Headers:
Content-type: application/json
200 Body:
{
"users": [
{
"user": "alice",
"roles": [
{
"role": "root",
"permissions": {
"kv": {
"read": ["*"],
"write": ["*"]
}
}
}
]
},
{
"user": "bob",
"roles": [
{
"role": "guest",
"permissions": {
"kv": {
"read": ["*"],
"write": ["*"]
}
}
}
]
}
]
}
**Get User Details**
GET/HEAD /v2/auth/users/alice
Sent Headers:
Authorization: Basic <BasicAuthString>
Possible Status Codes:
200 OK
401 Unauthorized
404 Not Found
200 Headers:
Content-type: application/json
200 Body:
{
"user" : "alice",
"roles" : [
{
"role": "fleet",
"permissions" : {
"kv" : {
"read": [ "/fleet/" ],
"write": [ "/fleet/" ]
}
}
},
{
"role": "etcd",
"permissions" : {
"kv" : {
"read": [ "*" ],
"write": [ "*" ]
}
}
}
]
}
**Create Or Update A User**
A user can be created with initial roles, if filled in. However, no roles are required; only the username and password fields
PUT /v2/auth/users/charlie
Sent Headers:
Authorization: Basic <BasicAuthString>
Put Body:
JSON struct, above, matching the appropriate name
* Starting password and roles when creating.
* Grant/Revoke/Password filled in when updating (to grant roles, revoke roles, or change the password).
Possible Status Codes:
200 OK
201 Created
400 Bad Request
401 Unauthorized
404 Not Found (update non-existent users)
409 Conflict (when granting duplicated roles or revoking non-existent roles)
200 Headers:
Content-type: application/json
200 Body:
JSON state of the user
**Remove A User**
DELETE /v2/auth/users/charlie
Sent Headers:
Authorization: Basic <BasicAuthString>
Possible Status Codes:
200 OK
401 Unauthorized
403 Forbidden (remove root user when auth is enabled)
404 Not Found
200 Headers:
200 Body: (empty)
#### Roles
A full role structure may look like this. A Permission List structure is used for the "permissions", "grant", and "revoke" keys.
```
{
"role" : "fleet",
"permissions" : {
"kv" : {
"read" : [ "/fleet/" ],
"write": [ "/fleet/" ]
}
},
"grant" : {"kv": {...}},
"revoke": {"kv": {...}}
}
```
**Get Role Details**
GET/HEAD /v2/auth/roles/fleet
Sent Headers:
Authorization: Basic <BasicAuthString>
Possible Status Codes:
200 OK
401 Unauthorized
404 Not Found
200 Headers:
Content-type: application/json
200 Body:
{
"role" : "fleet",
"permissions" : {
"kv" : {
"read": [ "/fleet/" ],
"write": [ "/fleet/" ]
}
}
}
**Get a list of Roles**
GET/HEAD /v2/auth/roles
Sent Headers:
Authorization: Basic <BasicAuthString>
Possible Status Codes:
200 OK
401 Unauthorized
200 Headers:
Content-type: application/json
200 Body:
{
"roles": [
{
"role": "fleet",
"permissions": {
"kv": {
"read": ["/fleet/"],
"write": ["/fleet/"]
}
}
},
{
"role": "etcd",
"permissions": {
"kv": {
"read": ["*"],
"write": ["*"]
}
}
},
{
"role": "quay",
"permissions": {
"kv": {
"read": ["*"],
"write": ["*"]
}
}
}
]
}
**Create Or Update A Role**
PUT /v2/auth/roles/rkt
Sent Headers:
Authorization: Basic <BasicAuthString>
Put Body:
Initial desired JSON state, including the role name for verification and:
* Starting permission set if creating
* Granted/Revoked permission set if updating
Possible Status Codes:
200 OK
201 Created
400 Bad Request
401 Unauthorized
404 Not Found (update non-existent roles)
409 Conflict (when granting duplicated permission or revoking non-existent permission)
200 Body:
JSON state of the role
**Remove A Role**
DELETE /v2/auth/roles/rkt
Sent Headers:
Authorization: Basic <BasicAuthString>
Possible Status Codes:
200 OK
401 Unauthorized
403 Forbidden (remove root)
404 Not Found
200 Headers:
200 Body: (empty)
## Example Workflow
Let's walk through an example to show two tenants (applications, in our case) using etcd permissions.
### Create root role
```
PUT /v2/auth/users/root
Put Body:
{"user" : "root", "password": "betterRootPW!"}
```
### Enable auth
```
PUT /v2/auth/enable
```
### Modify guest role (revoke write permission)
```
PUT /v2/auth/roles/guest
Headers:
Authorization: Basic <root:betterRootPW!>
Put Body:
{
"role" : "guest",
"revoke" : {
"kv" : {
"write": [
"*"
]
}
}
}
```
### Create Roles for the Applications
Create the rkt role fully specified:
```
PUT /v2/auth/roles/rkt
Headers:
Authorization: Basic <root:betterRootPW!>
Body:
{
"role" : "rkt",
"permissions" : {
"kv": {
"read": [
"/rkt/*"
],
"write": [
"/rkt/*"
]
}
}
}
```
But let's make fleet just a basic role for now:
```
PUT /v2/auth/roles/fleet
Headers:
Authorization: Basic <root:betterRootPW!>
Body:
{
"role" : "fleet"
}
```
### Optional: Grant some permissions to the roles
Well, we finally figured out where we want fleet to live. Let's fix it.
(Note that we avoided this in the rkt case. So this step is optional.)
```
PUT /v2/auth/roles/fleet
Headers:
Authorization: Basic <root:betterRootPW!>
Put Body:
{
"role" : "fleet",
"grant" : {
"kv" : {
"read": [
"/rkt/fleet",
"/fleet/*"
]
}
}
}
```
### Create Users
Same as before, let's use rocket all at once and fleet separately
```
PUT /v2/auth/users/rktuser
Headers:
Authorization: Basic <root:betterRootPW!>
Body:
{"user" : "rktuser", "password" : "rktpw", "roles" : ["rkt"]}
```
```
PUT /v2/auth/users/fleetuser
Headers:
Authorization: Basic <root:betterRootPW!>
Body:
{"user" : "fleetuser", "password" : "fleetpw"}
```
### Optional: Grant Roles to Users
Likewise, let's explicitly grant fleetuser access.
```
PUT /v2/auth/users/fleetuser
Headers:
Authorization: Basic <root:betterRootPW!>
Body:
{"user": "fleetuser", "grant": ["fleet"]}
```
#### Start to use fleetuser and rktuser
For example:
```
PUT /v2/keys/rkt/RktData
Headers:
Authorization: Basic <rktuser:rktpw>
Body:
value=launch
```
Reads and writes outside the prefixes granted will fail with a 401 Unauthorized.
[basic-auth]: https://en.wikipedia.org/wiki/Basic_access_authentication

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# Authentication Guide
## Overview
Authentication -- having users and roles in etcd -- was added in etcd 2.1. This guide will help you set up basic authentication in etcd.
etcd before 2.1 was a completely open system; anyone with access to the API could change keys. In order to preserve backward compatibility and upgradability, this feature is off by default.
For a full discussion of the RESTful API, see [the authentication API documentation][auth-api]
## Special Users and Roles
There is one special user, `root`, and there are two special roles, `root` and `guest`.
### User `root`
User `root` must be created before security can be activated. It has the `root` role and allows for the changing of anything inside etcd. The idea behind the `root` user is for recovery purposes -- a password is generated and stored somewhere -- and the root role is granted to the administrator accounts on the system. In the future, for troubleshooting and recovery, we will need to assume some access to the system, and future documentation will assume this root user (though anyone with the role will suffice).
### Role `root`
Role `root` cannot be modified, but it may be granted to any user. Having access via the root role not only allows global read-write access (as was the case before 2.1) but allows modification of the authentication policy and all administrative things, like modifying the cluster membership.
### Role `guest`
The `guest` role defines the permissions granted to any request that does not provide an authentication. This will be created on security activation (if it doesn't already exist) to have full access to all keys, as was true in etcd 2.0. It may be modified at any time, and cannot be removed.
## Working with users
The `user` subcommand for `etcdctl` handles all things having to do with user accounts.
A listing of users can be found with
```
$ etcdctl user list
```
Creating a user is as easy as
```
$ etcdctl user add myusername
```
And there will be prompt for a new password.
Roles can be granted and revoked for a user with
```
$ etcdctl user grant myusername -roles foo,bar,baz
$ etcdctl user revoke myusername -roles bar,baz
```
We can look at this user with
```
$ etcdctl user get myusername
```
And the password for a user can be changed with
```
$ etcdctl user passwd myusername
```
Which will prompt again for a new password.
To delete an account, there's always
```
$ etcdctl user remove myusername
```
## Working with roles
The `role` subcommand for `etcdctl` handles all things having to do with access controls for particular roles, as were granted to individual users.
A listing of roles can be found with
```
$ etcdctl role list
```
A new role can be created with
```
$ etcdctl role add myrolename
```
A role has no password; we are merely defining a new set of access rights.
Roles are granted access to various parts of the keyspace, a single path at a time.
Reading a path is simple; if the path ends in `*`, that key **and all keys prefixed with it**, are granted to holders of this role. If it does not end in `*`, only that key and that key alone is granted.
Access can be granted as either read, write, or both, as in the following examples:
```
# Give read access to keys under the /foo directory
$ etcdctl role grant myrolename -path '/foo/*' -read
# Give write-only access to the key at /foo/bar
$ etcdctl role grant myrolename -path '/foo/bar' -write
# Give full access to keys under /pub
$ etcdctl role grant myrolename -path '/pub/*' -readwrite
```
Beware that
```
# Give full access to keys under /pub??
$ etcdctl role grant myrolename -path '/pub*' -readwrite
```
Without the slash may include keys under `/publishing`, for example. To do both, grant `/pub` and `/pub/*`
To see what's granted, we can look at the role at any time:
```
$ etcdctl role get myrolename
```
Revocation of permissions is done the same logical way:
```
$ etcdctl role revoke myrolename -path '/foo/bar' -write
```
As is removing a role entirely
```
$ etcdctl role remove myrolename
```
## Enabling authentication
The minimal steps to enabling auth are as follows. The administrator can set up users and roles before or after enabling authentication, as a matter of preference.
Make sure the root user is created:
```
$ etcdctl user add root
New password:
```
And enable authentication
```
$ etcdctl auth enable
```
After this, etcd is running with authentication enabled. To disable it for any reason, use the reciprocal command:
```
$ etcdctl -u root:rootpw auth disable
```
It would also be good to check what guests (unauthenticated users) are allowed to do:
```
$ etcdctl -u root:rootpw role get guest
```
And modify this role appropriately, depending on your policies.
## Using `etcdctl` to authenticate
`etcdctl` supports a similar flag as `curl` for authentication.
```
$ etcdctl -u user:password get foo
```
or if you prefer to be prompted:
```
$ etcdctl -u user get foo
```
Otherwise, all `etcdctl` commands remain the same. Users and roles can still be created and modified, but require authentication by a user with the root role.
[auth-api]: auth_api.md

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# Backward Compatibility
The main goal of etcd 2.0 release is to improve cluster safety around bootstrapping and dynamic reconfiguration. To do this, we deprecated the old error-prone APIs and provide a new set of APIs.
The other main focus of this release was a more reliable Raft implementation, but as this change is internal it should not have any notable effects to users.
## Command Line Flags Changes
The major flag changes are to mostly related to bootstrapping. The `initial-*` flags provide an improved way to specify the required criteria to start the cluster. The advertised URLs now support a list of values instead of a single value, which allows etcd users to gracefully migrate to the new set of IANA-assigned ports (2379/client and 2380/peers) while maintaining backward compatibility with the old ports.
- `-addr` is replaced by `-advertise-client-urls`.
- `-bind-addr` is replaced by `-listen-client-urls`.
- `-peer-addr` is replaced by `-initial-advertise-peer-urls`.
- `-peer-bind-addr` is replaced by `-listen-peer-urls`.
- `-peers` is replaced by `-initial-cluster`.
- `-peers-file` is replaced by `-initial-cluster`.
- `-peer-heartbeat-interval` is replaced by `-heartbeat-interval`.
- `-peer-election-timeout` is replaced by `-election-timeout`.
The documentation of new command line flags can be found at
https://github.com/coreos/etcd/blob/master/Documentation/configuration.md.
## Data Directory Naming
The default data dir location has changed from {$hostname}.etcd to {name}.etcd.
## Key-Value API
### Read consistency flag
The consistent flag for read operations is removed in etcd 2.0.0. The normal read operations provides the same consistency guarantees with the 0.4.6 read operations with consistent flag set.
The read consistency guarantees are:
The consistent read guarantees the sequential consistency within one client that talks to one etcd server. Read/Write from one client to one etcd member should be observed in order. If one client write a value to an etcd server successfully, it should be able to get the value out of the server immediately.
Each etcd member will proxy the request to leader and only return the result to user after the result is applied on the local member. Thus after the write succeed, the user is guaranteed to see the value on the member it sent the request to.
Reads do not provide linearizability. If you want linearizable read, you need to set quorum option to true.
**Previous behavior**
We added an option for a consistent read in the old version of etcd since etcd 0.x redirects the write request to the leader. When the user get back the result from the leader, the member it sent the request to originally might not apply the write request yet. With the consistent flag set to true, the client will always send read request to the leader. So one client should be able to see its last write when consistent=true is enabled. There is no order guarantees among different clients.
## Standby
etcd 0.4s standby mode has been deprecated. [Proxy mode][proxymode] is introduced to solve a subset of problems standby was solving.
Standby mode was intended for large clusters that had a subset of the members acting in the consensus process. Overall this process was too magical and allowed for operators to back themselves into a corner.
Proxy mode in 2.0 will provide similar functionality, and with improved control over which machines act as proxies due to the operator specifically configuring them. Proxies also support read only or read/write modes for increased security and durability.
[proxymode]: proxy.md
## Discovery Service
A size key needs to be provided inside a [discovery token][discoverytoken].
[discoverytoken]: clustering.md#custom-etcd-discovery-service
## HTTP Admin API
`v2/admin` on peer url and `v2/keys/_etcd` are unified under the new [v2/members API][members-api] to better explain which machines are part of an etcd cluster, and to simplify the keyspace for all your use cases.
[members-api]: members_api.md
## HTTP Key Value API
- The follower can now transparently proxy write requests to the leader. Clients will no longer see 307 redirections to the leader from etcd.
- Expiration time is in UTC instead of local time.

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# Benchmarks
etcd benchmarks will be published regularly and tracked for each release below:
- [etcd v2.1.0-alpha][2.1]
- [etcd v2.2.0-rc][2.2]
- [etcd v3 demo][3.0]
# Memory Usage Benchmarks
It records expected memory usage in different scenarios.
- [etcd v2.2.0-rc][2.2-mem]
[2.1]: etcd-2-1-0-alpha-benchmarks.md
[2.2]: etcd-2-2-0-rc-benchmarks.md
[2.2-mem]: etcd-2-2-0-rc-memory-benchmarks.md
[3.0]: etcd-3-demo-benchmarks.md

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## Physical machines
GCE n1-highcpu-2 machine type
- 1x dedicated local SSD mounted under /var/lib/etcd
- 1x dedicated slow disk for the OS
- 1.8 GB memory
- 2x CPUs
- etcd version 2.1.0 alpha
## etcd Cluster
3 etcd members, each runs on a single machine
## Testing
Bootstrap another machine and use the [boom HTTP benchmark tool][boom] to send requests to each etcd member. Check the [benchmark hacking guide][hack-benchmark] for detailed instructions.
## Performance
### reading one single key
| key size in bytes | number of clients | target etcd server | read QPS | 90th Percentile Latency (ms) |
|-------------------|-------------------|--------------------|----------|---------------|
| 64 | 1 | leader only | 1534 | 0.7 |
| 64 | 64 | leader only | 10125 | 9.1 |
| 64 | 256 | leader only | 13892 | 27.1 |
| 256 | 1 | leader only | 1530 | 0.8 |
| 256 | 64 | leader only | 10106 | 10.1 |
| 256 | 256 | leader only | 14667 | 27.0 |
| 64 | 64 | all servers | 24200 | 3.9 |
| 64 | 256 | all servers | 33300 | 11.8 |
| 256 | 64 | all servers | 24800 | 3.9 |
| 256 | 256 | all servers | 33000 | 11.5 |
### writing one single key
| key size in bytes | number of clients | target etcd server | write QPS | 90th Percentile Latency (ms) |
|-------------------|-------------------|--------------------|-----------|---------------|
| 64 | 1 | leader only | 60 | 21.4 |
| 64 | 64 | leader only | 1742 | 46.8 |
| 64 | 256 | leader only | 3982 | 90.5 |
| 256 | 1 | leader only | 58 | 20.3 |
| 256 | 64 | leader only | 1770 | 47.8 |
| 256 | 256 | leader only | 4157 | 105.3 |
| 64 | 64 | all servers | 1028 | 123.4 |
| 64 | 256 | all servers | 3260 | 123.8 |
| 256 | 64 | all servers | 1033 | 121.5 |
| 256 | 256 | all servers | 3061 | 119.3 |
[boom]: https://github.com/rakyll/boom
[hack-benchmark]: /hack/benchmark/

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# Benchmarking etcd v2.2.0
## Physical Machines
GCE n1-highcpu-2 machine type
- 1x dedicated local SSD mounted as etcd data directory
- 1x dedicated slow disk for the OS
- 1.8 GB memory
- 2x CPUs
## etcd Cluster
3 etcd 2.2.0 members, each runs on a single machine.
Detailed versions:
```
etcd Version: 2.2.0
Git SHA: e4561dd
Go Version: go1.5
Go OS/Arch: linux/amd64
```
## Testing
Bootstrap another machine, outside of the etcd cluster, and run the [`boom` HTTP benchmark tool](https://github.com/rakyll/boom) with a connection reuse patch to send requests to each etcd cluster member. See the [benchmark instructions](../../hack/benchmark/) for the patch and the steps to reproduce our procedures.
The performance is calulated through results of 100 benchmark rounds.
## Performance
### Single Key Read Performance
| key size in bytes | number of clients | target etcd server | average read QPS | read QPS stddev | average 90th Percentile Latency (ms) | latency stddev |
|-------------------|-------------------|--------------------|------------------|-----------------|--------------------------------------|----------------|
| 64 | 1 | leader only | 2303 | 200 | 0.49 | 0.06 |
| 64 | 64 | leader only | 15048 | 685 | 7.60 | 0.46 |
| 64 | 256 | leader only | 14508 | 434 | 29.76 | 1.05 |
| 256 | 1 | leader only | 2162 | 214 | 0.52 | 0.06 |
| 256 | 64 | leader only | 14789 | 792 | 7.69| 0.48 |
| 256 | 256 | leader only | 14424 | 512 | 29.92 | 1.42 |
| 64 | 64 | all servers | 45752 | 2048 | 2.47 | 0.14 |
| 64 | 256 | all servers | 46592 | 1273 | 10.14 | 0.59 |
| 256 | 64 | all servers | 45332 | 1847 | 2.48| 0.12 |
| 256 | 256 | all servers | 46485 | 1340 | 10.18 | 0.74 |
### Single Key Write Performance
| key size in bytes | number of clients | target etcd server | average write QPS | write QPS stddev | average 90th Percentile Latency (ms) | latency stddev |
|-------------------|-------------------|--------------------|------------------|-----------------|--------------------------------------|----------------|
| 64 | 1 | leader only | 55 | 4 | 24.51 | 13.26 |
| 64 | 64 | leader only | 2139 | 125 | 35.23 | 3.40 |
| 64 | 256 | leader only | 4581 | 581 | 70.53 | 10.22 |
| 256 | 1 | leader only | 56 | 4 | 22.37| 4.33 |
| 256 | 64 | leader only | 2052 | 151 | 36.83 | 4.20 |
| 256 | 256 | leader only | 4442 | 560 | 71.59 | 10.03 |
| 64 | 64 | all servers | 1625 | 85 | 58.51 | 5.14 |
| 64 | 256 | all servers | 4461 | 298 | 89.47 | 36.48 |
| 256 | 64 | all servers | 1599 | 94 | 60.11| 6.43 |
| 256 | 256 | all servers | 4315 | 193 | 88.98 | 7.01 |
## Performance Changes
- Because etcd now records metrics for each API call, read QPS performance seems to see a minor decrease in most scenarios. This minimal performance impact was judged a reasonable investment for the breadth of monitoring and debugging information returned.
- Write QPS to cluster leaders seems to be increased by a small margin. This is because the main loop and entry apply loops were decoupled in the etcd raft logic, eliminating several blocks between them.
- Write QPS to all members seems to be increased by a significant margin, because followers now receive the latest commit index sooner, and commit proposals more quickly.

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## Physical machines
GCE n1-highcpu-2 machine type
- 1x dedicated local SSD mounted under /var/lib/etcd
- 1x dedicated slow disk for the OS
- 1.8 GB memory
- 2x CPUs
## etcd Cluster
3 etcd 2.2.0-rc members, each runs on a single machine.
Detailed versions:
```
etcd Version: 2.2.0-alpha.1+git
Git SHA: 59a5a7e
Go Version: go1.4.2
Go OS/Arch: linux/amd64
```
Also, we use 3 etcd 2.1.0 alpha-stage members to form cluster to get base performance. etcd's commit head is at [c7146bd5][c7146bd5], which is the same as the one that we use in [etcd 2.1 benchmark][etcd-2.1-benchmark].
## Testing
Bootstrap another machine and use the [boom HTTP benchmark tool][boom] to send requests to each etcd member. Check the [benchmark hacking guide][hack-benchmark] for detailed instructions.
## Performance
### reading one single key
| key size in bytes | number of clients | target etcd server | read QPS | 90th Percentile Latency (ms) |
|-------------------|-------------------|--------------------|----------|---------------|
| 64 | 1 | leader only | 2804 (-5%) | 0.4 (+0%) |
| 64 | 64 | leader only | 17816 (+0%) | 5.7 (-6%) |
| 64 | 256 | leader only | 18667 (-6%) | 20.4 (+2%) |
| 256 | 1 | leader only | 2181 (-15%) | 0.5 (+25%) |
| 256 | 64 | leader only | 17435 (-7%) | 6.0 (+9%) |
| 256 | 256 | leader only | 18180 (-8%) | 21.3 (+3%) |
| 64 | 64 | all servers | 46965 (-4%) | 2.1 (+0%) |
| 64 | 256 | all servers | 55286 (-6%) | 7.4 (+6%) |
| 256 | 64 | all servers | 46603 (-6%) | 2.1 (+5%) |
| 256 | 256 | all servers | 55291 (-6%) | 7.3 (+4%) |
### writing one single key
| key size in bytes | number of clients | target etcd server | write QPS | 90th Percentile Latency (ms) |
|-------------------|-------------------|--------------------|-----------|---------------|
| 64 | 1 | leader only | 76 (+22%) | 19.4 (-15%) |
| 64 | 64 | leader only | 2461 (+45%) | 31.8 (-32%) |
| 64 | 256 | leader only | 4275 (+1%) | 69.6 (-10%) |
| 256 | 1 | leader only | 64 (+20%) | 16.7 (-30%) |
| 256 | 64 | leader only | 2385 (+30%) | 31.5 (-19%) |
| 256 | 256 | leader only | 4353 (-3%) | 74.0 (+9%) |
| 64 | 64 | all servers | 2005 (+81%) | 49.8 (-55%) |
| 64 | 256 | all servers | 4868 (+35%) | 81.5 (-40%) |
| 256 | 64 | all servers | 1925 (+72%) | 47.7 (-59%) |
| 256 | 256 | all servers | 4975 (+36%) | 70.3 (-36%) |
### performance changes explanation
- read QPS in most scenarios is decreased by 5~8%. The reason is that etcd records store metrics for each store operation. The metrics is important for monitoring and debugging, so this is acceptable.
- write QPS to leader is increased by 20~30%. This is because we decouple raft main loop and entry apply loop, which avoids them blocking each other.
- write QPS to all servers is increased by 30~80% because follower could receive latest commit index earlier and commit proposals faster.
[boom]: https://github.com/rakyll/boom
[c7146bd5]: https://github.com/coreos/etcd/commits/c7146bd5f2c73716091262edc638401bb8229144
[etcd-2.1-benchmark]: etcd-2-1-0-alpha-benchmarks.md
[hack-benchmark]: /hack/benchmark/

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@ -1,47 +0,0 @@
## Physical machine
GCE n1-standard-2 machine type
- 1x dedicated local SSD mounted under /var/lib/etcd
- 1x dedicated slow disk for the OS
- 7.5 GB memory
- 2x CPUs
## etcd
```
etcd Version: 2.2.0-rc.0+git
Git SHA: 103cb5c
Go Version: go1.5
Go OS/Arch: linux/amd64
```
## Testing
Start 3-member etcd cluster, each of which uses 2 cores.
The length of key name is always 64 bytes, which is a reasonable length of average key bytes.
## Memory Maximal Usage
- etcd may use maximal memory if one follower is dead and the leader keeps sending snapshots.
- `max RSS` is the maximal memory usage recorded in 3 runs.
| value bytes | key number | data size(MB) | max RSS(MB) | max RSS/data rate on leader |
|-------------|-------------|---------------|-------------|-----------------------------|
| 128 | 50000 | 6 | 433 | 72x |
| 128 | 100000 | 12 | 659 | 54x |
| 128 | 200000 | 24 | 1466 | 61x |
| 1024 | 50000 | 48 | 1253 | 26x |
| 1024 | 100000 | 96 | 2344 | 24x |
| 1024 | 200000 | 192 | 4361 | 22x |
## Data Size Threshold
- When etcd reaches data size threshold, it may trigger leader election easily and drop part of proposals.
- At most cases, etcd cluster should work smoothly if it doesn't hit the threshold. If it doesn't work well due to insufficient resources, you need to decrease its data size.
| value bytes | key number limitation | suggested data size threshold(MB) | consumed RSS(MB) |
|-------------|-----------------------|-----------------------------------|------------------|
| 128 | 400K | 48 | 2400 |
| 1024 | 300K | 292 | 6500 |

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## Physical machines
GCE n1-highcpu-2 machine type
- 1x dedicated local SSD mounted under /var/lib/etcd
- 1x dedicated slow disk for the OS
- 1.8 GB memory
- 2x CPUs
- etcd version 2.2.0
## etcd Cluster
1 etcd member running in v3 demo mode
## Testing
Use [etcd v3 benchmark tool][etcd-v3-benchmark].
## Performance
### reading one single key
| key size in bytes | number of clients | read QPS | 90th Percentile Latency (ms) |
|-------------------|-------------------|----------|---------------|
| 256 | 1 | 2716 | 0.4 |
| 256 | 64 | 16623 | 6.1 |
| 256 | 256 | 16622 | 21.7 |
The performance is nearly the same as the one with empty server handler.
### reading one single key after putting
| key size in bytes | number of clients | read QPS | 90th Percentile Latency (ms) |
|-------------------|-------------------|----------|---------------|
| 256 | 1 | 2269 | 0.5 |
| 256 | 64 | 13582 | 8.6 |
| 256 | 256 | 13262 | 47.5 |
The performance with empty server handler is not affected by one put. So the
performance downgrade should be caused by storage package.
[etcd-v3-benchmark]: /tools/benchmark/

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@ -1,77 +0,0 @@
# Watch Memory Usage Benchmark
*NOTE*: The watch features are under active development, and their memory usage may change as that development progresses. We do not expect it to significantly increase beyond the figures stated below.
A primary goal of etcd is supporting a very large number of watchers doing a massively large amount of watching. etcd aims to support O(10k) clients, O(100K) watch streams (O(10) streams per client) and O(10M) total watchings (O(100) watching per stream). The memory consumed by each individual watching accounts for the largest portion of etcd's overall usage, and is therefore the focus of current and future optimizations.
Three related components of etcd watch consume physical memory: each `grpc.Conn`, each watch stream, and each instance of the watching activity. `grpc.Conn` maintains the actual TCP connection and other gRPC connection state. Each `grpc.Conn` consumes O(10kb) of memory, and might have multiple watch streams attached.
Each watch stream is an independent HTTP2 connection which consumes another O(10kb) of memory.
Multiple watchings might share one watch stream.
Watching is the actual struct that tracks the changes on the key-value store. Each watching should only consume < O(1kb).
```
+-------+
| watch |
+---------> | foo |
| +-------+
+------+-----+
| stream |
+--------------> | |
| +------+-----+ +-------+
| | | watch |
| +---------> | bar |
+-----+------+ +-------+
| | +------------+
| conn +-------> | stream |
| | | |
+-----+------+ +------------+
|
|
|
| +------------+
+--------------> | stream |
| |
+------------+
```
The theoretical memory consumption of watch can be approximated with the formula:
`memory = c1 * number_of_conn + c2 * avg_number_of_stream_per_conn + c3 * avg_number_of_watch_stream`
## Testing Environment
etcd version
- git head https://github.com/coreos/etcd/commit/185097ffaa627b909007e772c175e8fefac17af3
GCE n1-standard-2 machine type
- 7.5 GB memory
- 2x CPUs
## Overall memory usage
The overall memory usage captures how much [RSS][rss] etcd consumes with the client watchers. While the result may vary by as much as 10%, it is still meaningful, since the goal is to learn about the rough memory usage and the pattern of allocations.
With the benchmark result, we can calculate roughly that `c1 = 17kb`, `c2 = 18kb` and `c3 = 350bytes`. So each additional client connection consumes 17kb of memory and each additional stream consumes 18kb of memory, and each additional watching only cause 350bytes. A single etcd server can maintain millions of watchings with a few GB of memory in normal case.
| clients | streams per client | watchings per stream | total watching | memory usage |
|---------|---------|-----------|----------------|--------------|
| 1k | 1 | 1 | 1k | 50MB |
| 2k | 1 | 1 | 2k | 90MB |
| 5k | 1 | 1 | 5k | 200MB |
| 1k | 10 | 1 | 10k | 217MB |
| 2k | 10 | 1 | 20k | 417MB |
| 5k | 10 | 1 | 50k | 980MB |
| 1k | 50 | 1 | 50k | 1001MB |
| 2k | 50 | 1 | 100k | 1960MB |
| 5k | 50 | 1 | 250k | 4700MB |
| 1k | 50 | 10 | 500k | 1171MB |
| 2k | 50 | 10 | 1M | 2371MB |
| 5k | 50 | 10 | 2.5M | 5710MB |
| 1k | 50 | 100 | 5M | 2380MB |
| 2k | 50 | 100 | 10M | 4672MB |
| 5k | 50 | 100 | 50M | *OOM* |
[rss]: https://en.wikipedia.org/wiki/Resident_set_size

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# Storage Memory Usage Benchmark
<!---todo: link storage to storage design doc-->
Two components of etcd storage consume physical memory. The etcd process allocates an *in-memory index* to speed key lookup. The process's *page cache*, managed by the operating system, stores recently-accessed data from disk for quick re-use.
The in-memory index holds all the keys in a [B-tree][btree] data structure, along with pointers to the on-disk data (the values). Each key in the B-tree may contain multiple pointers, pointing to different versions of its values. The theoretical memory consumption of the in-memory index can hence be approximated with the formula:
`N * (c1 + avg_key_size) + N * (avg_versions_of_key) * (c2 + size_of_pointer)`
where `c1` is the key metadata overhead and `c2` is the version metadata overhead.
The graph shows the detailed structure of the in-memory index B-tree.
```
In mem index
+------------+
| key || ... |
+--------------+ | || |
| | +------------+
| | | v1 || ... |
| disk <----------------| || | Tree Node
| | +------------+
| | | v2 || ... |
| <----------------+ || |
| | +------------+
+--------------+ +-----+ | | |
| | | | |
| +------------+
|
|
^
------+
| ... |
| |
+-----+
| ... | Tree Node
| |
+-----+
| ... |
| |
------+
```
[Page cache memory][pagecache] is managed by the operating system and is not covered in detail in this document.
## Testing Environment
etcd version
- git head https://github.com/coreos/etcd/commit/776e9fb7be7eee5e6b58ab977c8887b4fe4d48db
GCE n1-standard-2 machine type
- 7.5 GB memory
- 2x CPUs
## In-memory index memory usage
In this test, we only benchmark the memory usage of the in-memory index. The goal is to find `c1` and `c2` mentioned above and to understand the hard limit of memory consumption of the storage.
We calculate the memory usage consumption via the Go runtime.ReadMemStats. We calculate the total allocated bytes difference before creating the index and after creating the index. It cannot perfectly reflect the memory usage of the in-memory index itself but can show the rough consumption pattern.
| N | versions | key size | memory usage |
|------|----------|----------|--------------|
| 100K | 1 | 64bytes | 22MB |
| 100K | 5 | 64bytes | 39MB |
| 1M | 1 | 64bytes | 218MB |
| 1M | 5 | 64bytes | 432MB |
| 100K | 1 | 256bytes | 41MB |
| 100K | 5 | 256bytes | 65MB |
| 1M | 1 | 256bytes | 409MB |
| 1M | 5 | 256bytes | 506MB |
Based on the result, we can calculate `c1=120bytes`, `c2=30bytes`. We only need two sets of data to calculate `c1` and `c2`, since they are the only unknown variable in the formula. The `c1=120bytes` and `c2=30bytes` are the average value of the 4 sets of `c1` and `c2` we calculated. The key metadata overhead is still relatively nontrivial (50%) for small key-value pairs. However, this is a significant improvement over the old store, which had at least 1000% overhead.
## Overall memory usage
The overall memory usage captures how much RSS etcd consumes with the storage. The value size should have very little impact on the overall memory usage of etcd, since we keep values on disk and only retain hot values in memory, managed by the OS page cache.
| N | versions | key size | value size | memory usage |
|------|----------|----------|------------|--------------|
| 100K | 1 | 64bytes | 256bytes | 40MB |
| 100K | 5 | 64bytes | 256bytes | 89MB |
| 1M | 1 | 64bytes | 256bytes | 470MB |
| 1M | 5 | 64bytes | 256bytes | 880MB |
| 100K | 1 | 64bytes | 1KB | 102MB |
| 100K | 5 | 64bytes | 1KB | 164MB |
| 1M | 1 | 64bytes | 1KB | 587MB |
| 1M | 5 | 64bytes | 1KB | 836MB |
Based on the result, we know the value size does not significantly impact the memory consumption. There is some minor increase due to more data held in the OS page cache.
[btree]: https://en.wikipedia.org/wiki/B-tree
[pagecache]: https://en.wikipedia.org/wiki/Page_cache

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# Branch Management
## Guide
* New development occurs on the [master branch][master].
* Master branch should always have a green build!
* Backwards-compatible bug fixes should target the master branch and subsequently be ported to stable branches.
* Once the master branch is ready for release, it will be tagged and become the new stable branch.
The etcd team has adopted a *rolling release model* and supports one stable version of etcd.
### Master branch
The `master` branch is our development branch. All new features land here first.
If you want to try new features, pull `master` and play with it. Note that `master` may not be stable because new features may introduce bugs.
Before the release of the next stable version, feature PRs will be frozen. We will focus on the testing, bug-fix and documentation for one to two weeks.
### Stable branches
All branches with prefix `release-` are considered _stable_ branches.
After every minor release (http://semver.org/), we will have a new stable branch for that release. We will keep fixing the backwards-compatible bugs for the latest stable release, but not previous releases. The _patch_ release, incorporating any bug fixes, will be once every two weeks, given any patches.
[master]: https://github.com/coreos/etcd/tree/master

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# Client libraries support matrix for etcd
As etcd features support is really uneven between client libraries, a compatibility matrix can be important.
We will consider in detail only the features of clients supporting the v2 API. Clients still supporting the v1 API *only* are listed below.
## v1-only clients
Clients supporting only the API version 1
- [justinsb/jetcd](https://github.com/justinsb/jetcd) Java
- [transitorykris/etcd-py](https://github.com/transitorykris/etcd-py) Python
- [russellhaering/txetcd](https://github.com/russellhaering/txetcd) Python
- [iconara/etcd-rb](https://github.com/iconara/etcd-rb) Ruby
- [jpfuentes2/etcd-ruby](https://github.com/jpfuentes2/etcd-ruby) Ruby
- [aterreno/etcd-clojure](https://github.com/aterreno/etcd-clojure) Clojure
- [marshall-lee/etcd.erl](https://github.com/marshall-lee/etcd.erl) Erlang
## v2 clients
The v2 API has a lot of features, we will categorize them in a few categories:
- **HTTPS Auth**: Support for SSL-certificate based authentication
- **Reconnect**: If the client is able to reconnect automatically to another server if one fails.
- **Mod/Lock**: Support for the locking module
- **Mod/Leader**: Support for the leader election module
- **GET,PUT,POST,DEL Features**: Support for all the modifiers when calling the etcd server with said HTTP method.
### Supported features matrix
| Client| [go-etcd](https://github.com/coreos/go-etcd) | [jetcd](https://github.com/diwakergupta/jetcd) | [python-etcd](https://github.com/jplana/python-etcd) | [python-etcd-client](https://github.com/dsoprea/PythonEtcdClient) | [node-etcd](https://github.com/stianeikeland/node-etcd) | [nodejs-etcd](https://github.com/lavagetto/nodejs-etcd) | [etcd-ruby](https://github.com/ranjib/etcd-ruby) | [etcd-api](https://github.com/jdarcy/etcd-api) | [cetcd](https://github.com/dwwoelfel/cetcd) | [clj-etcd](https://github.com/rthomas/clj-etcd) | [etcetera](https://github.com/drusellers/etcetera)| [Etcd.jl](https://github.com/forio/Etcd.jl) | [p5-etcd](https://metacpan.org/release/Etcd)
| --- | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
| **HTTPS Auth** | Y | Y | Y | Y | Y | Y | - | - | - | - | - | - | - |
| **Reconnect** | Y | - | Y | Y | - | - | - | Y | - | - | - | - | - |
| **Mod/Lock** | - | - | Y | Y | - | - | - | - | - | - | - | Y | - |
| **Mod/Leader** | - | - | - | Y | - | - | - | - | - | - | - | Y | - |
| **GET Features** | F | B | F | F | F | F | F | B | F | G | F | F | F |
| **PUT Features** | F | B | F | F | F | F | F | G | F | G | F | F | F |
| **POST Features** | F | - | F | F | - | F | F | - | - | - | F | F | F |
| **DEL Features** | F | B | F | F | F | F | F | B | G | B | F | F | F |
**Legend**
**F**: Full support **G**: Good support **B**: Basic support
**Y**: Feature supported **-**: Feature not supported

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# Cluster Discovery
## Overview
Starting an etcd cluster requires that each node knows another in the cluster. If you are trying to bring up a cluster all at once, say using a cloud formation, you also need to coordinate who will be the initial cluster leader. The discovery protocol helps you by providing an automated way to discover other existing peers in a cluster.
For more information on how etcd can locate the cluster, see the [finding the cluster][cluster-finding] documentation.
Please note - at least 3 nodes are required for [cluster availability][optimal-cluster-size].
[cluster-finding]: https://github.com/coreos/etcd/blob/master/Documentation/design/cluster-finding.md
[optimal-cluster-size]: https://github.com/coreos/etcd/blob/master/Documentation/optimal-cluster-size.md
## Using discovery.etcd.io
### Create a Token
To use the discovery API, you must first create a token for your etcd cluster. Visit [https://discovery.etcd.io/new](https://discovery.etcd.io/new) to create a new token.
You can inspect the list of peers by viewing `https://discovery.etcd.io/<token>`.
### Start etcd With the Discovery Flag
Specify the `-discovery` flag when you start each etcd instance. The list of existing peers in the cluster will be downloaded and configured. If the instance is the first peer, it will start as the leader of the cluster.
Here's a full example:
```
TOKEN=$(curl https://discovery.etcd.io/new)
./etcd -name instance1 -peer-addr 10.1.2.3:7001 -addr 10.1.2.3:4001 -discovery $TOKEN
./etcd -name instance2 -peer-addr 10.1.2.4:7001 -addr 10.1.2.4:4001 -discovery $TOKEN
./etcd -name instance3 -peer-addr 10.1.2.5:7001 -addr 10.1.2.5:4001 -discovery $TOKEN
```
## Running Your Own Discovery Endpoint
The discovery API communicates with a separate etcd cluster to store and retrieve the list of peers. CoreOS provides [https://discovery.etcd.io](https://discovery.etcd.io) as a free service, but you can easily run your own etcd cluster for this purpose. Here's an example using an etcd cluster located at `10.10.10.10:4001`:
```
TOKEN="testcluster"
./etcd -name instance1 -peer-addr 10.1.2.3:7001 -addr 10.1.2.3:4001 -discovery http://10.10.10.10:4001/v2/keys/$TOKEN
./etcd -name instance2 -peer-addr 10.1.2.4:7001 -addr 10.1.2.4:4001 -discovery http://10.10.10.10:4001/v2/keys/$TOKEN
./etcd -name instance3 -peer-addr 10.1.2.5:7001 -addr 10.1.2.5:4001 -discovery http://10.10.10.10:4001/v2/keys/$TOKEN
```
If you're interested in how to discovery API works behind the scenes, read about the [Discovery Protocol](https://github.com/coreos/etcd/blob/master/Documentation/discovery-protocol.md).
## Setting Peer Addresses Correctly
The Discovery API submits the `-peer-addr` of each etcd instance to the configured Discovery endpoint. It's important to select an address that *all* peers in the cluster can communicate with. For example, if you're located in two regions of a cloud provider, configuring a private `10.x` address will not work between the two regions, and communication will not be possible between all peers.
## Stale Peers
The discovery API will automatically clean up the address of a stale peer that is no longer part of the cluster. The TTL for this process is a week, which should be long enough to handle any extremely long outage you may encounter. There is no harm in having stale peers in the list until they are cleaned up, since an etcd instance only needs to connect to one valid peer in the cluster to join.
## Lifetime of a Discovery URL
A discovery URL identifies a single etcd cluster. Do not re-use discovery URLs for new clusters.
When a machine starts with a new discovery URL the discovery URL will be activated and record the machine's metadata. If you destroy the whole cluster and attempt to bring the cluster back up with the same discovery URL it will fail. This is intentional because all of the registered machines are gone including their logs so there is nothing to recover the killed cluster.

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# Clustering Guide
## Clustering
## Overview
### Example cluster of three machines
Starting an etcd cluster statically requires that each member knows another in the cluster. In a number of cases, you might not know the IPs of your cluster members ahead of time. In these cases, you can bootstrap an etcd cluster with the help of a discovery service.
Let's explore the use of etcd clustering.
We use Raft as the underlying distributed protocol which provides consistency and persistence of the data across all of the etcd instances.
Once an etcd cluster is up and running, adding or removing members is done via [runtime reconfiguration][runtime-conf]. To better understand the design behind runtime reconfiguration, we suggest you read [the runtime configuration design document][runtime-reconf-design].
Let start by creating 3 new etcd instances.
This guide will cover the following mechanisms for bootstrapping an etcd cluster:
We use `-peer-addr` to specify server port and `-addr` to specify client port and `-data-dir` to specify the directory to store the log and info of the machine in the cluster:
* [Static](#static)
* [etcd Discovery](#etcd-discovery)
* [DNS Discovery](#dns-discovery)
```sh
./etcd -peer-addr 127.0.0.1:7001 -addr 127.0.0.1:4001 -data-dir machines/machine1 -name machine1
```
Each of the bootstrapping mechanisms will be used to create a three machine etcd cluster with the following details:
**Note:** If you want to run etcd on an external IP address and still have access locally, you'll need to add `-bind-addr 0.0.0.0` so that it will listen on both external and localhost addresses.
A similar argument `-peer-bind-addr` is used to setup the listening address for the server port.
|Name|Address|Hostname|
|------|---------|------------------|
|infra0|10.0.1.10|infra0.example.com|
|infra1|10.0.1.11|infra1.example.com|
|infra2|10.0.1.12|infra2.example.com|
Let's join two more machines to this cluster using the `-peers` argument. A single connection to any peer will allow a new machine to join, but multiple can be specified for greater resiliency.
## Static
```sh
./etcd -peer-addr 127.0.0.1:7002 -addr 127.0.0.1:4002 -peers 127.0.0.1:7001,127.0.0.1:7003 -data-dir machines/machine2 -name machine2
./etcd -peer-addr 127.0.0.1:7003 -addr 127.0.0.1:4003 -peers 127.0.0.1:7001,127.0.0.1:7002 -data-dir machines/machine3 -name machine3
```
As we know the cluster members, their addresses and the size of the cluster before starting, we can use an offline bootstrap configuration by setting the `initial-cluster` flag. Each machine will get either the following command line or environment variables:
We can retrieve a list of machines in the cluster using the HTTP API:
```sh
curl -L http://127.0.0.1:4001/v2/machines
```
We should see there are three machines in the cluster
```
ETCD_INITIAL_CLUSTER="infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380"
ETCD_INITIAL_CLUSTER_STATE=new
http://127.0.0.1:4001, http://127.0.0.1:4002, http://127.0.0.1:4003
```
The machine list is also available via the main key API:
```sh
curl -L http://127.0.0.1:4001/v2/keys/_etcd/machines
```
```json
{
"action": "get",
"node": {
"createdIndex": 1,
"dir": true,
"key": "/_etcd/machines",
"modifiedIndex": 1,
"nodes": [
{
"createdIndex": 1,
"key": "/_etcd/machines/machine1",
"modifiedIndex": 1,
"value": "raft=http://127.0.0.1:7001&etcd=http://127.0.0.1:4001"
},
{
"createdIndex": 2,
"key": "/_etcd/machines/machine2",
"modifiedIndex": 2,
"value": "raft=http://127.0.0.1:7002&etcd=http://127.0.0.1:4002"
},
{
"createdIndex": 3,
"key": "/_etcd/machines/machine3",
"modifiedIndex": 3,
"value": "raft=http://127.0.0.1:7003&etcd=http://127.0.0.1:4003"
}
]
}
}
```
We can also get the current leader in the cluster:
```
curl -L http://127.0.0.1:4001/v2/leader
```
The first server we set up should still be the leader unless it has died during these commands.
```
http://127.0.0.1:7001
```
Now we can do normal SET and GET operations on keys as we explored earlier.
```sh
curl -L http://127.0.0.1:4001/v2/keys/foo -XPUT -d value=bar
```
```json
{
"action": "set",
"node": {
"createdIndex": 4,
"key": "/foo",
"modifiedIndex": 4,
"value": "bar"
}
}
```
### Rejoining to the Cluster
If one machine disconnects from the cluster, it could rejoin the cluster automatically when the communication is recovered.
If one machine is killed, it could rejoin the cluster when started with old name. If the peer address is changed, etcd will treat the new peer address as the refreshed one, which benefits instance migration, or virtual machine boot with different IP. The peer-address-changing functionality is only supported when the majority of the cluster is alive, because this behavior needs the consensus of the etcd cluster.
**Note:** For now, it is user responsibility to ensure that the machine doesn't join the cluster that has the member with the same name. Or unexpected error will happen. It would be improved sooner or later.
### Killing Nodes in the Cluster
Now if we kill the leader of the cluster, we can get the value from one of the other two machines:
```sh
curl -L http://127.0.0.1:4002/v2/keys/foo
```
We can also see that a new leader has been elected:
```
curl -L http://127.0.0.1:4002/v2/leader
```
```
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380 \
--initial-cluster-state new
http://127.0.0.1:7002
```
Note that the URLs specified in `initial-cluster` are the _advertised peer URLs_, i.e. they should match the value of `initial-advertise-peer-urls` on the respective nodes.
If you are spinning up multiple clusters (or creating and destroying a single cluster) with same configuration for testing purpose, it is highly recommended that you specify a unique `initial-cluster-token` for the different clusters. By doing this, etcd can generate unique cluster IDs and member IDs for the clusters even if they otherwise have the exact same configuration. This can protect you from cross-cluster-interaction, which might corrupt your clusters.
etcd listens on [`listen-client-urls`][conf-listen-client] to accept client traffic. etcd member advertises the URLs specified in [`advertise-client-urls`][conf-adv-client] to other members, proxies, clients. Please make sure the `advertise-client-urls` are reachable from intended clients. A common mistake is setting `advertise-client-urls` to localhost or leave it as default when you want the remote clients to reach etcd.
On each machine you would start etcd with these flags:
or
```
$ etcd --name infra0 --initial-advertise-peer-urls http://10.0.1.10:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380 \
--initial-cluster-state new
```
```
$ etcd --name infra1 --initial-advertise-peer-urls http://10.0.1.11:2380 \
--listen-peer-urls http://10.0.1.11:2380 \
--listen-client-urls http://10.0.1.11:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.11:2379 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380 \
--initial-cluster-state new
```
```
$ etcd --name infra2 --initial-advertise-peer-urls http://10.0.1.12:2380 \
--listen-peer-urls http://10.0.1.12:2380 \
--listen-client-urls http://10.0.1.12:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.12:2379 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380 \
--initial-cluster-state new
http://127.0.0.1:7003
```
The command line parameters starting with `--initial-cluster` will be ignored on subsequent runs of etcd. You are free to remove the environment variables or command line flags after the initial bootstrap process. If you need to make changes to the configuration later (for example, adding or removing members to/from the cluster), see the [runtime configuration][runtime-conf] guide.
### Error Cases
### Testing Persistence
In the following example, we have not included our new host in the list of enumerated nodes. If this is a new cluster, the node _must_ be added to the list of initial cluster members.
Next we'll kill all the machines to test persistence.
Type `CTRL-C` on each terminal and then rerun the same command you used to start each machine.
```
$ etcd --name infra1 --initial-advertise-peer-urls http://10.0.1.11:2380 \
--listen-peer-urls https://10.0.1.11:2380 \
--listen-client-urls http://10.0.1.11:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.11:2379 \
--initial-cluster infra0=http://10.0.1.10:2380 \
--initial-cluster-state new
etcd: infra1 not listed in the initial cluster config
exit 1
Your request for the `foo` key will return the correct value:
```sh
curl -L http://127.0.0.1:4002/v2/keys/foo
```
In this example, we are attempting to map a node (infra0) on a different address (127.0.0.1:2380) than its enumerated address in the cluster list (10.0.1.10:2380). If this node is to listen on multiple addresses, all addresses _must_ be reflected in the "initial-cluster" configuration directive.
```
$ etcd --name infra0 --initial-advertise-peer-urls http://127.0.0.1:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380 \
--initial-cluster-state=new
etcd: error setting up initial cluster: infra0 has different advertised URLs in the cluster and advertised peer URLs list
exit 1
```json
{
"action": "get",
"node": {
"createdIndex": 4,
"key": "/foo",
"modifiedIndex": 4,
"value": "bar"
}
}
```
If you configure a peer with a different set of configuration and attempt to join this cluster you will get a cluster ID mismatch and etcd will exit.
```
$ etcd --name infra3 --initial-advertise-peer-urls http://10.0.1.13:2380 \
--listen-peer-urls http://10.0.1.13:2380 \
--listen-client-urls http://10.0.1.13:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.13:2379 \
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra3=http://10.0.1.13:2380 \
--initial-cluster-state=new
etcd: conflicting cluster ID to the target cluster (c6ab534d07e8fcc4 != bc25ea2a74fb18b0). Exiting.
exit 1
```
### Using HTTPS between servers
## Discovery
In the previous example we showed how to use SSL client certs for client-to-server communication.
Etcd can also do internal server-to-server communication using SSL client certs.
To do this just change the `-*-file` flags to `-peer-*-file`.
In a number of cases, you might not know the IPs of your cluster peers ahead of time. This is common when utilizing cloud providers or when your network uses DHCP. In these cases, rather than specifying a static configuration, you can use an existing etcd cluster to bootstrap a new one. We call this process "discovery".
There two methods that can be used for discovery:
* etcd discovery service
* DNS SRV records
### etcd Discovery
To better understand the design about discovery service protocol, we suggest you read [this][discovery-proto].
#### Lifetime of a Discovery URL
A discovery URL identifies a unique etcd cluster. Instead of reusing a discovery URL, you should always create discovery URLs for new clusters.
Moreover, discovery URLs should ONLY be used for the initial bootstrapping of a cluster. To change cluster membership after the cluster is already running, see the [runtime reconfiguration][runtime-conf] guide.
#### Custom etcd Discovery Service
Discovery uses an existing cluster to bootstrap itself. If you are using your own etcd cluster you can create a URL like so:
```
$ curl -X PUT https://myetcd.local/v2/keys/discovery/6c007a14875d53d9bf0ef5a6fc0257c817f0fb83/_config/size -d value=3
```
By setting the size key to the URL, you create a discovery URL with an expected cluster size of 3.
If you bootstrap an etcd cluster using discovery service with more than the expected number of etcd members, the extra etcd processes will [fall back][fall-back] to being [proxies][proxy] by default.
The URL you will use in this case will be `https://myetcd.local/v2/keys/discovery/6c007a14875d53d9bf0ef5a6fc0257c817f0fb83` and the etcd members will use the `https://myetcd.local/v2/keys/discovery/6c007a14875d53d9bf0ef5a6fc0257c817f0fb83` directory for registration as they start.
**Each member must have a different name flag specified. `Hostname` or `machine-id` can be a good choice. Or discovery will fail due to duplicated name.**
Now we start etcd with those relevant flags for each member:
```
$ etcd --name infra0 --initial-advertise-peer-urls http://10.0.1.10:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--discovery https://myetcd.local/v2/keys/discovery/6c007a14875d53d9bf0ef5a6fc0257c817f0fb83
```
```
$ etcd --name infra1 --initial-advertise-peer-urls http://10.0.1.11:2380 \
--listen-peer-urls http://10.0.1.11:2380 \
--listen-client-urls http://10.0.1.11:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.11:2379 \
--discovery https://myetcd.local/v2/keys/discovery/6c007a14875d53d9bf0ef5a6fc0257c817f0fb83
```
```
$ etcd --name infra2 --initial-advertise-peer-urls http://10.0.1.12:2380 \
--listen-peer-urls http://10.0.1.12:2380 \
--listen-client-urls http://10.0.1.12:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.12:2379 \
--discovery https://myetcd.local/v2/keys/discovery/6c007a14875d53d9bf0ef5a6fc0257c817f0fb83
```
This will cause each member to register itself with the custom etcd discovery service and begin the cluster once all machines have been registered.
#### Public etcd Discovery Service
If you do not have access to an existing cluster, you can use the public discovery service hosted at `discovery.etcd.io`. You can create a private discovery URL using the "new" endpoint like so:
```
$ curl https://discovery.etcd.io/new?size=3
https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
```
This will create the cluster with an initial expected size of 3 members. If you do not specify a size, a default of 3 will be used.
If you bootstrap an etcd cluster using discovery service with more than the expected number of etcd members, the extra etcd processes will [fall back][fall-back] to being [proxies][proxy] by default.
```
ETCD_DISCOVERY=https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
```
```
-discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
```
**Each member must have a different name flag specified. `Hostname` or `machine-id` can be a good choice. Or discovery will fail due to duplicated name.**
Now we start etcd with those relevant flags for each member:
```
$ etcd --name infra0 --initial-advertise-peer-urls http://10.0.1.10:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
```
```
$ etcd --name infra1 --initial-advertise-peer-urls http://10.0.1.11:2380 \
--listen-peer-urls http://10.0.1.11:2380 \
--listen-client-urls http://10.0.1.11:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.11:2379 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
```
```
$ etcd --name infra2 --initial-advertise-peer-urls http://10.0.1.12:2380 \
--listen-peer-urls http://10.0.1.12:2380 \
--listen-client-urls http://10.0.1.12:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.12:2379 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
```
This will cause each member to register itself with the discovery service and begin the cluster once all members have been registered.
You can use the environment variable `ETCD_DISCOVERY_PROXY` to cause etcd to use an HTTP proxy to connect to the discovery service.
#### Error and Warning Cases
##### Discovery Server Errors
```
$ etcd --name infra0 --initial-advertise-peer-urls http://10.0.1.10:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
etcd: error: the cluster doesnt have a size configuration value in https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de/_config
exit 1
```
##### User Errors
This error will occur if the discovery cluster already has the configured number of members, and `discovery-fallback` is explicitly disabled
```
$ etcd --name infra0 --initial-advertise-peer-urls http://10.0.1.10:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de \
--discovery-fallback exit
etcd: discovery: cluster is full
exit 1
```
##### Warnings
This is a harmless warning notifying you that the discovery URL will be
ignored on this machine.
```
$ etcd --name infra0 --initial-advertise-peer-urls http://10.0.1.10:2380 \
--listen-peer-urls http://10.0.1.10:2380 \
--listen-client-urls http://10.0.1.10:2379,http://127.0.0.1:2379 \
--advertise-client-urls http://10.0.1.10:2379 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de
etcdserver: discovery token ignored since a cluster has already been initialized. Valid log found at /var/lib/etcd
```
### DNS Discovery
DNS [SRV records][rfc-srv] can be used as a discovery mechanism.
The `-discovery-srv` flag can be used to set the DNS domain name where the discovery SRV records can be found.
The following DNS SRV records are looked up in the listed order:
* _etcd-server-ssl._tcp.example.com
* _etcd-server._tcp.example.com
If `_etcd-server-ssl._tcp.example.com` is found then etcd will attempt the bootstrapping process over SSL.
To help clients discover the etcd cluster, the following DNS SRV records are looked up in the listed order:
* _etcd-client._tcp.example.com
* _etcd-client-ssl._tcp.example.com
If `_etcd-client-ssl._tcp.example.com` is found, clients will attempt to communicate with the etcd cluster over SSL.
#### Create DNS SRV records
```
$ dig +noall +answer SRV _etcd-server._tcp.example.com
_etcd-server._tcp.example.com. 300 IN SRV 0 0 2380 infra0.example.com.
_etcd-server._tcp.example.com. 300 IN SRV 0 0 2380 infra1.example.com.
_etcd-server._tcp.example.com. 300 IN SRV 0 0 2380 infra2.example.com.
```
```
$ dig +noall +answer SRV _etcd-client._tcp.example.com
_etcd-client._tcp.example.com. 300 IN SRV 0 0 2379 infra0.example.com.
_etcd-client._tcp.example.com. 300 IN SRV 0 0 2379 infra1.example.com.
_etcd-client._tcp.example.com. 300 IN SRV 0 0 2379 infra2.example.com.
```
```
$ dig +noall +answer infra0.example.com infra1.example.com infra2.example.com
infra0.example.com. 300 IN A 10.0.1.10
infra1.example.com. 300 IN A 10.0.1.11
infra2.example.com. 300 IN A 10.0.1.12
```
#### Bootstrap the etcd cluster using DNS
etcd cluster members can listen on domain names or IP address, the bootstrap process will resolve DNS A records.
The resolved address in `--initial-advertise-peer-urls` *must match* one of the resolved addresses in the SRV targets. The etcd member reads the resolved address to find out if it belongs to the cluster defined in the SRV records.
```
$ etcd --name infra0 \
--discovery-srv example.com \
--initial-advertise-peer-urls http://infra0.example.com:2380 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster-state new \
--advertise-client-urls http://infra0.example.com:2379 \
--listen-client-urls http://infra0.example.com:2379 \
--listen-peer-urls http://infra0.example.com:2380
```
```
$ etcd --name infra1 \
--discovery-srv example.com \
--initial-advertise-peer-urls http://infra1.example.com:2380 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster-state new \
--advertise-client-urls http://infra1.example.com:2379 \
--listen-client-urls http://infra1.example.com:2379 \
--listen-peer-urls http://infra1.example.com:2380
```
```
$ etcd --name infra2 \
--discovery-srv example.com \
--initial-advertise-peer-urls http://infra2.example.com:2380 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster-state new \
--advertise-client-urls http://infra2.example.com:2379 \
--listen-client-urls http://infra2.example.com:2379 \
--listen-peer-urls http://infra2.example.com:2380
```
You can also bootstrap the cluster using IP addresses instead of domain names:
```
$ etcd --name infra0 \
--discovery-srv example.com \
--initial-advertise-peer-urls http://10.0.1.10:2380 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster-state new \
--advertise-client-urls http://10.0.1.10:2379 \
--listen-client-urls http://10.0.1.10:2379 \
--listen-peer-urls http://10.0.1.10:2380
```
```
$ etcd --name infra1 \
--discovery-srv example.com \
--initial-advertise-peer-urls http://10.0.1.11:2380 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster-state new \
--advertise-client-urls http://10.0.1.11:2379 \
--listen-client-urls http://10.0.1.11:2379 \
--listen-peer-urls http://10.0.1.11:2380
```
```
$ etcd --name infra2 \
--discovery-srv example.com \
--initial-advertise-peer-urls http://10.0.1.12:2380 \
--initial-cluster-token etcd-cluster-1 \
--initial-cluster-state new \
--advertise-client-urls http://10.0.1.12:2379 \
--listen-client-urls http://10.0.1.12:2379 \
--listen-peer-urls http://10.0.1.12:2380
```
#### etcd proxy configuration
DNS SRV records can also be used to configure the list of peers for an etcd server running in proxy mode:
```
$ etcd --proxy on --discovery-srv example.com
```
#### etcd client configuration
DNS SRV records can also be used to help clients discover the etcd cluster.
The official [etcd/client][client] supports [DNS Discovery][client-discoverer].
`etcdctl` also supports DNS Discovery by specifying the `--discovery-srv` option.
```
$ etcdctl --discovery-srv example.com set foo bar
```
#### Error Cases
You might see an error like `cannot find local etcd $name from SRV records.`. That means the etcd member fails to find itself from the cluster defined in SRV records. The resolved address in `--initial-advertise-peer-urls` *must match* one of the resolved addresses in the SRV targets.
# 0.4 to 2.0+ Migration Guide
In etcd 2.0 we introduced the ability to listen on more than one address and to advertise multiple addresses. This makes using etcd easier when you have complex networking, such as private and public networks on various cloud providers.
To make understanding this feature easier, we changed the naming of some flags, but we support the old flags to make the migration from the old to new version easier.
|Old Flag |New Flag |Migration Behavior |
|-----------------------|-----------------------|---------------------------------------------------------------------------------------|
|-peer-addr |--initial-advertise-peer-urls |If specified, peer-addr will be used as the only peer URL. Error if both flags specified.|
|-addr |--advertise-client-urls |If specified, addr will be used as the only client URL. Error if both flags specified.|
|-peer-bind-addr |--listen-peer-urls |If specified, peer-bind-addr will be used as the only peer bind URL. Error if both flags specified.|
|-bind-addr |--listen-client-urls |If specified, bind-addr will be used as the only client bind URL. Error if both flags specified.|
|-peers |none |Deprecated. The --initial-cluster flag provides a similar concept with different semantics. Please read this guide on cluster startup.|
|-peers-file |none |Deprecated. The --initial-cluster flag provides a similar concept with different semantics. Please read this guide on cluster startup.|
[client]: /client
[client-discoverer]: https://godoc.org/github.com/coreos/etcd/client#Discoverer
[conf-adv-client]: configuration.md#-advertise-client-urls
[conf-listen-client]: configuration.md#-listen-client-urls
[discovery-proto]: discovery_protocol.md
[fall-back]: proxy.md#fallback-to-proxy-mode-with-discovery-service
[proxy]: proxy.md
[rfc-srv]: http://www.ietf.org/rfc/rfc2052.txt
[runtime-conf]: runtime-configuration.md
[runtime-reconf-design]: runtime-reconf-design.md
If you are using SSL for server-to-server communication, you must use it on all instances of etcd.

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# Configuration Flags
etcd is configurable through command-line flags and environment variables. Options set on the command line take precedence over those from the environment.
The format of environment variable for flag `--my-flag` is `ETCD_MY_FLAG`. It applies to all flags.
The [official etcd ports][iana-ports] are 2379 for client requests, and 2380 for peer communication. Some legacy code and documentation still references ports 4001 and 7001, but all new etcd use and discussion should adopt the assigned ports.
To start etcd automatically using custom settings at startup in Linux, using a [systemd][systemd-intro] unit is highly recommended.
[systemd-intro]: http://freedesktop.org/wiki/Software/systemd/
## Member Flags
### --name
+ Human-readable name for this member.
+ default: "default"
+ env variable: ETCD_NAME
+ This value is referenced as this node's own entries listed in the `--initial-cluster` flag (Ex: `default=http://localhost:2380` or `default=http://localhost:2380,default=http://localhost:7001`). This needs to match the key used in the flag if you're using [static bootstrapping][build-cluster]. When using discovery, each member must have a unique name. `Hostname` or `machine-id` can be a good choice.
### --data-dir
+ Path to the data directory.
+ default: "${name}.etcd"
+ env variable: ETCD_DATA_DIR
### --wal-dir
+ Path to the dedicated wal directory. If this flag is set, etcd will write the WAL files to the walDir rather than the dataDir. This allows a dedicated disk to be used, and helps avoid io competition between logging and other IO operations.
+ default: ""
+ env variable: ETCD_WAL_DIR
### --snapshot-count
+ Number of committed transactions to trigger a snapshot to disk.
+ default: "10000"
+ env variable: ETCD_SNAPSHOT_COUNT
### --heartbeat-interval
+ Time (in milliseconds) of a heartbeat interval.
+ default: "100"
+ env variable: ETCD_HEARTBEAT_INTERVAL
### --election-timeout
+ Time (in milliseconds) for an election to timeout. See [Documentation/tuning.md](tuning.md#time-parameters) for details.
+ default: "1000"
+ env variable: ETCD_ELECTION_TIMEOUT
### --listen-peer-urls
+ List of URLs to listen on for peer traffic. This flag tells the etcd to accept incoming requests from its peers on the specified scheme://IP:port combinations. Scheme can be either http or https.If 0.0.0.0 is specified as the IP, etcd listens to the given port on all interfaces. If an IP address is given as well as a port, etcd will listen on the given port and interface. Multiple URLs may be used to specify a number of addresses and ports to listen on. The etcd will respond to requests from any of the listed addresses and ports.
+ default: "http://localhost:2380,http://localhost:7001"
+ env variable: ETCD_LISTEN_PEER_URLS
+ example: "http://10.0.0.1:2380"
+ invalid example: "http://example.com:2380" (domain name is invalid for binding)
### --listen-client-urls
+ List of URLs to listen on for client traffic. This flag tells the etcd to accept incoming requests from the clients on the specified scheme://IP:port combinations. Scheme can be either http or https. If 0.0.0.0 is specified as the IP, etcd listens to the given port on all interfaces. If an IP address is given as well as a port, etcd will listen on the given port and interface. Multiple URLs may be used to specify a number of addresses and ports to listen on. The etcd will respond to requests from any of the listed addresses and ports.
+ default: "http://localhost:2379,http://localhost:4001"
+ env variable: ETCD_LISTEN_CLIENT_URLS
+ example: "http://10.0.0.1:2379"
+ invalid example: "http://example.com:2379" (domain name is invalid for binding)
### --max-snapshots
+ Maximum number of snapshot files to retain (0 is unlimited)
+ default: 5
+ env variable: ETCD_MAX_SNAPSHOTS
+ The default for users on Windows is unlimited, and manual purging down to 5 (or your preference for safety) is recommended.
### --max-wals
+ Maximum number of wal files to retain (0 is unlimited)
+ default: 5
+ env variable: ETCD_MAX_WALS
+ The default for users on Windows is unlimited, and manual purging down to 5 (or your preference for safety) is recommended.
### --cors
+ Comma-separated white list of origins for CORS (cross-origin resource sharing).
+ default: none
+ env variable: ETCD_CORS
## Clustering Flags
`--initial` prefix flags are used in bootstrapping ([static bootstrap][build-cluster], [discovery-service bootstrap][discovery] or [runtime reconfiguration][reconfig]) a new member, and ignored when restarting an existing member.
`--discovery` prefix flags need to be set when using [discovery service][discovery].
### --initial-advertise-peer-urls
+ List of this member's peer URLs to advertise to the rest of the cluster. These addresses are used for communicating etcd data around the cluster. At least one must be routable to all cluster members. These URLs can contain domain names.
+ default: "http://localhost:2380,http://localhost:7001"
+ env variable: ETCD_INITIAL_ADVERTISE_PEER_URLS
+ example: "http://example.com:2380, http://10.0.0.1:2380"
### --initial-cluster
+ Initial cluster configuration for bootstrapping.
+ default: "default=http://localhost:2380,default=http://localhost:7001"
+ env variable: ETCD_INITIAL_CLUSTER
+ The key is the value of the `--name` flag for each node provided. The default uses `default` for the key because this is the default for the `--name` flag.
### --initial-cluster-state
+ Initial cluster state ("new" or "existing"). Set to `new` for all members present during initial static or DNS bootstrapping. If this option is set to `existing`, etcd will attempt to join the existing cluster. If the wrong value is set, etcd will attempt to start but fail safely.
+ default: "new"
+ env variable: ETCD_INITIAL_CLUSTER_STATE
[static bootstrap]: clustering.md#static
### --initial-cluster-token
+ Initial cluster token for the etcd cluster during bootstrap.
+ default: "etcd-cluster"
+ env variable: ETCD_INITIAL_CLUSTER_TOKEN
### --advertise-client-urls
+ List of this member's client URLs to advertise to the rest of the cluster. These URLs can contain domain names.
+ default: "http://localhost:2379,http://localhost:4001"
+ env variable: ETCD_ADVERTISE_CLIENT_URLS
+ example: "http://example.com:2379, http://10.0.0.1:2379"
+ Be careful if you are advertising URLs such as http://localhost:2379 from a cluster member and are using the proxy feature of etcd. This will cause loops, because the proxy will be forwarding requests to itself until its resources (memory, file descriptors) are eventually depleted.
### --discovery
+ Discovery URL used to bootstrap the cluster.
+ default: none
+ env variable: ETCD_DISCOVERY
### --discovery-srv
+ DNS srv domain used to bootstrap the cluster.
+ default: none
+ env variable: ETCD_DISCOVERY_SRV
### --discovery-fallback
+ Expected behavior ("exit" or "proxy") when discovery services fails.
+ default: "proxy"
+ env variable: ETCD_DISCOVERY_FALLBACK
### --discovery-proxy
+ HTTP proxy to use for traffic to discovery service.
+ default: none
+ env variable: ETCD_DISCOVERY_PROXY
### --strict-reconfig-check
+ Reject reconfiguration requests that would cause quorum loss.
+ default: false
+ env variable: ETCD_STRICT_RECONFIG_CHECK
## Proxy Flags
`--proxy` prefix flags configures etcd to run in [proxy mode][proxy].
### --proxy
+ Proxy mode setting ("off", "readonly" or "on").
+ default: "off"
+ env variable: ETCD_PROXY
### --proxy-failure-wait
+ Time (in milliseconds) an endpoint will be held in a failed state before being reconsidered for proxied requests.
+ default: 5000
+ env variable: ETCD_PROXY_FAILURE_WAIT
### --proxy-refresh-interval
+ Time (in milliseconds) of the endpoints refresh interval.
+ default: 30000
+ env variable: ETCD_PROXY_REFRESH_INTERVAL
### --proxy-dial-timeout
+ Time (in milliseconds) for a dial to timeout or 0 to disable the timeout
+ default: 1000
+ env variable: ETCD_PROXY_DIAL_TIMEOUT
### --proxy-write-timeout
+ Time (in milliseconds) for a write to timeout or 0 to disable the timeout.
+ default: 5000
+ env variable: ETCD_PROXY_WRITE_TIMEOUT
### --proxy-read-timeout
+ Time (in milliseconds) for a read to timeout or 0 to disable the timeout.
+ Don't change this value if you use watches because they are using long polling requests.
+ default: 0
+ env variable: ETCD_PROXY_READ_TIMEOUT
## Security Flags
The security flags help to [build a secure etcd cluster][security].
### --ca-file [DEPRECATED]
+ Path to the client server TLS CA file. `--ca-file ca.crt` could be replaced by `--trusted-ca-file ca.crt --client-cert-auth` and etcd will perform the same.
+ default: none
+ env variable: ETCD_CA_FILE
### --cert-file
+ Path to the client server TLS cert file.
+ default: none
+ env variable: ETCD_CERT_FILE
### --key-file
+ Path to the client server TLS key file.
+ default: none
+ env variable: ETCD_KEY_FILE
### --client-cert-auth
+ Enable client cert authentication.
+ default: false
+ env variable: ETCD_CLIENT_CERT_AUTH
### --trusted-ca-file
+ Path to the client server TLS trusted CA key file.
+ default: none
+ env variable: ETCD_TRUSTED_CA_FILE
### --peer-ca-file [DEPRECATED]
+ Path to the peer server TLS CA file. `--peer-ca-file ca.crt` could be replaced by `--peer-trusted-ca-file ca.crt --peer-client-cert-auth` and etcd will perform the same.
+ default: none
+ env variable: ETCD_PEER_CA_FILE
### --peer-cert-file
+ Path to the peer server TLS cert file.
+ default: none
+ env variable: ETCD_PEER_CERT_FILE
### --peer-key-file
+ Path to the peer server TLS key file.
+ default: none
+ env variable: ETCD_PEER_KEY_FILE
### --peer-client-cert-auth
+ Enable peer client cert authentication.
+ default: false
+ env variable: ETCD_PEER_CLIENT_CERT_AUTH
### --peer-trusted-ca-file
+ Path to the peer server TLS trusted CA file.
+ default: none
+ env variable: ETCD_PEER_TRUSTED_CA_FILE
## Logging Flags
### --debug
+ Drop the default log level to DEBUG for all subpackages.
+ default: false (INFO for all packages)
+ env variable: ETCD_DEBUG
### --log-package-levels
+ Set individual etcd subpackages to specific log levels. An example being `etcdserver=WARNING,security=DEBUG`
+ default: none (INFO for all packages)
+ env variable: ETCD_LOG_PACKAGE_LEVELS
## Unsafe Flags
Please be CAUTIOUS when using unsafe flags because it will break the guarantees given by the consensus protocol.
For example, it may panic if other members in the cluster are still alive.
Follow the instructions when using these flags.
### --force-new-cluster
+ Force to create a new one-member cluster. It commits configuration changes forcing to remove all existing members in the cluster and add itself. It needs to be set to [restore a backup][restore].
+ default: false
+ env variable: ETCD_FORCE_NEW_CLUSTER
## Experimental Flags
### --experimental-v3demo
+ Enable experimental [v3 demo API][rfc-v3].
+ default: false
+ env variable: ETCD_EXPERIMENTAL_V3DEMO
## Miscellaneous Flags
### --version
+ Print the version and exit.
+ default: false
## Profiling flags
### --enable-pprof
+ Enable runtime profiling data via HTTP server. Address is at client URL + "/debug/pprof"
+ default: false
[build-cluster]: clustering.md#static
[reconfig]: runtime-configuration.md
[discovery]: clustering.md#discovery
[iana-ports]: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=etcd
[proxy]: proxy.md
[reconfig]: runtime-configuration.md
[restore]: admin_guide.md#restoring-a-backup
[rfc-v3]: rfc/v3api.md
[security]: security.md
[systemd-intro]: http://freedesktop.org/wiki/Software/systemd/
[tuning]: tuning.md#time-parameters
# Etcd Configuration
## Node Configuration
Individual node configuration options can be set in three places:
1. Command line flags
2. Environment variables
3. Configuration file
Options set on the command line take precedence over all other sources.
Options set in environment variables take precedence over options set in
configuration files.
## Cluster Configuration
Cluster-wide settings are configured via the `/config` admin endpoint and additionally in the configuration file. Values contained in the configuration file will seed the cluster setting with the provided value. After the cluster is running, only the admin endpoint is used.
The full documentation is contained in the [API docs](https://github.com/coreos/etcd/blob/master/Documentation/api.md#cluster-config).
* `activeSize` - the maximum number of peers that can participate in the consensus protocol. Other peers will join as standbys.
* `removeDelay` - the minimum time in seconds that a machine has been observed to be unresponsive before it is removed from the cluster.
* `syncInterval` - the amount of time in seconds between cluster sync when it runs in standby mode.
## Command Line Flags
### Required
* `-name` - The node name. Defaults to a UUID.
### Optional
* `-addr` - The advertised public hostname:port for client communication. Defaults to `127.0.0.1:4001`.
* `-discovery` - A URL to use for discovering the peer list. (i.e `"https://discovery.etcd.io/your-unique-key"`).
* `-http-read-timeout` - The number of seconds before an HTTP read operation is timed out.
* `-http-write-timeout` - The number of seconds before an HTTP write operation is timed out.
* `-bind-addr` - The listening hostname for client communication. Defaults to advertised IP.
* `-peers` - A comma separated list of peers in the cluster (i.e `"203.0.113.101:7001,203.0.113.102:7001"`).
* `-peers-file` - The file path containing a comma separated list of peers in the cluster.
* `-ca-file` - The path of the client CAFile. Enables client cert authentication when present.
* `-cert-file` - The cert file of the client.
* `-key-file` - The key file of the client.
* `-config` - The path of the etcd configuration file. Defaults to `/etc/etcd/etcd.conf`.
* `-cors` - A comma separated white list of origins for cross-origin resource sharing.
* `-cpuprofile` - The path to a file to output CPU profile data. Enables CPU profiling when present.
* `-data-dir` - The directory to store log and snapshot. Defaults to the current working directory.
* `-max-result-buffer` - The max size of result buffer. Defaults to `1024`.
* `-max-retry-attempts` - The max retry attempts when trying to join a cluster. Defaults to `3`.
* `-peer-addr` - The advertised public hostname:port for server communication. Defaults to `127.0.0.1:7001`.
* `-peer-bind-addr` - The listening hostname for server communication. Defaults to advertised IP.
* `-peer-ca-file` - The path of the CAFile. Enables client/peer cert authentication when present.
* `-peer-cert-file` - The cert file of the server.
* `-peer-key-file` - The key file of the server.
* `-peer-election-timeout` - The number of milliseconds to wait before the leader is declared unhealthy.
* `-peer-heartbeat-interval` - The number of milliseconds in between heartbeat requests
* `-snapshot=false` - Disable log snapshots. Defaults to `true`.
* `-cluster-active-size` - The expected number of instances participating in the consensus protocol. Only applied if the etcd instance is the first peer in the cluster.
* `-cluster-remove-delay` - The number of seconds before one node is removed from the cluster since it cannot be connected at all. Only applied if the etcd instance is the first peer in the cluster.
* `-cluster-sync-interval` - The number of seconds between synchronization for standby-mode instance with the cluster. Only applied if the etcd instance is the first peer in the cluster.
* `-v` - Enable verbose logging. Defaults to `false`.
* `-vv` - Enable very verbose logging. Defaults to `false`.
* `-version` - Print the version and exit.
## Configuration File
The etcd configuration file is written in [TOML](https://github.com/mojombo/toml)
and read from `/etc/etcd/etcd.conf` by default.
```TOML
addr = "127.0.0.1:4001"
bind_addr = "127.0.0.1:4001"
ca_file = ""
cert_file = ""
cors = []
cpu_profile_file = ""
data_dir = "."
discovery = "http://etcd.local:4001/v2/keys/_etcd/registry/examplecluster"
http_read_timeout = 10
http_write_timeout = 10
key_file = ""
peers = []
peers_file = ""
max_cluster_size = 9
max_result_buffer = 1024
max_retry_attempts = 3
name = "default-name"
snapshot = false
verbose = false
very_verbose = false
[peer]
addr = "127.0.0.1:7001"
bind_addr = "127.0.0.1:7001"
ca_file = ""
cert_file = ""
key_file = ""
[cluster]
active_size = 9
remove_delay = 1800.0
sync_interval = 5.0
```
## Environment Variables
* `ETCD_ADDR`
* `ETCD_BIND_ADDR`
* `ETCD_CA_FILE`
* `ETCD_CERT_FILE`
* `ETCD_CORS_ORIGINS`
* `ETCD_CONFIG`
* `ETCD_CPU_PROFILE_FILE`
* `ETCD_DATA_DIR`
* `ETCD_DISCOVERY`
* `ETCD_CLUSTER_HTTP_READ_TIMEOUT`
* `ETCD_CLUSTER_HTTP_WRITE_TIMEOUT`
* `ETCD_KEY_FILE`
* `ETCD_PEERS`
* `ETCD_PEERS_FILE`
* `ETCD_MAX_CLUSTER_SIZE`
* `ETCD_MAX_RESULT_BUFFER`
* `ETCD_MAX_RETRY_ATTEMPTS`
* `ETCD_NAME`
* `ETCD_SNAPSHOT`
* `ETCD_VERBOSE`
* `ETCD_VERY_VERBOSE`
* `ETCD_PEER_ADDR`
* `ETCD_PEER_BIND_ADDR`
* `ETCD_PEER_CA_FILE`
* `ETCD_PEER_CERT_FILE`
* `ETCD_PEER_KEY_FILE`
* `ETCD_PEER_ELECTION_TIMEOUT`
* `ETCD_CLUSTER_ACTIVE_SIZE`
* `ETCD_CLUSTER_REMOVE_DELAY`
* `ETCD_CLUSTER_SYNC_INTERVAL`

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# Debugging etcd
Diagnosing issues in a distributed application is hard.
etcd will help as much as it can - just enable these debug features using the CLI flag `-trace=*` or the config option `trace=*`.
## Logging
Log verbosity can be increased to the max using either the `-vvv` CLI flag or the `very_very_verbose=true` config option.
The only supported logging mode is to stdout.
## Metrics
etcd itself can generate a set of metrics.
These metrics represent many different internal data points that can be helpful when debugging etcd servers.
#### Metrics reference
Each individual metric name is prefixed with `etcd.<NAME>`, where \<NAME\> is the configured name of the etcd server.
* `timer.appendentries.handle`: amount of time a peer takes to process an AppendEntriesRequest from the POV of the peer itself
* `timer.peer.<PEER>.heartbeat`: amount of time a peer heartbeat operation takes from the POV of the leader that initiated that operation for peer \<PEER\>
* `timer.command.<COMMAND>`: amount of time a given command took to be processed through the local server's raft state machine. This does not include time waiting on locks.
#### Fetching metrics over HTTP
Once tracing has been enabled on a given etcd server, all metric data is available at the server's `/debug/metrics` HTTP endpoint (i.e. `http://127.0.0.1:4001/debug/metrics`).
Executing a GET HTTP command against the metrics endpoint will yield the current state of all metrics in the etcd server.
#### Sending metrics to Graphite
etcd supports [Graphite's Carbon plaintext protocol](https://graphite.readthedocs.org/en/latest/feeding-carbon.html#the-plaintext-protocol) - a TCP wire protocol designed for shipping metric data to an aggregator.
To send metrics to a Graphite endpoint using this protocol, use of the `-graphite-host` CLI flag or the `graphite_host` config option (i.e. `graphite_host=172.17.0.19:2003`).
See an [example graphite deploy script](https://github.com/coreos/etcd/contrib/graphite).
#### Generating additional metrics with Collectd
[Collectd](http://collectd.org/documentation.shtml) gathers metrics from the host running etcd.
While these aren't metrics generated by etcd itself, it can be invaluable to compare etcd's view of the world to that of a separate process running next to etcd.
See an [example collectd deploy script](https://github.com/coreos/etcd/contrib/collectd).
## Profiling
etcd exposes profiling information from the Go pprof package over HTTP.
The basic browsable interface is served by etcd at the `/debug/pprof` HTTP endpoint (i.e. `http://127.0.0.1:4001/debug/pprof`).
For more information on using profiling tools, see http://blog.golang.org/profiling-go-programs.
**NOTE**: In the following examples you need to ensure that the `./bin/etcd` is identical to the `./bin/etcd` that you are targeting (same git hash, arch, platform, etc).
#### Heap memory profile
```
go tool pprof ./bin/etcd http://127.0.0.1:4001/debug/pprof/heap
```
#### CPU profile
```
go tool pprof ./bin/etcd http://127.0.0.1:4001/debug/pprof/profile
```
#### Blocked goroutine profile
```
go tool pprof ./bin/etcd http://127.0.0.1:4001/debug/pprof/block
```

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## Cluster Finding Process
Peer discovery uses the following sources in this order: log data in `-data-dir`, `-discovery` and `-peers`.
If log data is provided, etcd will concatenate possible peers from three sources: the log data, the `-discovery` option, and `-peers`. Then it tries to join cluster through them one by one. If all connection attempts fail (which indicates that the majority of the cluster is currently down), it will restart itself based on the log data, which helps the cluster to recover from a full outage.
Without log data, the instance is assumed to be a brand new one. If possible targets are provided by `-discovery` and `-peers`, etcd will make a best effort attempt to join them, and if none is reachable it will exit. Otherwise, if no `-discovery` or `-peers` option is provided, a new cluster will always be started.
This ensures that users can always restart the node safely with the same command (without --force), and etcd will either reconnect to the old cluster if it is still running or recover its cluster from a outage.
## Logical Workflow
Start an etcd machine:
```
If log data is given:
Try to join via peers in previous cluster
Try to join via peers found in discover URL
Try to join via peers in peer list
Restart the previous cluster which is down
return
If discover URL is given:
Fetch peers through discover URL
If Success:
Join via peers found
return
If peer list is given:
Join as follower via peers in peer list
return
Start as the leader of a new cluster
```

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## Standbys
Adding peers in an etcd cluster adds network, CPU, and disk overhead to the leader since each one requires replication.
Peers primarily provide resiliency in the event of a leader failure but the benefit of more failover nodes decreases as the cluster size increases.
A lightweight alternative is the standby.
Standbys are a way for an etcd node to forward requests along to the cluster but the standbys are not part of the Raft cluster themselves.
This provides an easier API for local applications while reducing the overhead required by a regular peer node.
Standbys also act as standby nodes in the event that a peer node in the cluster has not recovered after a long duration.
## Configuration Parameters
There are three configuration parameters used by standbys: active size, remove delay and standby sync interval.
The active size specifies a target size for the number of peers in the cluster.
If there are not enough peers to meet the active size, standbys will send join requests until the peer count is equal to the active size.
If there are more peers than the target active size then peers are removed by the leader and will become standbys.
The remove delay specifies how long the cluster should wait before removing a dead peer.
By default this is 30 minutes.
If a peer is inactive for 30 minutes then the peer is removed.
The standby sync interval specifies the synchronization interval of standbys with the cluster.
By default this is 5 seconds.
After each interval, standbys synchronize information with cluster.
## Logical Workflow
### Start a etcd machine
#### Main logic
```
If find existing standby cluster info:
Goto standby loop
Find cluster as required
If determine to start peer server:
Goto peer loop
Else:
Goto standby loop
Peer loop:
Start peer mode
If running:
Wait for stop
Goto standby loop
Standby loop:
Start standby mode
If running:
Wait for stop
Goto peer loop
```
#### [Cluster finding logic][cluster-finding.md]
#### Join request logic:
```
Fetch machine info
If cannot match version:
return false
If active size <= peer count:
return false
If it has existed in the cluster:
return true
If join request fails:
return false
return true
```
**Note**
1. [TODO] The running mode cannot be determined by log, because the log may be outdated. But the log could be used to estimate its state.
2. Even if sync cluster fails, it will restart still for recovery from full outage.
#### Peer mode start logic
```
Start raft server
Start other helper routines
```
#### Peer mode auto stop logic
```
When removed from the cluster:
Stop raft server
Stop other helper routines
```
#### Standby mode run logic
```
Loop:
Sleep for some time
Sync cluster, and write cluster info into disk
Check active size and send join request if needed
If succeed:
Clear cluster info from disk
Return
```
#### Serve Requests as Standby
Return '404 Page Not Found' always on peer address. This is because peer address is used for raft communication and cluster management, which should not be used in standby mode.
Serve requests from client:
```
Redirect all requests to client URL of leader
```
**Note**
1. The leader here implies the one in raft cluster when doing the latest successful synchronization.
2. [IDEA] We could extend HTTP Redirect to multiple possible targets.
### Join Request Handling
```
If machine has existed in the cluster:
Return
If peer count < active size:
Add peer
Increase peer count
```
### Remove Request Handling
```
If machine exists in the cluster:
Remove peer
Decrease peer count
```
## Cluster Monitor Logic
### Active Size Monitor:
This is only run by current cluster leader.
```
Loop:
Sleep for some time
If peer count > active size:
Remove randomly selected peer
```
### Peer Activity Monitor
This is only run by current cluster leader.
```
Loop:
Sleep for some time
For each peer:
If peer last activity time > remove delay:
Remove the peer
Goto Loop
```
## Cluster Cases
### Create Cluster with Thousands of Instances
First few machines run in peer mode.
All the others check the status of the cluster and run in standby mode.
### Recover from full outage
Machines with log data restart with join failure.
Machines in peer mode recover heartbeat between each other.
Machines in standby mode always sync the cluster. If sync fails, it uses the first address from data log as redirect target.
### Kill one peer machine
Leader of the cluster lose the connection with the peer.
When the time exceeds remove delay, it removes the peer from the cluster.
Machine in standby mode finds one available place of the cluster. It sends join request and joins the cluster.
**Note**
1. [TODO] Machine which was divided from majority and was removed from the cluster will distribute running of the cluster if the new node uses the same name.
### Kill one standby machine
No change for the cluster.
## Cons
1. New instance cannot join immediately after one peer is kicked out of the cluster, because the leader doesn't know the info about the standby instances.
2. It may introduce join collision
3. Cluster needs a good interval setting to balance the join delay and join collision.
## Future Attack Plans
1. Based on heartbeat miss and remove delay, standby could adjust its next check time.
2. Preregister the promotion target when heartbeat miss happens.
3. Get the estimated cluster size from the check happened in the sync interval, and adjust sync interval dynamically.
4. Accept join requests based on active size and alive peers.

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# etcd release guide
The guide talks about how to release a new version of etcd.
The procedure includes some manual steps for sanity checking but it can probably be further scripted. Please keep this document up-to-date if you want to make changes to the release process.
## Prepare Release
Set desired version as environment variable for following steps. Here is an example to release 2.3.0:
```
export VERSION=v2.3.0
export PREV_VERSION=v2.2.5
```
All releases version numbers follow the format of [semantic versioning 2.0.0](http://semver.org/).
### Major, Minor Version Release, or its Pre-release
- Ensure the relevant milestone on GitHub is complete. All referenced issues should be closed, or moved elsewhere.
- Remove this release from [roadmap](https://github.com/coreos/etcd/blob/master/ROADMAP.md), if necessary.
- Ensure the latest upgrade documentation is available.
- Bump [hardcoded MinClusterVerion in the repository](https://github.com/coreos/etcd/blob/master/version/version.go#L29), if necessary.
- Add feature capability maps for the new version, if necessary.
### Patch Version Release
- Discuss about commits that are backported to the patch release. The commits should not include merge commits.
- Cherry-pick these commits starting from the oldest one into stable branch.
## Write Release Note
- Write introduction for the new release. For example, what major bug we fix, what new features we introduce or what performance improvement we make.
- Write changelog for the last release. ChangeLog should be straightforward and easy to understand for the end-user.
- Put `[GH XXXX]` at the head of change line to reference Pull Request that introduces the change. Moreover, add a link on it to jump to the Pull Request.
## Tag Version
- Bump [hardcoded Version in the repository](https://github.com/coreos/etcd/blob/master/version/version.go#L30) to the latest version `${VERSION}`.
- Ensure all tests on CI system are passed.
- Manually check etcd is buildable in Linux, Darwin and Windows.
- Manually check upgrade etcd cluster of previous minor version works well.
- Manually check new features work well.
- Add a signed tag through `git tag -s ${VERSION}`.
- Sanity check tag correctness through `git show tags/$VERSION`.
- Push the tag to GitHub through `git push origin tags/$VERSION`. This assumes `origin` corresponds to "https://github.com/coreos/etcd".
## Build Release Binaries and Images
- Ensure `actool` is available, or installing it through `go get github.com/appc/spec/actool`.
- Ensure `docker` is available.
Run release script in root directory:
```
./scripts/release.sh ${VERSION}
```
It generates all release binaries and images under directory ./release.
## Sign Binaries and Images
etcd project key must be used to sign the generated binaries and images.`$SUBKEYID` is the key ID of etcd project Yubikey. Connect the key and run `gpg2 --card-status` to get the ID.
The following commands are used for public release sign:
```
cd release
for i in etcd-*{.zip,.tar.gz}; do gpg2 --default-key $SUBKEYID --output ${i}.asc --detach-sign ${i}; done
for i in etcd-*{.zip,.tar.gz}; do gpg2 --verify ${i}.asc ${i}; done
```
## Publish Release Page in GitHub
- Set release title as the version name.
- Follow the format of previous release pages.
- Attach the generated binaries, aci image and signatures.
- Select whether it is a pre-release.
- Publish the release!
## Publish Docker Image in Quay.io
- Push docker image:
```
docker login quay.io
docker push quay.io/coreos/etcd:${VERSION}
```
- Add `latest` tag to the new image on [quay.io](https://quay.io/repository/coreos/etcd?tag=latest&tab=tags) if this is a stable release.
## Announce to etcd-dev Googlegroup
- Follow the format of [previous release emails](https://groups.google.com/forum/#!forum/etcd-dev).
- Make sure to include a list of authors that contributed since the previous release - something like the following might be handy:
```
git log ...${PREV_VERSION} --pretty=format:"%an" | sort | uniq | tr '\n' ',' | sed -e 's#,#, #g' -e 's#, $##'
```
- Send email to etcd-dev@googlegroups.com
## Post Release
- Create new stable branch through `git push origin ${VERSION_MAJOR}.${VERSION_MINOR}` if this is a major stable release. This assumes `origin` corresponds to "https://github.com/coreos/etcd".
- Bump [hardcoded Version in the repository](https://github.com/coreos/etcd/blob/master/version/version.go#L30) to the version `${VERSION}+git`.

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# Development tools
## Vagrant
For fast start you can use Vagrant. `vagrant up` will make etcd build and running on virtual machine. Required Vagrant version is 1.5.0.
Next lets set a single key and then retrieve it:
```
curl -L http://127.0.0.1:4001/v2/keys/mykey -XPUT -d value="this is awesome"
curl -L http://127.0.0.1:4001/v2/keys/mykey
```

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# Discovery Protocol
Starting a new etcd cluster can be painful since each machine needs to know of at least one live machine in the cluster. If you are trying to bring up a new cluster all at once, say using an AWS cloud formation, you also need to coordinate who will be the initial cluster leader. The discovery protocol uses an existing running etcd cluster to start a second etcd cluster.
To use this feature you add the command line flag `-discovery` to your etcd args. In this example we will use `http://example.com/v2/keys/_etcd/registry` as the URL prefix.
## The Protocol
By convention the etcd discovery protocol uses the key prefix `_etcd/registry`. A full URL to the keyspace will be `http://example.com/v2/keys/_etcd/registry`.
### Creating a New Cluster
Generate a unique token that will identify the new cluster. This will be used as a key prefix in the following steps. An easy way to do this is to use uuidgen:
```
UUID=$(uuidgen)
```
### Bringing up Machines
Now that you have your cluster ID you can start bringing up machines. Every machine will follow this protocol internally in etcd if given a `-discovery`.
### Registering your Machine
The first thing etcd must do is register your machine. This is done by using the machine name (from the `-name` arg) and posting it with a long TTL to the given key.
```
curl -X PUT "http://example.com/v2/keys/_etcd/registry/${UUID}/${etcd_machine_name}?ttl=604800" -d value=${peer_addr}
```
### Discovering Peers
Now that this etcd machine is registered it must discover its peers.
But, the tricky bit of starting a new cluster is that one machine needs to assume the initial role of leader and will have no peers. To figure out if another machine has already started the cluster etcd needs to create the `_state` key and set its value to "started":
```
curl -X PUT "http://example.com/v2/keys/_etcd/registry/${UUID}/_state?prevExist=false" -d value=started
```
If this returns a `200 OK` response then this machine is the initial leader and should start with no peers configured. If, however, this returns a `412 Precondition Failed` then you need to find all of the registered peers:
```
curl -X GET "http://example.com/v2/keys/_etcd/registry/${UUID}?recursive=true"
```
```
{
"action": "get",
"node": {
"createdIndex": 11,
"dir": true,
"key": "/_etcd/registry/9D4258A5-A1D3-4074-8837-31C1E091131D",
"modifiedIndex": 11,
"nodes": [
{
"createdIndex": 16,
"expiration": "2014-02-03T13:19:57.631253589-08:00",
"key": "/_etcd/registry/9D4258A5-A1D3-4074-8837-31C1E091131D/peer1",
"modifiedIndex": 16,
"ttl": 604765,
"value": "127.0.0.1:7001"
},
{
"createdIndex": 17,
"expiration": "2014-02-03T13:19:57.631253589-08:00",
"key": "/_etcd/registry/9D4258A5-A1D3-4074-8837-31C1E091131D/peer2",
"modifiedIndex": 17,
"ttl": 604765,
"value": "127.0.0.1:7002"
}
]
}
}
```
Using this information you can connect to the rest of the peers in the cluster.
### Heartbeating
At this point etcd will start heart beating to your registration URL. The
protocol uses a heartbeat so permanently deleted nodes get slowly removed from
the discovery information cluster.
The heartbeat interval is about once per day and the TTL is one week. This
should give a sufficiently wide window to protect against a discovery service
taking a temporary outage yet provide adequate cleanup.

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# Discovery Service Protocol
Discovery service protocol helps new etcd member to discover all other members in cluster bootstrap phase using a shared discovery URL.
Discovery service protocol is _only_ used in cluster bootstrap phase, and cannot be used for runtime reconfiguration or cluster monitoring.
The protocol uses a new discovery token to bootstrap one _unique_ etcd cluster. Remember that one discovery token can represent only one etcd cluster. As long as discovery protocol on this token starts, even if it fails halfway, it must not be used to bootstrap another etcd cluster.
The rest of this article will walk through the discovery process with examples that correspond to a self-hosted discovery cluster. The public discovery service, discovery.etcd.io, functions the same way, but with a layer of polish to abstract away ugly URLs, generate UUIDs automatically, and provide some protections against excessive requests. At its core, the public discovery service still uses an etcd cluster as the data store as described in this document.
## The Protocol Workflow
The idea of discovery protocol is to use an internal etcd cluster to coordinate bootstrap of a new cluster. First, all new members interact with discovery service and help to generate the expected member list. Then each new member bootstraps its server using this list, which performs the same functionality as -initial-cluster flag.
In the following example workflow, we will list each step of protocol in curl format for ease of understanding.
By convention the etcd discovery protocol uses the key prefix `_etcd/registry`. If `http://example.com` hosts an etcd cluster for discovery service, a full URL to discovery keyspace will be `http://example.com/v2/keys/_etcd/registry`. We will use this as the URL prefix in the example.
### Creating a New Discovery Token
Generate a unique token that will identify the new cluster. This will be used as a unique prefix in discovery keyspace in the following steps. An easy way to do this is to use `uuidgen`:
```
UUID=$(uuidgen)
```
### Specifying the Expected Cluster Size
You need to specify the expected cluster size for this discovery token. The size is used by the discovery service to know when it has found all members that will initially form the cluster.
```
curl -X PUT http://example.com/v2/keys/_etcd/registry/${UUID}/_config/size -d value=${cluster_size}
```
Usually the cluster size is 3, 5 or 7. Check [optimal cluster size][cluster-size] for more details.
### Bringing up etcd Processes
Now that you have your discovery URL, you can use it as `-discovery` flag and bring up etcd processes. Every etcd process will follow this next few steps internally if given a `-discovery` flag.
### Registering itself
The first thing for etcd process is to register itself into the discovery URL as a member. This is done by creating member ID as a key in the discovery URL.
```
curl -X PUT http://example.com/v2/keys/_etcd/registry/${UUID}/${member_id}?prevExist=false -d value="${member_name}=${member_peer_url_1}&${member_name}=${member_peer_url_2}"
```
### Checking the Status
It checks the expected cluster size and registration status in discovery URL, and decides what the next action is.
```
curl -X GET http://example.com/v2/keys/_etcd/registry/${UUID}/_config/size
curl -X GET http://example.com/v2/keys/_etcd/registry/${UUID}
```
If registered members are still not enough, it will wait for left members to appear.
If the number of registered members is bigger than the expected size N, it treats the first N registered members as the member list for the cluster. If the member itself is in the member list, the discovery procedure succeeds and it fetches all peers through the member list. If it is not in the member list, the discovery procedure finishes with the failure that the cluster has been full.
In etcd implementation, the member may check the cluster status even before registering itself. So it could fail quickly if the cluster has been full.
### Waiting for All Members
The wait process is described in detail in the [etcd API documentation][api].
```
curl -X GET http://example.com/v2/keys/_etcd/registry/${UUID}?wait=true&waitIndex=${current_etcd_index}
```
It keeps waiting until finding all members.
## Public Discovery Service
CoreOS Inc. hosts a public discovery service at https://discovery.etcd.io/ , which provides some nice features for ease of use.
### Mask Key Prefix
Public discovery service will redirect `https://discovery.etcd.io/${UUID}` to etcd cluster behind for the key at `/v2/keys/_etcd/registry`. It masks register key prefix for short and readable discovery url.
### Get new token
```
GET /new
Sent query:
size=${cluster_size}
Possible status codes:
200 OK
400 Bad Request
200 Body:
generated discovery url
```
The generation process in the service follows the steps from [Creating a New Discovery Token][new-discovery-token] to [Specifying the Expected Cluster Size][expected-cluster-size].
### Check Discovery Status
```
GET /${UUID}
```
You can check the status for this discovery token, including the machines that have been registered, by requesting the value of the UUID.
### Open-source repository
The repository is located at https://github.com/coreos/discovery.etcd.io. You could use it to build your own public discovery service.
[api]: api.md#waiting-for-a-change
[cluster-size]: admin_guide.md#optimal-cluster-size
[expected-cluster-size]: #specifying-the-expected-cluster-size
[new-discovery-token]: #creating-a-new-discovery-token

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# Running etcd under Docker
The following guide will show you how to run etcd under Docker using the [static bootstrap process](clustering.md#static).
## Running etcd in standalone mode
In order to expose the etcd API to clients outside of the Docker host you'll need use the host IP address when configuring etcd.
```
export HostIP="192.168.12.50"
```
The following `docker run` command will expose the etcd client API over ports 4001 and 2379, and expose the peer port over 2380.
This will run the latest release version of etcd. You can specify version if needed (e.g. `quay.io/coreos/etcd:v2.2.0`).
```
docker run -d -v /usr/share/ca-certificates/:/etc/ssl/certs -p 4001:4001 -p 2380:2380 -p 2379:2379 \
--name etcd quay.io/coreos/etcd \
-name etcd0 \
-advertise-client-urls http://${HostIP}:2379,http://${HostIP}:4001 \
-listen-client-urls http://0.0.0.0:2379,http://0.0.0.0:4001 \
-initial-advertise-peer-urls http://${HostIP}:2380 \
-listen-peer-urls http://0.0.0.0:2380 \
-initial-cluster-token etcd-cluster-1 \
-initial-cluster etcd0=http://${HostIP}:2380 \
-initial-cluster-state new
```
Configure etcd clients to use the Docker host IP and one of the listening ports from above.
```
etcdctl -C http://192.168.12.50:2379 member list
```
```
etcdctl -C http://192.168.12.50:4001 member list
```
## Running a 3 node etcd cluster
Using Docker to setup a multi-node cluster is very similar to the standalone mode configuration.
The main difference being the value used for the `-initial-cluster` flag, which must contain the peer urls for each etcd member in the cluster.
### etcd0
```
docker run -d -v /usr/share/ca-certificates/:/etc/ssl/certs -p 4001:4001 -p 2380:2380 -p 2379:2379 \
--name etcd quay.io/coreos/etcd \
-name etcd0 \
-advertise-client-urls http://192.168.12.50:2379,http://192.168.12.50:4001 \
-listen-client-urls http://0.0.0.0:2379,http://0.0.0.0:4001 \
-initial-advertise-peer-urls http://192.168.12.50:2380 \
-listen-peer-urls http://0.0.0.0:2380 \
-initial-cluster-token etcd-cluster-1 \
-initial-cluster etcd0=http://192.168.12.50:2380,etcd1=http://192.168.12.51:2380,etcd2=http://192.168.12.52:2380 \
-initial-cluster-state new
```
### etcd1
```
docker run -d -v /usr/share/ca-certificates/:/etc/ssl/certs -p 4001:4001 -p 2380:2380 -p 2379:2379 \
--name etcd quay.io/coreos/etcd \
-name etcd1 \
-advertise-client-urls http://192.168.12.51:2379,http://192.168.12.51:4001 \
-listen-client-urls http://0.0.0.0:2379,http://0.0.0.0:4001 \
-initial-advertise-peer-urls http://192.168.12.51:2380 \
-listen-peer-urls http://0.0.0.0:2380 \
-initial-cluster-token etcd-cluster-1 \
-initial-cluster etcd0=http://192.168.12.50:2380,etcd1=http://192.168.12.51:2380,etcd2=http://192.168.12.52:2380 \
-initial-cluster-state new
```
### etcd2
```
docker run -d -v /usr/share/ca-certificates/:/etc/ssl/certs -p 4001:4001 -p 2380:2380 -p 2379:2379 \
--name etcd quay.io/coreos/etcd \
-name etcd2 \
-advertise-client-urls http://192.168.12.52:2379,http://192.168.12.52:4001 \
-listen-client-urls http://0.0.0.0:2379,http://0.0.0.0:4001 \
-initial-advertise-peer-urls http://192.168.12.52:2380 \
-listen-peer-urls http://0.0.0.0:2380 \
-initial-cluster-token etcd-cluster-1 \
-initial-cluster etcd0=http://192.168.12.50:2380,etcd1=http://192.168.12.51:2380,etcd2=http://192.168.12.52:2380 \
-initial-cluster-state new
```
Once the cluster has been bootstrapped etcd clients can be configured with a list of etcd members:
```
etcdctl -C http://192.168.12.50:2379,http://192.168.12.51:2379,http://192.168.12.52:2379 member list
```

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# Error Code
Error Code
======
This document describes the error code used in key space '/v2/keys'. Feel free to import 'github.com/coreos/etcd/error' to use.
This document describes the error code in **Etcd** project.
It's categorized into four groups:
- Command Related Error
| name | code | strerror |
|----------------------|------|-----------------------|
| EcodeKeyNotFound | 100 | "Key not found" |
| EcodeTestFailed | 101 | "Compare failed" |
| EcodeNotFile | 102 | "Not a file" |
| EcodeNotDir | 104 | "Not a directory" |
| EcodeNodeExist | 105 | "Key already exists" |
| EcodeRootROnly | 107 | "Root is read only" |
| EcodeDirNotEmpty | 108 | "Directory not empty" |
- Post Form Related Error
| name | code | strerror |
|--------------------------|------|------------------------------------------------|
| EcodePrevValueRequired | 201 | "PrevValue is Required in POST form" |
| EcodeTTLNaN | 202 | "The given TTL in POST form is not a number" |
| EcodeIndexNaN | 203 | "The given index in POST form is not a number" |
| EcodeInvalidField | 209 | "Invalid field" |
| EcodeInvalidForm | 210 | "Invalid POST form" |
- Raft Related Error
| name | code | strerror |
|-------------------|------|--------------------------|
| EcodeRaftInternal | 300 | "Raft Internal Error" |
| EcodeLeaderElect | 301 | "During Leader Election" |
- Etcd Related Error
| name | code | strerror |
|-------------------------|------|--------------------------------------------------------|
| EcodeWatcherCleared | 400 | "watcher is cleared due to etcd recovery" |
| EcodeEventIndexCleared | 401 | "The event in requested index is outdated and cleared" |
Error code corresponding strerror
------
const (
EcodeKeyNotFound = 100
EcodeTestFailed = 101
EcodeNotFile = 102
EcodeNoMorePeer = 103
EcodeNotDir = 104
EcodeNodeExist = 105
EcodeKeyIsPreserved = 106
EcodeRootROnly = 107
EcodeValueRequired = 200
EcodePrevValueRequired = 201
EcodeTTLNaN = 202
EcodeIndexNaN = 203
EcodeRaftInternal = 300
EcodeLeaderElect = 301
EcodeWatcherCleared = 400
EcodeEventIndexCleared = 401
)
// command related errors
errors[100] = "Key Not Found"
errors[101] = "Test Failed" //test and set
errors[102] = "Not A File"
errors[103] = "Reached the max number of peers in the cluster"
errors[104] = "Not A Directory"
errors[105] = "Already exists" // create
errors[106] = "The prefix of given key is a keyword in etcd"
errors[107] = "Root is read only"
// Post form related errors
errors[200] = "Value is Required in POST form"
errors[201] = "PrevValue is Required in POST form"
errors[202] = "The given TTL in POST form is not a number"
errors[203] = "The given index in POST form is not a number"
// raft related errors
errors[300] = "Raft Internal Error"
errors[301] = "During Leader Election"
// etcd related errors
errors[400] = "watcher is cleared due to etcd recovery"
errors[401] = "The event in requested index is outdated and cleared"

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#Etcd File System
## Structure
[TODO]
![alt text](./img/etcd_fs_structure.jpg "etcd file system structure")
## Node
In **etcd**, the **node** is the base from which the filesystem is constructed.
**etcd**'s file system is Unix-like with two kinds of nodes: file and directories.
- A **file node** has data associated with it.
- A **directory node** has child nodes associated with it.
All nodes, regardless of type, have the following attributes and operations:
### Attributes:
- **Expiration Time** [optional]
The node will be deleted when it expires.
- **ACL**
The path to the node's access control list.
### Operation:
- **Get** (path, recursive, sorted)
Get the content of the node
- If the node is a file, the data of the file will be returned.
- If the node is a directory, the child nodes of the directory will be returned.
- If recursive is true, it will recursively get the nodes of the directory.
- If sorted is true, the result will be sorted based on the path.
- **Create** (path, value[optional], ttl [optional])
Create a file. Create operation will help to create intermediate directories with no expiration time.
- If the file already exists, create will fail.
- If the value is given, set will create a file.
- If the value is not given, set will crate a directory.
- If ttl is given, the node will be deleted when it expires.
- **Update** (path, value[optional], ttl [optional])
Update the content of the node.
- If the value is given, the value of the key will be updated.
- If ttl is given, the expiration time of the node will be updated.
- **Delete** (path, recursive)
Delete the node of given path.
- If the node is a directory:
- If recursive is true, the operation will delete all nodes under the directory.
- If recursive is false, error will be returned.
- **TestAndSet** (path, prevValue [prevIndex], value, ttl)
Atomic *test and set* value to a file. If test succeeds, this operation will change the previous value of the file to the given value.
- If the prevValue is given, it will test against previous value of
the node.
- If the prevValue is empty, it will test if the node is not existing.
- If the prevValue is not empty, it will test if the prevValue is equal to the current value of the file.
- If the prevIndex is given, it will test if the create/last modified index of the node is equal to prevIndex.
- **Renew** (path, ttl)
Set the node's expiration time to (current time + ttl)
## ACL
### Theory
Etcd exports a Unix-like file system interface consisting of files and directories, collectively called nodes.
Each node has various meta-data, including three names of the access control lists used to control reading, writing and changing (change ACL names for the node).
We are storing the ACL names for nodes under a special *ACL* directory.
Each node has ACL name corresponding to one file within *ACL* dir.
Unless overridden, a node naturally inherits the ACL names of its parent directory on creation.
For each ACL name, it has three children: *R (Reading)*, *W (Writing)*, *C (Changing)*
Each permission is also a node. Under the node it contains the users who have this permission for the file referring to this ACL name.
### Example
[TODO]
### Diagram
[TODO]
### Interface
Testing permissions:
- (node *Node) get_perm()
- (node *Node) has_perm(perm string, user string)
Setting/Changing permissions:
- (node *Node) set_perm(perm string)
- (node *Node) change_ACLname(aclname string)
## User Group
[TODO]

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# FAQ
## 1) How come I can read an old version of the data when a majority of the members are down?
In situations where a client connects to a minority, etcd
favors by default availability over consistency. This means that even though
data might be “out of date”, it is still better to return something versus
nothing.
In order to confirm that a read is up to date with a majority of the cluster,
the client can use the `quorum=true` parameter on reads of keys. This means
that a majority of the cluster is checked on reads before returning the data,
otherwise the read will timeout and fail.
## 2) With quorum=false, doesnt this mean that if my client switched the member it was connected to, that it could experience a logical ordering where the cluster goes backwards in time?
Yes, but this could be handled at the etcd client implementation via
remembering the last seen index. The “index” is the cluster's single
irrevocable sequence of the entire modification history. The client could
remember the last seen index, and determine via comparing the index returned on
the GET whether or not the state of the key-value pair is before or after its
last seen state.
## 3) What happens if a watch is registered on a minority member?
The watch will stay untriggered, even as modifications are occurring in the
majority quorum. This is an open issue, and is being addressed in v3. There are
multiple ways to work around the watch trigger not firing.
1) build a signaling mechanism independent of etcd. This could be as simple as
a “pulse” to the client to reissue a GET with quorum=true for the most recent
version of the data.
2) poll on the `/v2/keys` endpoint and check that the raft-index is increasing every
timeout.
## 4) What is a proxy used for?
A proxy is a redirection server to the etcd cluster. The proxy handles the
redirection of a client to the current configuration of the etcd cluster. A
typical use case is to start a proxy on a machine, and on first boot up of the
proxy specify both the `--proxy` flag and the `--initial-cluster` flag.
From there, any etcdctl client that starts up automatically speaks to the local
proxy and the proxy redirects operations to the current configuration of the
cluster it was originally paired with.
In the v2 spec of etcd, proxies cannot be promoted to members of the cluster.
They also cannot be promoted to followers or at any point become part of the
replication of the etcd cluster itself.
## 5) How is cluster membership and health handled in etcd v2?
The design goal of etcd is that reconfiguration is simply an API, and health
monitoring and addition/removal of members is up to the individual application
and their integration with the reconfiguration API.
Thus, a member that is down, even infinitely, will never be automatically
removed from the etcd cluster member list.
This makes sense because it's usually an application level / administrative
action to determine whether a reconfiguration should happen based on health.
For more information, refer to the [runtime reconfiguration design document][runtime-reconf-design].
## 6) how does --endpoint work with etcdctl?
The `--endpoint` flag can specify any number of etcd cluster members in a comma
separated list. This list might be a subset, equal to, or more than the actual
etcd cluster member list itself.
If only one peer is specified via the `--endpoint` flag, the etcdctl discovers the
rest of the cluster via the member list of that one peer, and then it randomly
chooses a member to use. Again, the client can use the `quorum=true` flag on
reads, which will always fail when using a member in the minority.
If peers from multiple clusters are specified via the `--endpoint` flag, etcdctl
will randomly choose a peer, and the request will simply get routed to one of
the clusters. This is probably not what you want.
Note: --peers flag is now deprecated and --endpoint should be used instead,
as it might confuse users to give etcdctl a peerURL.
[runtime-reconf-design]: runtime-reconf-design.md

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# Glossary
This document defines the various terms used in etcd documentation, command line and source code.
## Node
Node is an instance of raft state machine.
It has a unique identification, and records other nodes' progress internally when it is the leader.
## Member
Member is an instance of etcd. It hosts a node, and provides service to clients.
## Cluster
Cluster consists of several members.
The node in each member follows raft consensus protocol to replicate logs. Cluster receives proposals from members, commits them and apply to local store.
## Peer
Peer is another member of the same cluster.
## Proposal
A proposal is a request (for example a write request, a configuration change request) that needs to go through raft protocol.
## Client
Client is a caller of the cluster's HTTP API.
## Machine (deprecated)
The alternative of Member in etcd before 2.0

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# FAQ
## Initial Bootstrapping UX
etcd initial bootstrapping is done via command line flags such as
`--initial-cluster` or `--discovery`. These flags can safely be left on the
command line after your cluster is running but they will be ignored if you have
a non-empty data dir. So, why did we decide to have this sort of odd UX?
One of the design goals of etcd is easy bringup of clusters using a one-shot
static configuration like AWS Cloud Formation, PXE booting, etc. Essentially we
want to describe several virtual machines and bring them all up at once into an
etcd cluster.
To achieve this sort of hands-free cluster bootstrap we had two other options:
**API to bootstrap**
This is problematic because it cannot be coordinated from a single service file
and we didn't want to have the etcd socket listening but unresponsive to
clients for an unbound period of time.
It would look something like this:
```
ExecStart=/usr/bin/etcd
ExecStartPost/usr/bin/etcd init localhost:2379 --cluster=
```
**etcd init subcommand**
```
etcd init --cluster='default=http://localhost:2380,default=http://localhost:7001'...
etcd init --discovery https://discovery-example.etcd.io/193e4
```
Then after running an init step you would execute `etcd`. This however
introduced problems: we now have to define a hand-off protocol between the etcd
init process and the etcd binary itself. This is hard to coordinate in a single
service file such as:
```
ExecStartPre=/usr/bin/etcd init --cluster=....
ExecStart=/usr/bin/etcd
```
There are several error cases:
0) Init has already run and the data directory is already configured
1) Discovery fails because of network timeout, etc
2) Discovery fails because the cluster is already full and etcd needs to fall back to proxy
3) Static cluster configuration fails because of conflict, misconfiguration or timeout
In hindsight we could have made this work by doing:
```
rc status
0 Init already ran
1 Discovery fails on network timeout, etc
0 Discovery fails for cluster full, coordinate via proxy state file
1 Static cluster configuration failed
```
Perhaps we can add the init command in a future version and deprecate if the UX
continues to confuse people.

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# Libraries and Tools
## Libraries and Tools
**Tools**
- [etcdctl](https://github.com/coreos/etcd/tree/master/etcdctl) - A command line client for etcd
- [etcd-backup](https://github.com/fanhattan/etcd-backup) - A powerful command line utility for dumping/restoring etcd - Supports v2
- [etcdctl](https://github.com/coreos/etcdctl) - A command line client for etcd
- [etcd-dump](https://npmjs.org/package/etcd-dump) - Command line utility for dumping/restoring etcd.
- [etcd-fs](https://github.com/xetorthio/etcd-fs) - FUSE filesystem for etcd
- [etcddir](https://github.com/rekby/etcddir) - Realtime sync etcd and local directory. Work with windows and linux.
- [etcd-browser](https://github.com/henszey/etcd-browser) - A web-based key/value editor for etcd using AngularJS
- [etcd-lock](https://github.com/datawisesystems/etcd-lock) - Master election & distributed r/w lock implementation using etcd - Supports v2
- [etcd-console](https://github.com/matishsiao/etcd-console) - A web-base key/value editor for etcd using PHP
- [etcd-viewer](https://github.com/nikfoundas/etcd-viewer) - An etcd key-value store editor/viewer written in Java
- [etcdtool](https://github.com/mickep76/etcdtool) - Export/Import/Edit etcd directory as JSON/YAML/TOML and Validate directory using JSON schema
- [etcd-rest](https://github.com/mickep76/etcd-rest) - Create generic REST API in Go using etcd as a backend with validation using JSON schema
- [etcdsh](https://github.com/kamilhark/etcdsh) - A command line client with support of command history and tab completion. Supports v2
**Go libraries**
- [etcd/client](https://github.com/coreos/etcd/blob/master/client) - the officially maintained Go client
- [go-etcd](https://github.com/coreos/go-etcd) - the deprecated official client. May be useful for older (<2.0.0) versions of etcd.
- [go-etcd](https://github.com/coreos/go-etcd) - Supports v2
**Java libraries**
- [boonproject/etcd](https://github.com/boonproject/boon/blob/master/etcd/README.md) - Supports v2, Async/Sync and waits
- [justinsb/jetcd](https://github.com/justinsb/jetcd)
- [diwakergupta/jetcd](https://github.com/diwakergupta/jetcd) - Supports v2
- [jurmous/etcd4j](https://github.com/jurmous/etcd4j) - Supports v2, Async/Sync, waits and SSL
- [AdoHe/etcd4j](http://github.com/AdoHe/etcd4j) - Supports v2 (enhance for real production cluster)
**Python libraries**
- [jplana/python-etcd](https://github.com/jplana/python-etcd) - Supports v2
- [russellhaering/txetcd](https://github.com/russellhaering/txetcd) - a Twisted Python library
- [cholcombe973/autodock](https://github.com/cholcombe973/autodock) - A docker deployment automation tool
- [lisael/aioetcd](https://github.com/lisael/aioetcd) - (Python 3.4+) Asyncio coroutines client (Supports v2)
**Node libraries**
- [stianeikeland/node-etcd](https://github.com/stianeikeland/node-etcd) - Supports v2 (w Coffeescript)
- [lavagetto/nodejs-etcd](https://github.com/lavagetto/nodejs-etcd) - Supports v2
- [deedubs/node-etcd-config](https://github.com/deedubs/node-etcd-config) - Supports v2
**Ruby libraries**
@ -50,11 +35,6 @@
**C libraries**
- [jdarcy/etcd-api](https://github.com/jdarcy/etcd-api) - Supports v2
- [shafreeck/cetcd](https://github.com/shafreeck/cetcd) - Supports v2
**C++ libraries**
- [edwardcapriolo/etcdcpp](https://github.com/edwardcapriolo/etcdcpp) - Supports v2
- [suryanathan/etcdcpp](https://github.com/suryanathan/etcdcpp) - Supports v2 (with waits)
**Clojure libraries**
@ -68,7 +48,6 @@
**.Net Libraries**
- [wangjia184/etcdnet](https://github.com/wangjia184/etcdnet) - Supports v2
- [drusellers/etcetera](https://github.com/drusellers/etcetera)
**PHP Libraries**
@ -79,13 +58,9 @@
- [wereHamster/etcd-hs](https://github.com/wereHamster/etcd-hs)
**R libraries**
A detailed recap of client functionalities can be found in the [clients compatibility matrix][clients-matrix.md].
- [ropensci/etseed](https://github.com/ropensci/etseed)
**Tcl libraries**
- [efrecon/etcd-tcl](https://github.com/efrecon/etcd-tcl) - Supports v2, except wait.
[clients-matrix.md]: https://github.com/coreos/etcd/blob/master/Documentation/clients-matrix.md
**Chef Integration**
@ -114,11 +89,6 @@
- [configdb](https://git.autistici.org/ai/configdb/tree/master) - A REST relational abstraction on top of arbitrary database backends, aimed at storing configs and inventories.
- [scrz](https://github.com/scrz/scrz) - Container manager, stores configuration in etcd.
- [fleet](https://github.com/coreos/fleet) - Distributed init system
- [kubernetes/kubernetes](https://github.com/kubernetes/kubernetes) - Container cluster manager introduced by Google.
- [GoogleCloudPlatform/kubernetes](https://github.com/GoogleCloudPlatform/kubernetes) - Container cluster manager.
- [mailgun/vulcand](https://github.com/mailgun/vulcand) - HTTP proxy that uses etcd as a configuration backend.
- [duedil-ltd/discodns](https://github.com/duedil-ltd/discodns) - Simple DNS nameserver using etcd as a database for names and records.
- [skynetservices/skydns](https://github.com/skynetservices/skydns) - RFC compliant DNS server
- [xordataexchange/crypt](https://github.com/xordataexchange/crypt) - Securely store values in etcd using GPG encryption
- [spf13/viper](https://github.com/spf13/viper) - Go configuration library, reads values from ENV, pflags, files, and etcd with optional encryption
- [lytics/metafora](https://github.com/lytics/metafora) - Go distributed task library
- [ryandoyle/nss-etcd](https://github.com/ryandoyle/nss-etcd) - A GNU libc NSS module for resolving names from etcd.

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# Members API
* [List members](#list-members)
* [Add a member](#add-a-member)
* [Delete a member](#delete-a-member)
* [Change the peer urls of a member](#change-the-peer-urls-of-a-member)
## List members
Return an HTTP 200 OK response code and a representation of all members in the etcd cluster.
### Request
```
GET /v2/members HTTP/1.1
```
### Example
```sh
curl http://10.0.0.10:2379/v2/members
```
```json
{
"members": [
{
"id": "272e204152",
"name": "infra1",
"peerURLs": [
"http://10.0.0.10:2380"
],
"clientURLs": [
"http://10.0.0.10:2379"
]
},
{
"id": "2225373f43",
"name": "infra2",
"peerURLs": [
"http://10.0.0.11:2380"
],
"clientURLs": [
"http://10.0.0.11:2379"
]
},
]
}
```
## Add a member
Returns an HTTP 201 response code and the representation of added member with a newly generated a memberID when successful. Returns a string describing the failure condition when unsuccessful.
If the POST body is malformed an HTTP 400 will be returned. If the member exists in the cluster or existed in the cluster at some point in the past an HTTP 409 will be returned. If any of the given peerURLs exists in the cluster an HTTP 409 will be returned. If the cluster fails to process the request within timeout an HTTP 500 will be returned, though the request may be processed later.
### Request
```
POST /v2/members HTTP/1.1
{"peerURLs": ["http://10.0.0.10:2380"]}
```
### Example
```sh
curl http://10.0.0.10:2379/v2/members -XPOST \
-H "Content-Type: application/json" -d '{"peerURLs":["http://10.0.0.10:2380"]}'
```
```json
{
"id": "3777296169",
"peerURLs": [
"http://10.0.0.10:2380"
]
}
```
## Delete a member
Remove a member from the cluster. The member ID must be a hex-encoded uint64.
Returns 204 with empty content when successful. Returns a string describing the failure condition when unsuccessful.
If the member does not exist in the cluster an HTTP 500(TODO: fix this) will be returned. If the cluster fails to process the request within timeout an HTTP 500 will be returned, though the request may be processed later.
### Request
```
DELETE /v2/members/<id> HTTP/1.1
```
### Example
```sh
curl http://10.0.0.10:2379/v2/members/272e204152 -XDELETE
```
## Change the peer urls of a member
Change the peer urls of a given member. The member ID must be a hex-encoded uint64. Returns 204 with empty content when successful. Returns a string describing the failure condition when unsuccessful.
If the POST body is malformed an HTTP 400 will be returned. If the member does not exist in the cluster an HTTP 404 will be returned. If any of the given peerURLs exists in the cluster an HTTP 409 will be returned. If the cluster fails to process the request within timeout an HTTP 500 will be returned, though the request may be processed later.
### Request
```
PUT /v2/members/<id> HTTP/1.1
{"peerURLs": ["http://10.0.0.10:2380"]}
```
### Example
```sh
curl http://10.0.0.10:2379/v2/members/272e204152 -XPUT \
-H "Content-Type: application/json" -d '{"peerURLs":["http://10.0.0.10:2380"]}'
```

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@ -1,134 +0,0 @@
# Metrics
**NOTE: The metrics feature is considered experimental. We may add/change/remove metrics without warning in future releases.**
etcd uses [Prometheus][prometheus] for metrics reporting in the server. The metrics can be used for real-time monitoring and debugging.
etcd only stores these data in memory. If a member restarts, metrics will reset.
The simplest way to see the available metrics is to cURL the metrics endpoint `/metrics` of etcd. The format is described [here](http://prometheus.io/docs/instrumenting/exposition_formats/).
Follow the [Prometheus getting started doc][prometheus-getting-started] to spin up a Prometheus server to collect etcd metrics.
The naming of metrics follows the suggested [best practice of Prometheus][prometheus-naming]. A metric name has an `etcd` prefix as its namespace and a subsystem prefix (for example `wal` and `etcdserver`).
etcd now exposes the following metrics:
## etcdserver
| Name | Description | Type |
|-----------------------------------------|--------------------------------------------------|-----------|
| file_descriptors_used_total | The total number of file descriptors used | Gauge |
| proposal_durations_seconds | The latency distributions of committing proposal | Histogram |
| pending_proposal_total | The total number of pending proposals | Gauge |
| proposal_failed_total | The total number of failed proposals | Counter |
High file descriptors (`file_descriptors_used_total`) usage (near the file descriptors limitation of the process) indicates a potential out of file descriptors issue. That might cause etcd fails to create new WAL files and panics.
[Proposal][glossary-proposal] durations (`proposal_durations_seconds`) provides a histogram about the proposal commit latency. Latency can be introduced into this process by network and disk IO.
Pending proposal (`pending_proposal_total`) gives you an idea about how many proposal are in the queue and waiting for commit. An increasing pending number indicates a high client load or an unstable cluster.
Failed proposals (`proposal_failed_total`) are normally related to two issues: temporary failures related to a leader election or longer duration downtime caused by a loss of quorum in the cluster.
## wal
| Name | Description | Type |
|------------------------------------|--------------------------------------------------|-----------|
| fsync_durations_seconds | The latency distributions of fsync called by wal | Histogram |
| last_index_saved | The index of the last entry saved by wal | Gauge |
Abnormally high fsync duration (`fsync_durations_seconds`) indicates disk issues and might cause the cluster to be unstable.
## http requests
These metrics describe the serving of requests (non-watch events) served by etcd members in non-proxy mode: total
incoming requests, request failures and processing latency (inc. raft rounds for storage). They are useful for tracking
user-generated traffic hitting the etcd cluster .
All these metrics are prefixed with `etcd_http_`
| Name | Description | Type |
|--------------------------------|-----------------------------------------------------------------------------------------|--------------------|
| received_total | Total number of events after parsing and auth. | Counter(method) |
| failed_total | Total number of failed events.   | Counter(method,error) |
| successful_duration_second | Bucketed handling times of the requests, including raft rounds for writes. | Histogram(method) |
Example Prometheus queries that may be useful from these metrics (across all etcd members):
* `sum(rate(etcd_http_failed_total{job="etcd"}[1m]) by (method) / sum(rate(etcd_http_events_received_total{job="etcd"})[1m]) by (method)`
Shows the fraction of events that failed by HTTP method across all members, across a time window of `1m`.
* `sum(rate(etcd_http_received_total{job="etcd",method="GET})[1m]) by (method)`
`sum(rate(etcd_http_received_total{job="etcd",method~="GET})[1m]) by (method)`
Shows the rate of successful readonly/write queries across all servers, across a time window of `1m`.
* `histogram_quantile(0.9, sum(increase(etcd_http_successful_processing_seconds{job="etcd",method="GET"}[5m]) ) by (le))`
`histogram_quantile(0.9, sum(increase(etcd_http_successful_processing_seconds{job="etcd",method!="GET"}[5m]) ) by (le))`
Show the 0.90-tile latency (in seconds) of read/write (respectively) event handling across all members, with a window of `5m`.
## snapshot
| Name | Description | Type |
|--------------------------------------------|------------------------------------------------------------|-----------|
| snapshot_save_total_durations_seconds | The total latency distributions of save called by snapshot | Histogram |
Abnormally high snapshot duration (`snapshot_save_total_durations_seconds`) indicates disk issues and might cause the cluster to be unstable.
## rafthttp
| Name | Description | Type | Labels |
|-----------------------------------|--------------------------------------------|--------------|--------------------------------|
| message_sent_latency_seconds | The latency distributions of messages sent | HistogramVec | sendingType, msgType, remoteID |
| message_sent_failed_total | The total number of failed messages sent | Summary | sendingType, msgType, remoteID |
Abnormally high message duration (`message_sent_latency_seconds`) indicates network issues and might cause the cluster to be unstable.
An increase in message failures (`message_sent_failed_total`) indicates more severe network issues and might cause the cluster to be unstable.
Label `sendingType` is the connection type to send messages. `message`, `msgapp` and `msgappv2` use HTTP streaming, while `pipeline` does HTTP request for each message.
Label `msgType` is the type of raft message. `MsgApp` is log replication message; `MsgSnap` is snapshot install message; `MsgProp` is proposal forward message; the others are used to maintain raft internal status. If you have a large snapshot, you would expect a long msgSnap sending latency. For other types of messages, you would expect low latency, which is comparable to your ping latency if you have enough network bandwidth.
Label `remoteID` is the member ID of the message destination.
## proxy
etcd members operating in proxy mode do not do store operations. They forward all requests
to cluster instances.
Tracking the rate of requests coming from a proxy allows one to pin down which machine is performing most reads/writes.
All these metrics are prefixed with `etcd_proxy_`
| Name | Description | Type |
|---------------------------|-----------------------------------------------------------------------------------------|--------------------|
| requests_total | Total number of requests by this proxy instance. . | Counter(method) |
| handled_total | Total number of fully handled requests, with responses from etcd members. | Counter(method) |
| dropped_total | Total number of dropped requests due to forwarding errors to etcd members.  | Counter(method,error) |
| handling_duration_seconds | Bucketed handling times by HTTP method, including round trip to member instances. | Histogram(method) |
Example Prometheus queries that may be useful from these metrics (across all etcd servers):
* `sum(rate(etcd_proxy_handled_total{job="etcd"}[1m])) by (method)`
Rate of requests (by HTTP method) handled by all proxies, across a window of `1m`.
* `histogram_quantile(0.9, sum(increase(etcd_proxy_events_handling_time_seconds_bucket{job="etcd",method="GET"}[5m])) by (le))`
`histogram_quantile(0.9, sum(increase(etcd_proxy_events_handling_time_seconds_bucket{job="etcd",method!="GET"}[5m])) by (le))`
Show the 0.90-tile latency (in seconds) of handling of user requests across all proxy machines, with a window of `5m`.
* `sum(rate(etcd_proxy_dropped_total{job="etcd"}[1m])) by (proxying_error)`
Number of failed request on the proxy. This should be 0, spikes here indicate connectivity issues to etcd cluster.
[glossary-proposal]: glossary.md#proposal
[prometheus]: http://prometheus.io/
[prometheus-getting-started](http://prometheus.io/docs/introduction/getting_started/)
[prometheus-naming]: http://prometheus.io/docs/practices/naming/

118
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## Modules
etcd has a number of modules that are built on top of the core etcd API.
These modules provide things like dashboards, locks and leader election (removed).
**Warning**: Modules are deprecated from v0.4 until we have a solid base we can apply them back onto.
For now, we are choosing to focus on raft algorithm and core etcd to make sure that it works correctly and fast.
And it is time consuming to maintain these modules in this period, given that etcd's API changes from time to time.
Moreover, the lock module has some unfixed bugs, which may mislead users.
But we also notice that these modules are popular and useful, and plan to add them back with full functionality as soon as possible.
### Dashboard
An HTML dashboard can be found at `http://127.0.0.1:4001/mod/dashboard/`.
This dashboard is compiled into the etcd binary and uses the same API as regular etcd clients.
Use the `-cors='*'` flag to allow your browser to request information from the current master as it changes.
### Lock
The Lock module implements a fair lock that can be used when lots of clients want access to a single resource.
A lock can be associated with a value.
The value is unique so if a lock tries to request a value that is already queued for a lock then it will find it and watch until that value obtains the lock.
You may supply a `timeout` which will cancel the lock request if it is not obtained within `timeout` seconds. If `timeout` is not supplied, it is presumed to be infinite. If `timeout` is `0`, the lock request will fail if it is not immediately acquired.
If you lock the same value on a key from two separate curl sessions they'll both return at the same time.
Here's the API:
**Acquire a lock (with no value) for "customer1"**
```sh
curl -X POST http://127.0.0.1:4001/mod/v2/lock/customer1?ttl=60
```
**Acquire a lock for "customer1" that is associated with the value "bar"**
```sh
curl -X POST http://127.0.0.1:4001/mod/v2/lock/customer1?ttl=60 -d value=bar
```
**Acquire a lock for "customer1" that is associated with the value "bar" only if it is done within 2 seconds**
```sh
curl -X POST http://127.0.0.1:4001/mod/v2/lock/customer1?ttl=60 -d value=bar -d timeout=2
```
**Renew the TTL on the "customer1" lock for index 2**
```sh
curl -X PUT http://127.0.0.1:4001/mod/v2/lock/customer1?ttl=60 -d index=2
```
**Renew the TTL on the "customer1" lock for value "bar"**
```sh
curl -X PUT http://127.0.0.1:4001/mod/v2/lock/customer1?ttl=60 -d value=bar
```
**Retrieve the current value for the "customer1" lock.**
```sh
curl http://127.0.0.1:4001/mod/v2/lock/customer1
```
**Retrieve the current index for the "customer1" lock**
```sh
curl http://127.0.0.1:4001/mod/v2/lock/customer1?field=index
```
**Delete the "customer1" lock with the index 2**
```sh
curl -X DELETE http://127.0.0.1:4001/mod/v2/lock/customer1?index=2
```
**Delete the "customer1" lock with the value "bar"**
```sh
curl -X DELETE http://127.0.0.1:4001/mod/v2/lock/customer1?value=bar
```
### Leader Election (Deprecated and Removed in 0.4)
The Leader Election module wraps the Lock module to allow clients to come to consensus on a single value.
This is useful when you want one server to process at a time but allow other servers to fail over.
The API is similar to the Lock module but is limited to simple strings values.
Here's the API:
**Attempt to set a value for the "order_processing" leader key:**
```sh
curl -X PUT http://127.0.0.1:4001/mod/v2/leader/order_processing?ttl=60 -d name=myserver1.foo.com
```
**Retrieve the current value for the "order_processing" leader key:**
```sh
curl http://127.0.0.1:4001/mod/v2/leader/order_processing
myserver1.foo.com
```
**Remove a value from the "order_processing" leader key:**
```sh
curl -X DELETE http://127.0.0.1:4001/mod/v2/leader/order_processing?name=myserver1.foo.com
```
If multiple clients attempt to set the value for a key then only one will succeed.
The other clients will hang until the current value is removed because of TTL or because of a `DELETE` operation.
Multiple clients can submit the same value and will all be notified when that value succeeds.
To update the TTL of a value simply reissue the same `PUT` command that you used to set the value.

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# Optimal etcd Cluster Size
etcd's Raft consensus algorithm is most efficient in small clusters between 3 and 9 peers. For clusters larger than 9, etcd will select a subset of instances to participate in the algorithm in order to keep it efficient. The end of this document briefly explores how etcd works internally and why these choices have been made.
## Cluster Management
You can manage the active cluster size through the [cluster config API](https://github.com/coreos/etcd/blob/master/Documentation/api.md#cluster-config). `activeSize` represents the etcd peers allowed to actively participate in the consensus algorithm.
If the total number of etcd instances exceeds this number, additional peers are started as [standbys](https://github.com/coreos/etcd/blob/master/Documentation/design/standbys.md), which can be promoted to active participation if one of the existing active instances has failed or been removed.
## Internals of etcd
### Writing to etcd
Writes to an etcd peer are always redirected to the leader of the cluster and distributed to all of the peers immediately. A write is only considered successful when a majority of the peers acknowledge the write.
For example, in a cluster with 5 peers, a write operation is only as fast as the 3rd fastest machine. This is the main reason for keeping the number of active peers below 9. In practice, you only need to worry about write performance in high latency environments such as a cluster spanning multiple data centers.
### Leader Election
The leader election process is similar to writing a key &mdash; a majority of the active peers must acknowledge the new leader before cluster operations can continue. The longer each peer takes to elect a new leader means you have to wait longer before you can write to the cluster again. In low latency environments this process takes milliseconds.
### Odd Active Cluster Size
The other important cluster optimization is to always have an odd active cluster size (i.e. `activeSize`). Adding an odd node to the number of peers doesn't change the size of the majority and therefore doesn't increase the total latency of the majority as described above. But, you gain a higher tolerance for peer failure by adding the extra machine. You can see this in practice when comparing two even and odd sized clusters:
| Active Peers | Majority | Failure Tolerance |
|--------------|------------|-------------------|
| 1 peers | 1 peers | None |
| 3 peers | 2 peers | 1 peer |
| 4 peers | 3 peers | 1 peer |
| 5 peers | 3 peers | **2 peers** |
| 6 peers | 4 peers | 2 peers |
| 7 peers | 4 peers | **3 peers** |
| 8 peers | 5 peers | 3 peers |
| 9 peers | 5 peers | **4 peers** |
As you can see, adding another peer to bring the number of active peers up to an odd size is always worth it. During a network partition, an odd number of active peers also guarantees that there will almost always be a majority of the cluster that can continue to operate and be the source of truth when the partition ends.

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@ -1,28 +0,0 @@
# Miscellaneous APIs
* [Getting the etcd version](#getting-the-etcd-version)
* [Checking health of an etcd member node](#checking-health-of-an-etcd-member-node)
## Getting the etcd version
The etcd version of a specific instance can be obtained from the `/version` endpoint.
```sh
curl -L http://127.0.0.1:2379/version
```
```
etcd 2.0.12
```
## Checking health of an etcd member node
etcd provides a `/health` endpoint to verify the health of a particular member.
```sh
curl http://10.0.0.10:2379/health
```
```json
{"health": "true"}
```

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@ -15,7 +15,7 @@ when asked
2. Update your repository data with `pkg update`
3. Install etcd with `pkg install coreos-etcd coreos-etcdctl`
3. Install etcd with `pkg install coreos­etcd coreos­etcdctl`
4. Verify successful installation with `pkg info | grep etcd` and you should get:

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@ -0,0 +1,7 @@
etcd is being used successfully by many companies in production. It is,
however, under active development and systems like etcd are difficult to get
correct. If you are comfortable with bleeding-edge software please use etcd and
provide us with the feedback and testing young software needs.
When the etcd team feels confident removing this warning we will release etcd
1.0.

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# Production Users
This document tracks people and use cases for etcd in production. By creating a list of production use cases we hope to build a community of advisors that we can reach out to with experience using various etcd applications, operation environments, and cluster sizes. The etcd development team may reach out periodically to check-in on your experience and update this list.
## discovery.etcd.io
- *Application*: https://github.com/coreos/discovery.etcd.io
- *Launched*: Feb. 2014
- *Cluster Size*: 5 members, 5 discovery proxies
- *Order of Data Size*: 100s of Megabytes
- *Operator*: CoreOS, brandon.philips@coreos.com
- *Environment*: AWS
- *Backups*: Periodic async to S3
discovery.etcd.io is the longest continuously running etcd backed service that we know about. It is the basis of automatic cluster bootstrap and was launched in Feb. 2014: https://coreos.com/blog/etcd-0.3.0-released/.
## OpenTable
- *Application*: OpenTable internal service discovery and cluster configuration management
- *Launched*: May 2014
- *Cluster Size*: 3 members each in 6 independent clusters; approximately 50 nodes reading / writing
- *Order of Data Size*: 10s of MB
- *Operator*: OpenTable, Inc; sschlansker@opentable.com
- *Environment*: AWS, VMWare
- *Backups*: None, all data can be re-created if necessary.
## cycoresys.com
- *Application*: multiple
- *Launched*: Jul. 2014
- *Cluster Size*: 3 members, _n_ proxies
- *Order of Data Size*: 100s of kilobytes
- *Operator*: CyCore Systems, Inc, sys@cycoresys.com
- *Environment*: Baremetal
- *Backups*: Periodic sync to Ceph RadosGW and DigitalOcean VM
CyCore Systems provides architecture and engineering for computing systems. This cluster provides microservices, virtual machines, databases, storage clusters to a number of clients. It is built on CoreOS machines, with each machine in the cluster running etcd as a peer or proxy.
## Radius Intelligence
- *Application*: multiple internal tools, Kubernetes clusters, bootstrappable system configs
- *Launched*: June 2015
- *Cluster Size*: 2 clusters of 5 and 3 members; approximately a dozen nodes read/write
- *Order of Data Size*: 100s of kilobytes
- *Operator*: Radius Intelligence; jcderr@radius.com
- *Environment*: AWS, CoreOS, Kubernetes
- *Backups*: None, all data can be recreated if necessary.
Radius Intelligence uses Kubernetes running CoreOS to containerize and scale internal toolsets. Examples include running [JetBrains TeamCity][teamcity] and internal AWS security and cost reporting tools. etcd clusters back these clusters as well as provide some basic environment bootstrapping configuration keys.
[teamcity]: https://www.jetbrains.com/teamcity/

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# Proxy
etcd can run as a transparent proxy. Doing so allows for easy discovery of etcd within your infrastructure, since it can run on each machine as a local service. In this mode, etcd acts as a reverse proxy and forwards client requests to an active etcd cluster. The etcd proxy does not participate in the consensus replication of the etcd cluster, thus it neither increases the resilience nor decreases the write performance of the etcd cluster.
etcd currently supports two proxy modes: `readwrite` and `readonly`. The default mode is `readwrite`, which forwards both read and write requests to the etcd cluster. A `readonly` etcd proxy only forwards read requests to the etcd cluster, and returns `HTTP 501` to all write requests.
The proxy will shuffle the list of cluster members periodically to avoid sending all connections to a single member.
The member list used by an etcd proxy consists of all client URLs advertised in the cluster. These client URLs are specified in each etcd cluster member's `advertise-client-urls` option.
An etcd proxy examines several command-line options to discover its peer URLs. In order of precedence, these options are `discovery`, `discovery-srv`, and `initial-cluster`. The `initial-cluster` option is set to a comma-separated list of one or more etcd peer URLs used temporarily in order to discover the permanent cluster.
After establishing a list of peer URLs in this manner, the proxy retrieves the list of client URLs from the first reachable peer. These client URLs are specified by the `advertise-client-urls` option to etcd peers. The proxy then continues to connect to the first reachable etcd cluster member every thirty seconds to refresh the list of client URLs.
While etcd proxies therefore do not need to be given the `advertise-client-urls` option, as they retrieve this configuration from the cluster, this implies that `initial-cluster` must be set correctly for every proxy, and the `advertise-client-urls` option must be set correctly for every non-proxy, first-order cluster peer. Otherwise, requests to any etcd proxy would be forwarded improperly. Take special care not to set the `advertise-client-urls` option to URLs that point to the proxy itself, as such a configuration will cause the proxy to enter a loop, forwarding requests to itself until resources are exhausted. To correct either case, stop etcd and restart it with the correct URLs.
[This example Procfile][procfile] illustrates the difference in the etcd peer and proxy command lines used to configure and start a cluster with one proxy under the [goreman process management utility][goreman].
To summarize etcd proxy startup and peer discovery:
1. etcd proxies execute the following steps in order until the cluster *peer-urls* are known:
1. If `discovery` is set for the proxy, ask the given discovery service for
the *peer-urls*. The *peer-urls* will be the combined
`initial-advertise-peer-urls` of all first-order, non-proxy cluster
members.
2. If `discovery-srv` is set for the proxy, the *peer-urls* are discovered
from DNS.
3. If `initial-cluster` is set for the proxy, that will become the value of
*peer-urls*.
4. Otherwise use the default value of
`http://localhost:2380,http://localhost:7001`.
2. These *peer-urls* are used to contact the (non-proxy) members of the cluster
to find their *client-urls*. The *client-urls* will thus be the combined
`advertise-client-urls` of all cluster members (i.e. non-proxies).
3. Request of clients of the proxy will be forwarded (proxied) to these
*client-urls*.
Always start the first-order etcd cluster members first, then any proxies. A proxy must be able to reach the cluster members to retrieve its configuration, and will attempt connections somewhat aggressively in the absence of such a channel. Starting the members before any proxy ensures the proxy can discover the client URLs when it later starts.
## Using an etcd proxy
To start etcd in proxy mode, you need to provide three flags: `proxy`, `listen-client-urls`, and `initial-cluster` (or `discovery`).
To start a readwrite proxy, set `-proxy on`; To start a readonly proxy, set `-proxy readonly`.
The proxy will be listening on `listen-client-urls` and forward requests to the etcd cluster discovered from in `initial-cluster` or `discovery` url.
### Start an etcd proxy with a static configuration
To start a proxy that will connect to a statically defined etcd cluster, specify the `initial-cluster` flag:
```
etcd --proxy on \
--listen-client-urls http://127.0.0.1:8080 \
--initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380
```
### Start an etcd proxy with the discovery service
If you bootstrap an etcd cluster using the [discovery service][discovery-service], you can also start the proxy with the same `discovery`.
To start a proxy using the discovery service, specify the `discovery` flag. The proxy will wait until the etcd cluster defined at the `discovery` url finishes bootstrapping, and then start to forward the requests.
```
etcd --proxy on \
--listen-client-urls http://127.0.0.1:8080 \
--discovery https://discovery.etcd.io/3e86b59982e49066c5d813af1c2e2579cbf573de \
```
## Fallback to proxy mode with discovery service
If you bootstrap an etcd cluster using [discovery service][discovery-service] with more than the expected number of etcd members, the extra etcd processes will fall back to being `readwrite` proxies by default. They will forward the requests to the cluster as described above. For example, if you create a discovery url with `size=5`, and start ten etcd processes using that same discovery url, the result will be a cluster with five etcd members and five proxies. Note that this behaviour can be disabled with the `discovery-fallback='exit'` flag.
## Promote a proxy to a member of etcd cluster
A Proxy is in the part of etcd cluster that does not participate in consensus. A proxy will not promote itself to an etcd member that participates in consensus automatically in any case.
If you want to promote a proxy to an etcd member, there are four steps you need to follow:
- use etcdctl to add the proxy node as an etcd member into the existing cluster
- stop the etcd proxy process or service
- remove the existing proxy data directory
- restart the etcd process with new member configuration
## Example
We assume you have a one member etcd cluster with one proxy. The cluster information is listed below:
|Name|Address|
|------|---------|
|infra0|10.0.1.10|
|proxy0|10.0.1.11|
This example walks you through a case that you promote one proxy to an etcd member. The cluster will become a two member cluster after finishing the four steps.
### Add a new member into the existing cluster
First, use etcdctl to add the member to the cluster, which will output the environment variables need to correctly configure the new member:
``` bash
$ etcdctl -endpoint http://10.0.1.10:2379 member add infra1 http://10.0.1.11:2380
added member 9bf1b35fc7761a23 to cluster
ETCD_NAME="infra1"
ETCD_INITIAL_CLUSTER="infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380"
ETCD_INITIAL_CLUSTER_STATE=existing
```
### Stop the proxy process
Stop the existing proxy so we can wipe it's state on disk and reload it with the new configuration:
``` bash
px aux | grep etcd
kill %etcd_proxy_pid%
```
or (if you are running etcd proxy as etcd service under systemd)
``` bash
sudo systemctl stop etcd
```
### Remove the existing proxy data dir
``` bash
rm -rf %data_dir%/proxy
```
### Start etcd as a new member
Finally, start the reconfigured member and make sure it joins the cluster correctly:
``` bash
$ export ETCD_NAME="infra1"
$ export ETCD_INITIAL_CLUSTER="infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380"
$ export ETCD_INITIAL_CLUSTER_STATE=existing
$ etcd --listen-client-urls http://10.0.1.11:2379 \
--advertise-client-urls http://10.0.1.11:2379 \
--listen-peer-urls http://10.0.1.11:2380 \
--initial-advertise-peer-urls http://10.0.1.11:2380 \
--data-dir %data_dir%
```
If you are running etcd under systemd, you should modify the service file with correct configuration and restart the service:
``` bash
sudo systemd restart etcd
```
If an error occurs, check the [add member troubleshooting doc][runtime-configuration].
[discovery-service]: clustering.md#discovery
[goreman]: https://github.com/mattn/goreman
[procfile]: /Procfile
[runtime-configuration]: runtime-configuration.md#error-cases-when-adding-members

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# Reporting Bugs
If you find bugs or documentation mistakes in the etcd project, please let us know by [opening an issue][issue]. We treat bugs and mistakes very seriously and believe no issue is too small. Before creating a bug report, please check that an issue reporting the same problem does not already exist.
To make your bug report accurate and easy to understand, please try to create bug reports that are:
- Specific. Include as much details as possible: which version, what environment, what configuration, etc. You can also attach etcd log (the starting log with etcd configuration is especially important).
- Reproducible. Include the steps to reproduce the problem. We understand some issues might be hard to reproduce, please includes the steps that might lead to the problem. You can also attach the affected etcd data dir and stack strace to the bug report.
- Isolated. Please try to isolate and reproduce the bug with minimum dependencies. It would significantly slow down the speed to fix a bug if too many dependencies are involved in a bug report. Debugging external systems that rely on etcd is out of scope, but we are happy to point you in the right direction or help you interact with etcd in the correct manner.
- Unique. Do not duplicate existing bug report.
- Scoped. One bug per report. Do not follow up with another bug inside one report.
You might also want to read [Elika Etemads article on filing good bug reports][filing-good-bugs] before creating a bug report.
We might ask you for further information to locate a bug. A duplicated bug report will be closed.
## Frequently Asked Questions
### How to get a stack trace
``` bash
$ kill -QUIT $PID
```
### How to get etcd version
``` bash
$ etcd --version
```
### How to get etcd configuration and log when it runs as systemd service etcd2.service
``` bash
$ sudo systemctl cat etcd2
$ sudo journalctl -u etcd2
```
Due to an upstream systemd bug, journald may miss the last few log lines when its process exit. If journalctl tells you that etcd stops without fatal or panic message, you could try `sudo journalctl -f -t etcd2` to get full log.
[etcd-issue]: https://github.com/coreos/etcd/issues/new
[filing-good-bugs]: http://fantasai.inkedblade.net/style/talks/filing-good-bugs/

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# Overview
The etcd v3 API is designed to give users a more efficient and cleaner abstraction compared to etcd v2. There are a number of semantic and protocol changes in this new API. For an overview [see Xiang Li's video](https://youtu.be/J5AioGtEPeQ?t=211).
To prove out the design of the v3 API the team has also built [a number of example recipes](https://github.com/coreos/etcd/tree/master/contrib/recipes), there is a [video discussing these recipes too](https://www.youtube.com/watch?v=fj-2RY-3yVU&feature=youtu.be&t=590).
# Design
1. Flatten binary key-value space
2. Keep the event history until compaction
- access to old version of keys
- user controlled history compaction
3. Support range query
- Pagination support with limit argument
- Support consistency guarantee across multiple range queries
4. Replace TTL key with Lease
- more efficient/ low cost keep alive
- a logical group of TTL keys
5. Replace CAS/CAD with multi-object Txn
- MUCH MORE powerful and flexible
6. Support efficient watching with multiple ranges
7. RPC API supports the completed set of APIs.
- more efficient than JSON/HTTP
- additional txn/lease support
8. HTTP API supports a subset of APIs.
- easy for people to try out etcd
- easy for people to write simple etcd application
## Notes
### Request Size Limitation
The max request size is around 1MB. Since etcd replicates requests in a streaming fashion, a very large
request might block other requests for a long time. The use case for etcd is to store small configuration
values, so we prevent user from submitting large requests. This also applies to Txn requests. We might loosen
the size in the future a little bit or make it configurable.
## Protobuf Defined API
[api protobuf][api-protobuf]
[kv protobuf][kv-protobuf]
## Examples
### Put a key (foo=bar)
```
// A put is always successful
Put( PutRequest { key = foo, value = bar } )
PutResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 1,
raft_term = 0x1,
}
```
### Get a key (assume we have foo=bar)
```
Get ( RangeRequest { key = foo } )
RangeResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 1,
raft_term = 0x1,
kvs = {
{
key = foo,
value = bar,
create_revision = 1,
mod_revision = 1,
version = 1;
},
},
}
```
### Range over a key space (assume we have foo0=bar0… foo100=bar100)
```
Range ( RangeRequest { key = foo, end_key = foo80, limit = 30 } )
RangeResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 100,
raft_term = 0x1,
kvs = {
{
key = foo0,
value = bar0,
create_revision = 1,
mod_revision = 1,
version = 1;
},
...,
{
key = foo30,
value = bar30,
create_revision = 30,
mod_revision = 30,
version = 1;
},
},
}
```
### Finish a txn (assume we have foo0=bar0, foo1=bar1)
```
Txn(TxnRequest {
// mod_revision of foo0 is equal to 1, mod_revision of foo1 is greater than 1
compare = {
{compareType = equal, key = foo0, mod_revision = 1},
{compareType = greater, key = foo1, mod_revision = 1}}
},
// if the comparison succeeds, put foo2 = bar2
success = {PutRequest { key = foo2, value = success }},
// if the comparison fails, put foo2=fail
failure = {PutRequest { key = foo2, value = failure }},
)
TxnResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 3,
raft_term = 0x1,
succeeded = true,
responses = {
// response of PUT foo2=success
{
cluster_id = 0x1000,
member_id = 0x1,
revision = 3,
raft_term = 0x1,
}
}
}
```
### Watch on a key/range
```
Watch( WatchRequest{
key = foo,
end_key = fop, // prefix foo
start_revision = 20,
end_revision = 10000,
// server decided notification frequency
progress_notification = true,
}
… // this can be a watch request stream
)
// put (foo0=bar0) event at 3
WatchResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 3,
raft_term = 0x1,
event_type = put,
kv = {
key = foo0,
value = bar0,
create_revision = 1,
mod_revision = 1,
version = 1;
},
}
// a notification at 2000
WatchResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 2000,
raft_term = 0x1,
// nil event as notification
}
// put (foo0=bar3000) event at 3000
WatchResponse {
cluster_id = 0x1000,
member_id = 0x1,
revision = 3000,
raft_term = 0x1,
event_type = put,
kv = {
key = foo0,
value = bar3000,
create_revision = 1,
mod_revision = 3000,
version = 2;
},
}
```
[api-protobuf]: https://github.com/coreos/etcd/blob/master/etcdserver/etcdserverpb/rpc.proto
[kv-protobuf]: https://github.com/coreos/etcd/blob/master/storage/storagepb/kv.proto

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@ -1,184 +0,0 @@
# Runtime Reconfiguration
etcd comes with support for incremental runtime reconfiguration, which allows users to update the membership of the cluster at run time.
Reconfiguration requests can only be processed when the majority of the cluster members are functioning. It is **highly recommended** to always have a cluster size greater than two in production. It is unsafe to remove a member from a two member cluster. The majority of a two member cluster is also two. If there is a failure during the removal process, the cluster might not able to make progress and need to [restart from majority failure][majority failure].
To better understand the design behind runtime reconfiguration, we suggest you read [the runtime reconfiguration document][runtime-reconf].
## Reconfiguration Use Cases
Let's walk through some common reasons for reconfiguring a cluster. Most of these just involve combinations of adding or removing a member, which are explained below under [Cluster Reconfiguration Operations][cluster-reconf].
### Cycle or Upgrade Multiple Machines
If you need to move multiple members of your cluster due to planned maintenance (hardware upgrades, network downtime, etc.), it is recommended to modify members one at a time.
It is safe to remove the leader, however there is a brief period of downtime while the election process takes place. If your cluster holds more than 50MB, it is recommended to [migrate the member's data directory][member migration].
### Change the Cluster Size
Increasing the cluster size can enhance [failure tolerance][fault tolerance table] and provide better read performance. Since clients can read from any member, increasing the number of members increases the overall read throughput.
Decreasing the cluster size can improve the write performance of a cluster, with a trade-off of decreased resilience. Writes into the cluster are replicated to a majority of members of the cluster before considered committed. Decreasing the cluster size lowers the majority, and each write is committed more quickly.
### Replace A Failed Machine
If a machine fails due to hardware failure, data directory corruption, or some other fatal situation, it should be replaced as soon as possible. Machines that have failed but haven't been removed adversely affect your quorum and reduce the tolerance for an additional failure.
To replace the machine, follow the instructions for [removing the member][remove member] from the cluster, and then [add a new member][add member] in its place. If your cluster holds more than 50MB, it is recommended to [migrate the failed member's data directory][member migration] if you can still access it.
### Restart Cluster from Majority Failure
If the majority of your cluster is lost or all of your nodes have changed IP addresses, then you need to take manual action in order to recover safely.
The basic steps in the recovery process include [creating a new cluster using the old data][disaster recovery], forcing a single member to act as the leader, and finally using runtime configuration to [add new members][add member] to this new cluster one at a time.
## Cluster Reconfiguration Operations
Now that we have the use cases in mind, let us lay out the operations involved in each.
Before making any change, the simple majority (quorum) of etcd members must be available.
This is essentially the same requirement as for any other write to etcd.
All changes to the cluster are done one at a time:
* To update a single member peerURLs you will make an update operation
* To replace a single member you will make an add then a remove operation
* To increase from 3 to 5 members you will make two add operations
* To decrease from 5 to 3 you will make two remove operations
All of these examples will use the `etcdctl` command line tool that ships with etcd.
If you want to use the members API directly you can find the documentation [here][member-api].
### Update a Member
#### Update advertise client URLs
If you would like to update the advertise client URLs of a member, you can simply restart
that member with updated client urls flag (`--advertise-client-urls`) or environment variable
(`ETCD_ADVERTISE_CLIENT_URLS`). The restarted member will self publish the updated URLs.
A wrongly updated client URL will not affect the health of the etcd cluster.
#### Update advertise peer URLs
If you would like to update the advertise peer URLs of a member, you have to first update
it explicitly via member command and then restart the member. The additional action is required
since updating peer URLs changes the cluster wide configuration and can affect the health of the etcd cluster.
To update the peer URLs, first, we need to find the target member's ID. You can list all members with `etcdctl`:
```sh
$ etcdctl member list
6e3bd23ae5f1eae0: name=node2 peerURLs=http://localhost:23802 clientURLs=http://127.0.0.1:23792
924e2e83e93f2560: name=node3 peerURLs=http://localhost:23803 clientURLs=http://127.0.0.1:23793
a8266ecf031671f3: name=node1 peerURLs=http://localhost:23801 clientURLs=http://127.0.0.1:23791
```
In this example let's `update` a8266ecf031671f3 member ID and change its peerURLs value to http://10.0.1.10:2380
```sh
$ etcdctl member update a8266ecf031671f3 http://10.0.1.10:2380
Updated member with ID a8266ecf031671f3 in cluster
```
### Remove a Member
Let us say the member ID we want to remove is a8266ecf031671f3.
We then use the `remove` command to perform the removal:
```sh
$ etcdctl member remove a8266ecf031671f3
Removed member a8266ecf031671f3 from cluster
```
The target member will stop itself at this point and print out the removal in the log:
```
etcd: this member has been permanently removed from the cluster. Exiting.
```
It is safe to remove the leader, however the cluster will be inactive while a new leader is elected. This duration is normally the period of election timeout plus the voting process.
### Add a New Member
Adding a member is a two step process:
* Add the new member to the cluster via the [members API][member-api] or the `etcdctl member add` command.
* Start the new member with the new cluster configuration, including a list of the updated members (existing members + the new member).
Using `etcdctl` let's add the new member to the cluster by specifying its [name][conf-name] and [advertised peer URLs][conf-adv-peer]:
```sh
$ etcdctl member add infra3 http://10.0.1.13:2380
added member 9bf1b35fc7761a23 to cluster
ETCD_NAME="infra3"
ETCD_INITIAL_CLUSTER="infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380,infra3=http://10.0.1.13:2380"
ETCD_INITIAL_CLUSTER_STATE=existing
```
`etcdctl` has informed the cluster about the new member and printed out the environment variables needed to successfully start it.
Now start the new etcd process with the relevant flags for the new member:
```sh
$ export ETCD_NAME="infra3"
$ export ETCD_INITIAL_CLUSTER="infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380,infra3=http://10.0.1.13:2380"
$ export ETCD_INITIAL_CLUSTER_STATE=existing
$ etcd -listen-client-urls http://10.0.1.13:2379 -advertise-client-urls http://10.0.1.13:2379 -listen-peer-urls http://10.0.1.13:2380 -initial-advertise-peer-urls http://10.0.1.13:2380 -data-dir %data_dir%
```
The new member will run as a part of the cluster and immediately begin catching up with the rest of the cluster.
If you are adding multiple members the best practice is to configure a single member at a time and verify it starts correctly before adding more new members.
If you add a new member to a 1-node cluster, the cluster cannot make progress before the new member starts because it needs two members as majority to agree on the consensus. You will only see this behavior between the time `etcdctl member add` informs the cluster about the new member and the new member successfully establishing a connection to the existing one.
#### Error Cases When Adding Members
In the following case we have not included our new host in the list of enumerated nodes.
If this is a new cluster, the node must be added to the list of initial cluster members.
```sh
$ etcd -name infra3 \
-initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380 \
-initial-cluster-state existing
etcdserver: assign ids error: the member count is unequal
exit 1
```
In this case we give a different address (10.0.1.14:2380) to the one that we used to join the cluster (10.0.1.13:2380).
```sh
$ etcd -name infra4 \
-initial-cluster infra0=http://10.0.1.10:2380,infra1=http://10.0.1.11:2380,infra2=http://10.0.1.12:2380,infra4=http://10.0.1.14:2380 \
-initial-cluster-state existing
etcdserver: assign ids error: unmatched member while checking PeerURLs
exit 1
```
When we start etcd using the data directory of a removed member, etcd will exit automatically if it connects to any active member in the cluster:
```sh
$ etcd
etcd: this member has been permanently removed from the cluster. Exiting.
exit 1
```
### Strict Reconfiguration Check Mode (`-strict-reconfig-check`)
As described in the above, the best practice of adding new members is to configure a single member at a time and verify it starts correctly before adding more new members. This step by step approach is very important because if newly added members is not configured correctly (for example the peer URLs are incorrect), the cluster can lose quorum. The quorum loss happens since the newly added member are counted in the quorum even if that member is not reachable from other existing members. Also quorum loss might happen if there is a connectivity issue or there are operational issues.
For avoiding this problem, etcd provides an option `-strict-reconfig-check`. If this option is passed to etcd, etcd rejects reconfiguration requests if the number of started members will be less than a quorum of the reconfigured cluster.
It is recommended to enable this option. However, it is disabled by default because of keeping compatibility.
[add member]: #add-a-new-member
[cluster-reconf]: #cluster-reconfiguration-operations
[conf-adv-peer]: configuration.md#-initial-advertise-peer-urls
[conf-name]: configuration.md#-name
[disaster recovery]: admin_guide.md#disaster-recovery
[fault tolerance table]: admin_guide.md#fault-tolerance-table
[majority failure]: #restart-cluster-from-majority-failure
[member-api]: members_api.md
[member migration]: admin_guide.md#member-migration
[remove member]: #remove-a-member
[runtime-reconf]: runtime-reconf-design.md

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@ -1,50 +0,0 @@
# Design of Runtime Reconfiguration
Runtime reconfiguration is one of the hardest and most error prone features in a distributed system, especially in a consensus based system like etcd.
Read on to learn about the design of etcd's runtime reconfiguration commands and how we tackled these problems.
## Two Phase Config Changes Keep you Safe
In etcd, every runtime reconfiguration has to go through [two phases][add-member] for safety reasons. For example, to add a member you need to first inform cluster of new configuration and then start the new member.
Phase 1 - Inform cluster of new configuration
To add a member into etcd cluster, you need to make an API call to request a new member to be added to the cluster. And this is only way that you can add a new member into an existing cluster. The API call returns when the cluster agrees on the configuration change.
Phase 2 - Start new member
To join the etcd member into the existing cluster, you need to specify the correct `initial-cluster` and set `initial-cluster-state` to `existing`. When the member starts, it will contact the existing cluster first and verify the current cluster configuration matches the expected one specified in `initial-cluster`. When the new member successfully starts, you know your cluster reached the expected configuration.
By splitting the process into two discrete phases users are forced to be explicit regarding cluster membership changes. This actually gives users more flexibility and makes things easier to reason about. For example, if there is an attempt to add a new member with the same ID as an existing member in an etcd cluster, the action will fail immediately during phase one without impacting the running cluster. Similar protection is provided to prevent adding new members by mistake. If a new etcd member attempts to join the cluster before the cluster has accepted the configuration change,, it will not be accepted by the cluster.
Without the explicit workflow around cluster membership etcd would be vulnerable to unexpected cluster membership changes. For example, if etcd is running under an init system such as systemd, etcd would be restarted after being removed via the membership API, and attempt to rejoin the cluster on startup. This cycle would continue every time a member is removed via the API and systemd is set to restart etcd after failing, which is unexpected.
We think runtime reconfiguration should be a low frequent operation. We made the decision to keep it explicit and user-driven to ensure configuration safety and keep your cluster always running smoothly under your control.
## Permanent Loss of Quorum Requires New Cluster
If a cluster permanently loses a majority of its members, a new cluster will need to be started from an old data directory to recover the previous state.
It is entirely possible to force removing the failed members from the existing cluster to recover. However, we decided not to support this method since it bypasses the normal consensus committing phase, which is unsafe. If the member to remove is not actually dead or you force to remove different members through different members in the same cluster, you will end up with diverged cluster with same clusterID. This is very dangerous and hard to debug/fix afterwards.
If you have a correct deployment, the possibility of permanent majority lose is very low. But it is a severe enough problem that worth special care. We strongly suggest you to read the [disaster recovery documentation][disaster-recovery] and prepare for permanent majority lose before you put etcd into production.
## Do Not Use Public Discovery Service For Runtime Reconfiguration
The public discovery service should only be used for bootstrapping a cluster. To join member into an existing cluster, you should use runtime reconfiguration API.
Discovery service is designed for bootstrapping an etcd cluster in the cloud environment, when you do not know the IP addresses of all the members beforehand. After you successfully bootstrap a cluster, the IP addresses of all the members are known. Technically, you should not need the discovery service any more.
It seems that using public discovery service is a convenient way to do runtime reconfiguration, after all discovery service already has all the cluster configuration information. However relying on public discovery service brings troubles:
1. it introduces external dependencies for the entire life-cycle of your cluster, not just bootstrap time. If there is a network issue between your cluster and public discovery service, your cluster will suffer from it.
2. public discovery service must reflect correct runtime configuration of your cluster during it life-cycle. It has to provide security mechanism to avoid bad actions, and it is hard.
3. public discovery service has to keep tens of thousands of cluster configurations. Our public discovery service backend is not ready for that workload.
If you want to have a discovery service that supports runtime reconfiguration, the best choice is to build your private one.
[add-member]: runtime-configuration.md#add-a-new-member
[disaster-recovery]: admin_guide.md#disaster-recovery

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@ -1,58 +1,34 @@
# Security Model
# Reading and Writing over HTTPS
etcd supports SSL/TLS as well as authentication through client certificates, both for clients to server as well as peer (server to server / cluster) communication.
## Transport Security with HTTPS
To get up and running you first need to have a CA certificate and a signed key pair for one member. It is recommended to create and sign a new key pair for every member in a cluster.
Etcd supports SSL/TLS and client cert authentication for clients to server, as well as server to server communication.
For convenience, the [cfssl] tool provides an easy interface to certificate generation, and we provide an example using the tool [here][tls-setup]. You can also examine this [alternative guide to generating self-signed key pairs][tls-guide].
First, you need to have a CA cert `clientCA.crt` and signed key pair `client.crt`, `client.key`.
This site has a good reference for how to generate self-signed key pairs:
http://www.g-loaded.eu/2005/11/10/be-your-own-ca/
Or you could use [etcd-ca](https://github.com/coreos/etcd-ca) to generate certs and keys.
## Basic setup
For testing you can use the certificates in the `fixtures/ca` directory.
etcd takes several certificate related configuration options, either through command-line flags or environment variables:
**Client-to-server communication:**
`--cert-file=<path>`: Certificate used for SSL/TLS connections **to** etcd. When this option is set, you can set advertise-client-urls using HTTPS schema.
`--key-file=<path>`: Key for the certificate. Must be unencrypted.
`--client-cert-auth`: When this is set etcd will check all incoming HTTPS requests for a client certificate signed by the trusted CA, requests that don't supply a valid client certificate will fail.
`--trusted-ca-file=<path>`: Trusted certificate authority.
**Peer (server-to-server / cluster) communication:**
The peer options work the same way as the client-to-server options:
`--peer-cert-file=<path>`: Certificate used for SSL/TLS connections between peers. This will be used both for listening on the peer address as well as sending requests to other peers.
`--peer-key-file=<path>`: Key for the certificate. Must be unencrypted.
`--peer-client-cert-auth`: When set, etcd will check all incoming peer requests from the cluster for valid client certificates signed by the supplied CA.
`--peer-trusted-ca-file=<path>`: Trusted certificate authority.
If either a client-to-server or peer certificate is supplied the key must also be set. All of these configuration options are also available through the environment variables, `ETCD_CA_FILE`, `ETCD_PEER_CA_FILE` and so on.
## Example 1: Client-to-server transport security with HTTPS
For this you need your CA certificate (`ca.crt`) and signed key pair (`server.crt`, `server.key`) ready.
Let us configure etcd to provide simple HTTPS transport security step by step:
Let's configure etcd to use this keypair:
```sh
$ etcd -name infra0 -data-dir infra0 \
-cert-file=/path/to/server.crt -key-file=/path/to/server.key \
-advertise-client-urls=https://127.0.0.1:2379 -listen-client-urls=https://127.0.0.1:2379
./etcd -f -name machine0 -data-dir machine0 -cert-file=./fixtures/ca/server.crt -key-file=./fixtures/ca/server.key.insecure
```
This should start up fine and you can now test the configuration by speaking HTTPS to etcd:
There are a few new options we're using:
* `-f` - forces a new machine configuration, even if an existing configuration is found. (WARNING: data loss!)
* `-cert-file` and `-key-file` specify the location of the cert and key files to be used for for transport layer security between the client and server.
You can now test the configuration using HTTPS:
```sh
$ curl --cacert /path/to/ca.crt https://127.0.0.1:2379/v2/keys/foo -XPUT -d value=bar -v
curl --cacert ./fixtures/ca/server-chain.pem https://127.0.0.1:4001/v2/keys/foo -XPUT -d value=bar -v
```
You should be able to see the handshake succeed. Because we use self-signed certificates with our own certificate authorities you need to provide the CA to curl using the `--cacert` option. Another possibility would be to add your CA certificate to the trusted certificates on your system (usually in `/etc/ssl/certs`).
You should be able to see the handshake succeed.
**OSX 10.9+ Users**: curl 7.30.0 on OSX 10.9+ doesn't understand certificates passed in on the command line.
Instead you must import the dummy ca.crt directly into the keychain or add the `-k` flag to curl to ignore errors.
@ -60,27 +36,42 @@ If you want to test without the `-k` flag run `open ./fixtures/ca/ca.crt` and fo
Please remove this certificate after you are done testing!
If you know of a workaround let us know.
## Example 2: Client-to-server authentication with HTTPS client certificates
For now we've given the etcd client the ability to verify the server identity and provide transport security. We can however also use client certificates to prevent unauthorized access to etcd.
The clients will provide their certificates to the server and the server will check whether the cert is signed by the supplied CA and decide whether to serve the request.
You need the same files mentioned in the first example for this, as well as a key pair for the client (`client.crt`, `client.key`) signed by the same certificate authority.
```sh
$ etcd -name infra0 -data-dir infra0 \
-client-cert-auth -trusted-ca-file=/path/to/ca.crt -cert-file=/path/to/server.crt -key-file=/path/to/server.key \
-advertise-client-urls https://127.0.0.1:2379 -listen-client-urls https://127.0.0.1:2379
```
...
SSLv3, TLS handshake, Finished (20):
...
```
Now try the same request as above to this server:
And also the response from the etcd server:
```sh
$ curl --cacert /path/to/ca.crt https://127.0.0.1:2379/v2/keys/foo -XPUT -d value=bar -v
```json
{
"action": "set",
"key": "/foo",
"modifiedIndex": 3,
"value": "bar"
}
```
The request should be rejected by the server:
## Authentication with HTTPS Client Certificates
We can also do authentication using CA certs.
The clients will provide their cert to the server and the server will check whether the cert is signed by the CA and decide whether to serve the request.
```sh
./etcd -f -name machine0 -data-dir machine0 -ca-file=./fixtures/ca/ca.crt -cert-file=./fixtures/ca/server.crt -key-file=./fixtures/ca/server.key.insecure
```
```-ca-file``` is the path to the CA cert.
Try the same request to this server:
```sh
curl --cacert ./fixtures/ca/server-chain.pem https://127.0.0.1:4001/v2/keys/foo -XPUT -d value=bar -v
```
The request should be rejected by the server.
```
...
@ -88,14 +79,13 @@ routines:SSL3_READ_BYTES:sslv3 alert bad certificate
...
```
To make it succeed, we need to give the CA signed client certificate to the server:
We need to give the CA signed cert to the server.
```sh
$ curl --cacert /path/to/ca.crt --cert /path/to/client.crt --key /path/to/client.key \
-L https://127.0.0.1:2379/v2/keys/foo -XPUT -d value=bar -v
curl --key ./fixtures/ca/server2.key.insecure --cert ./fixtures/ca/server2.crt --cacert ./fixtures/ca/server-chain.pem -L https://127.0.0.1:4001/v2/keys/foo -XPUT -d value=bar -v
```
You should be able to see:
You should able to see:
```
...
@ -118,49 +108,7 @@ And also the response from the server:
}
```
## Example 3: Transport security & client certificates in a cluster
etcd supports the same model as above for **peer communication**, that means the communication between etcd members in a cluster.
Assuming we have our `ca.crt` and two members with their own keypairs (`member1.crt` & `member1.key`, `member2.crt` & `member2.key`) signed by this CA, we launch etcd as follows:
```sh
DISCOVERY_URL=... # from https://discovery.etcd.io/new
# member1
$ etcd -name infra1 -data-dir infra1 \
-peer-client-cert-auth -peer-trusted-ca-file=/path/to/ca.crt -peer-cert-file=/path/to/member1.crt -peer-key-file=/path/to/member1.key \
-initial-advertise-peer-urls=https://10.0.1.10:2380 -listen-peer-urls=https://10.0.1.10:2380 \
-discovery ${DISCOVERY_URL}
# member2
$ etcd -name infra2 -data-dir infra2 \
-peer-client-cert-auth -peer-trusted-ca-file=/path/to/ca.crt -peer-cert-file=/path/to/member2.crt -peer-key-file=/path/to/member2.key \
-initial-advertise-peer-urls=https://10.0.1.11:2380 -listen-peer-urls=https://10.0.1.11:2380 \
-discovery ${DISCOVERY_URL}
```
The etcd members will form a cluster and all communication between members in the cluster will be encrypted and authenticated using the client certificates. You will see in the output of etcd that the addresses it connects to use HTTPS.
## Notes For etcd Proxy
etcd proxy terminates the TLS from its client if the connection is secure, and uses proxy's own key/cert specified in `--peer-key-file` and `--peer-cert-file` to communicate with etcd members.
The proxy communicates with etcd members through both the `--advertise-client-urls` and `--advertise-peer-urls` of a given member. It forwards client requests to etcd members advertised client urls, and it syncs the initial cluster configuration through etcd members advertised peer urls.
When client authentication is enabled for an etcd member, the administrator must ensure that the peer certificate specified in the proxy's `--peer-cert-file` option is valid for that authentication. The proxy's peer certificate must also be valid for peer authentication if peer authentication is enabled.
## Frequently Asked Questions
### My cluster is not working with peer tls configuration?
The internal protocol of etcd v2.0.x uses a lot of short-lived HTTP connections.
So, when enabling TLS you may need to increase the heartbeat interval and election timeouts to reduce internal cluster connection churn.
A reasonable place to start are these values: ` --heartbeat-interval 500 --election-timeout 2500`.
These issues are resolved in the etcd v2.1.x series of releases which uses fewer connections.
### I'm seeing a SSLv3 alert handshake failure when using SSL client authentication?
### Why SSLv3 alert handshake failure when using SSL client auth?
The `crypto/tls` package of `golang` checks the key usage of the certificate public key before using it.
To use the certificate public key to do client auth, we need to add `clientAuth` to `Extended Key Usage` when creating the certificate public key.
@ -179,15 +127,5 @@ Add the following section to your openssl.cnf:
When creating the cert be sure to reference it in the `-extensions` flag:
```
$ openssl ca -config openssl.cnf -policy policy_anything -extensions ssl_client -out certs/machine.crt -infiles machine.csr
openssl ca -config openssl.cnf -policy policy_anything -extensions ssl_client -out certs/machine.crt -infiles machine.csr
```
### With peer certificate authentication I receive "certificate is valid for 127.0.0.1, not $MY_IP"
Make sure that you sign your certificates with a Subject Name your member's public IP address. The `etcd-ca` tool for example provides an `--ip=` option for its `new-cert` command.
If you need your certificate to be signed for your member's FQDN in its Subject Name then you could use Subject Alternative Names (short IP SANs) to add your IP address. The `etcd-ca` tool provides `--domain=` option for its `new-cert` command, and openssl can make [it][alt-name] too.
[cfssl]: https://github.com/cloudflare/cfssl
[tls-setup]: /hack/tls-setup
[tls-guide]: https://github.com/coreos/docs/blob/master/os/generate-self-signed-certificates.md
[alt-name]: http://wiki.cacert.org/FAQ/subjectAltName

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@ -1,55 +1,53 @@
# Tuning
## Tuning
The default settings in etcd should work well for installations on a local network where the average network latency is low.
However, when using etcd across multiple data centers or over networks with high latency you may need to tweak the heartbeat interval and election timeout settings.
The network isn't the only source of latency. Each request and response may be impacted by slow disks on both the leader and follower. Each of these timeouts represents the total time from request to successful response from the other machine.
## Time Parameters
### Time Parameters
The underlying distributed consensus protocol relies on two separate time parameters to ensure that nodes can handoff leadership if one stalls or goes offline.
The first parameter is called the *Heartbeat Interval*.
This is the frequency with which the leader will notify followers that it is still the leader.
For best practices, the parameter should be set around round-trip time between members.
By default, etcd uses a `100ms` heartbeat interval.
etcd batches commands together for higher throughput so this heartbeat interval is also a delay for how long it takes for commands to be committed.
By default, etcd uses a `50ms` heartbeat interval.
The second parameter is the *Election Timeout*.
This timeout is how long a follower node will go without hearing a heartbeat before attempting to become leader itself.
By default, etcd uses a `1000ms` election timeout.
By default, etcd uses a `200ms` election timeout.
Adjusting these values is a trade off.
The value of heartbeat interval is recommended to be around the maximum of average round-trip time (RTT) between members, normally around 0.5-1.5x the round-trip time.
If heartbeat interval is too low, etcd will send unnecessary messages that increase the usage of CPU and network resources.
On the other side, a too high heartbeat interval leads to high election timeout. Higher election timeout takes longer time to detect a leader failure.
The easiest way to measure round-trip time (RTT) is to use [PING utility][ping].
Lowering the heartbeat interval will cause individual commands to be committed faster but it will lower the overall throughput of etcd.
If your etcd instances have low utilization then lowering the heartbeat interval can improve your command response time.
The election timeout should be set based on the heartbeat interval and average round-trip time between members.
Election timeouts must be at least 10 times the round-trip time so it can account for variance in your network.
For example, if the round-trip time between your members is 10ms then you should have at least a 100ms election timeout.
The election timeout should be set based on the heartbeat interval and your network ping time between nodes.
Election timeouts should be at least 10 times your ping time so it can account for variance in your network.
For example, if the ping time between your nodes is 10ms then you should have at least a 100ms election timeout.
You should also set your election timeout to at least 5 to 10 times your heartbeat interval to account for variance in leader replication.
For a heartbeat interval of 50ms you should set your election timeout to at least 250ms - 500ms.
The upper limit of election timeout is 50000ms (50s), which should only be used when deploying a globally-distributed etcd cluster.
A reasonable round-trip time for the continental United States is 130ms, and the time between US and Japan is around 350-400ms.
If your network has uneven performance or regular packet delays/loss then it is possible that a couple of retries may be necessary to successfully send a packet. So 5s is a safe upper limit of global round-trip time.
As the election timeout should be an order of magnitude bigger than broadcast time, in the case of ~5s for a globally distributed cluster, then 50 seconds becomes a reasonable maximum.
The heartbeat interval and election timeout value should be the same for all members in one cluster. Setting different values for etcd members may disrupt cluster stability.
You should also set your election timeout to at least 4 to 5 times your heartbeat interval to account for variance in leader replication.
For a heartbeat interval of 50ms you should set your election timeout to at least 200ms - 250ms.
You can override the default values on the command line:
```sh
# Command line arguments:
$ etcd -heartbeat-interval=100 -election-timeout=500
$ etcd -peer-heartbeat-interval=100 -peer-election-timeout=500
# Environment variables:
$ ETCD_HEARTBEAT_INTERVAL=100 ETCD_ELECTION_TIMEOUT=500 etcd
$ ETCD_PEER_HEARTBEAT_INTERVAL=100 ETCD_PEER_ELECTION_TIMEOUT=500 etcd
```
Or you can set the values within the configuration file:
```toml
[peer]
heartbeat_interval = 100
election_timeout = 100
```
The values are specified in milliseconds.
## Snapshots
### Snapshots
etcd appends all key changes to a log file.
This log grows forever and is a complete linear history of every change made to the keys.
@ -72,4 +70,24 @@ $ etcd -snapshot-count=5000
$ ETCD_SNAPSHOT_COUNT=5000 etcd
```
[ping]: https://en.wikipedia.org/wiki/Ping_(networking_utility)
Or you can change the setting in the configuration file:
```toml
snapshot_count = 5000
```
You can also disable snapshotting by adding the following to your command line:
```sh
# Command line arguments:
$ etcd -snapshot false
# Environment variables:
$ ETCD_SNAPSHOT=false etcd
```
You can also disable snapshotting within the configuration file:
```toml
snapshot = false
```

17
Documentation/upgrade.md Normal file
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@ -0,0 +1,17 @@
# Upgrading an Existing Cluster
etcd clusters can be upgraded by doing a rolling upgrade or all at once. We make every effort to test this process, but please be sure to backup your data [by etcd-dump](https://github.com/AaronO/etcd-dump), or make a copy of data directory beforehand.
## Upgrade Process
- Stop the old etcd processes
- Upgrade the etcd binary
- Restart the etcd instance using the original --name, --address, --peer-address and --data-dir.
## Rolling Upgrade
During an upgrade, etcd clusters are designed to continue working in a mix of old and new versions. It's recommended to converge on the new version quickly. Using new API features before the entire cluster has been upgraded is only supported as a best effort. Each instance's version can be found with `curl http://127.0.0.1:4001/version`.
## All at Once
If downtime is not an issue, the easiest way to upgrade your cluster is to shutdown all of the etcd instances and restart them with the new binary. The current state of the cluster is saved to disk and will be loaded into the cluster when it restarts.

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@ -1,116 +0,0 @@
# Upgrade etcd to 2.1
In the general case, upgrading from etcd 2.0 to 2.1 can be a zero-downtime, rolling upgrade:
- one by one, stop the etcd v2.0 processes and replace them with etcd v2.1 processes
- after you are running all v2.1 processes, new features in v2.1 are available to the cluster
Before [starting an upgrade](#upgrade-procedure), read through the rest of this guide to prepare.
## Upgrade Checklists
### Upgrade Requirements
To upgrade an existing etcd deployment to 2.1, you must be running 2.0. If youre running a version of etcd before 2.0, you must upgrade to [2.0][v2.0] before upgrading to 2.1.
Also, to ensure a smooth rolling upgrade, your running cluster must be healthy. You can check the health of the cluster by using `etcdctl cluster-health` command.
### Preparedness
Before upgrading etcd, always test the services relying on etcd in a staging environment before deploying the upgrade to the production environment.
You might also want to [backup your data directory][backup-datastore] for a potential [downgrade](#downgrade).
etcd 2.1 introduces a new [authentication][auth] feature, which is disabled by default. If your deployment depends on these, you may want to test the auth features before enabling them in production.
### Mixed Versions
While upgrading, an etcd cluster supports mixed versions of etcd members. The cluster is only considered upgraded once all its members are upgraded to 2.1.
Internally, etcd members negotiate with each other to determine the overall etcd cluster version, which controls the reported cluster version and the supported features. For example, if you are mid-upgrade, any 2.1 features (such as the the authentication feature mentioned above) wont be available.
### Limitations
If you encounter any issues during the upgrade, you can attempt to restart the etcd process in trouble using a newer v2.1 binary to solve the problem. One known issue is that etcd v2.0.0 and v2.0.2 may panic during rolling upgrades due to an existing bug, which has been fixed since etcd v2.0.3.
It might take up to 2 minutes for the newly upgraded member to catch up with the existing cluster when the total data size is larger than 50MB (You can check the size of the existing snapshot to know about the rough data size). In other words, it is safest to wait for 2 minutes before upgrading the next member.
If you have even more data, this might take more time. If you have a data size larger than 100MB you should contact us before upgrading, so we can make sure the upgrades work smoothly.
### Downgrade
If all members have been upgraded to v2.1, the cluster will be upgraded to v2.1, and downgrade is **not possible**. If any member is still v2.0, the cluster will remain in v2.0, and you can go back to use v2.0 binary.
Please [backup your data directory][backup-datastore] of all etcd members if you want to downgrade the cluster, even if it is upgraded.
### Upgrade Procedure
#### 1. Check upgrade requirements.
```
$ etcdctl cluster-health
cluster is healthy
member 6e3bd23ae5f1eae0 is healthy
member 924e2e83e93f2560 is healthy
member a8266ecf031671f3 is healthy
$ curl http://127.0.0.1:4001/version
etcd 2.0.x
```
#### 2. Stop the existing etcd process
You will see similar error logging from other etcd processes in your cluster. This is normal, since you just shut down a member.
```
2015/06/23 15:45:09 sender: error posting to 6e3bd23ae5f1eae0: dial tcp 127.0.0.1:7002: connection refused
2015/06/23 15:45:09 sender: the connection with 6e3bd23ae5f1eae0 became inactive
2015/06/23 15:45:11 rafthttp: encountered error writing to server log stream: write tcp 127.0.0.1:53783: broken pipe
2015/06/23 15:45:11 rafthttp: server streaming to 6e3bd23ae5f1eae0 at term 2 has been stopped
2015/06/23 15:45:11 stream: error sending message: stopped
2015/06/23 15:45:11 stream: stopping the stream server...
```
You could [backup your data directory][backup-datastore] for data safety.
```
$ etcdctl backup \
--data-dir /var/lib/etcd \
--backup-dir /tmp/etcd_backup
```
#### 3. Drop-in etcd v2.1 binary and start the new etcd process
You will see the etcd publish its information to the cluster.
```
2015/06/23 15:45:39 etcdserver: published {Name:infra2 ClientURLs:[http://localhost:4002]} to cluster e9c7614f68f35fb2
```
You could verify the cluster becomes healthy.
```
$ etcdctl cluster-health
cluster is healthy
member 6e3bd23ae5f1eae0 is healthy
member 924e2e83e93f2560 is healthy
member a8266ecf031671f3 is healthy
```
#### 4. Repeat step 2 to step 3 for all other members
#### 5. Finish
When all members are upgraded, you will see the cluster is upgraded to 2.1 successfully:
```
2015/06/23 15:46:35 etcdserver: updated the cluster version from 2.0.0 to 2.1.0
```
```
$ curl http://127.0.0.1:4001/version
{"etcdserver":"2.1.x","etcdcluster":"2.1.0"}
```
[auth]: auth_api.md
[backup-datastore]: admin_guide.md#backing-up-the-datastore
[v2.0]: https://github.com/coreos/etcd/releases/tag/v2.0.13

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@ -1,132 +0,0 @@
# Upgrade etcd from 2.1 to 2.2
In the general case, upgrading from etcd 2.1 to 2.2 can be a zero-downtime, rolling upgrade:
- one by one, stop the etcd v2.1 processes and replace them with etcd v2.2 processes
- after you are running all v2.2 processes, new features in v2.2 are available to the cluster
Before [starting an upgrade](#upgrade-procedure), read through the rest of this guide to prepare.
## Upgrade Checklists
### Upgrade Requirement
To upgrade an existing etcd deployment to 2.2, you must be running 2.1. If youre running a version of etcd before 2.1, you must upgrade to [2.1][v2.1] before upgrading to 2.2.
Also, to ensure a smooth rolling upgrade, your running cluster must be healthy. You can check the health of the cluster by using `etcdctl cluster-health` command.
### Preparedness
Before upgrading etcd, always test the services relying on etcd in a staging environment before deploying the upgrade to the production environment.
You might also want to [backup the data directory][backup-datastore] for a potential [downgrade].
### Mixed Versions
While upgrading, an etcd cluster supports mixed versions of etcd members. The cluster is only considered upgraded once all its members are upgraded to 2.2.
Internally, etcd members negotiate with each other to determine the overall etcd cluster version, which controls the reported cluster version and the supported features.
### Limitations
If you have a data size larger than 100MB you should contact us before upgrading, so we can make sure the upgrades work smoothly.
Every etcd 2.2 member will do health checking across the cluster periodically. etcd 2.1 member does not support health checking. During the upgrade, etcd 2.2 member will log warning about the unhealthy state of etcd 2.1 member. You can ignore the warning.
### Downgrade
If all members have been upgraded to v2.2, the cluster will be upgraded to v2.2, and downgrade is **not possible**. If any member is still v2.1, the cluster will remain in v2.1, and you can go back to use v2.1 binary.
Please [backup the data directory][backup-datastore] of all etcd members if you want to downgrade the cluster, even if it is upgraded.
### Upgrade Procedure
In the example, we upgrade a three member v2.1 cluster running on local machine.
#### 1. Check upgrade requirements.
```
$ etcdctl cluster-health
member 6e3bd23ae5f1eae0 is healthy: got healthy result from http://localhost:22379
member 924e2e83e93f2560 is healthy: got healthy result from http://localhost:32379
member a8266ecf031671f3 is healthy: got healthy result from http://localhost:12379
cluster is healthy
$ curl http://localhost:4001/version
{"etcdserver":"2.1.x","etcdcluster":"2.1.0"}
```
#### 2. Stop the existing etcd process
You will see similar error logging from other etcd processes in your cluster. This is normal, since you just shut down a member and the connection is broken.
```
2015/09/2 09:48:35 etcdserver: failed to reach the peerURL(http://localhost:12380) of member a8266ecf031671f3 (Get http://localhost:12380/version: dial tcp [::1]:12380: getsockopt: connection refused)
2015/09/2 09:48:35 etcdserver: cannot get the version of member a8266ecf031671f3 (Get http://localhost:12380/version: dial tcp [::1]:12380: getsockopt: connection refused)
2015/09/2 09:48:35 rafthttp: failed to write a8266ecf031671f3 on stream Message (write tcp 127.0.0.1:32380->127.0.0.1:64394: write: broken pipe)
2015/09/2 09:48:35 rafthttp: failed to write a8266ecf031671f3 on pipeline (dial tcp [::1]:12380: getsockopt: connection refused)
2015/09/2 09:48:40 etcdserver: failed to reach the peerURL(http://localhost:7001) of member a8266ecf031671f3 (Get http://localhost:7001/version: dial tcp [::1]:12380: getsockopt: connection refused)
2015/09/2 09:48:40 etcdserver: cannot get the version of member a8266ecf031671f3 (Get http://localhost:12380/version: dial tcp [::1]:12380: getsockopt: connection refused)
2015/09/2 09:48:40 rafthttp: failed to heartbeat a8266ecf031671f3 on stream MsgApp v2 (write tcp 127.0.0.1:32380->127.0.0.1:64393: write: broken pipe)
```
You will see logging output like this from ungraded member due to a mixed version cluster. You can ignore this while upgrading.
```
2015/09/2 09:48:45 etcdserver: the etcd version 2.1.2+git is not up-to-date
2015/09/2 09:48:45 etcdserver: member a8266ecf031671f3 has a higher version &{2.2.0-rc.0+git 2.1.0}
```
You will also see logging output like this from the newly upgraded member, since etcd 2.1 member does not support health checking. You can ignore this while upgrading.
```
2015-09-02 09:55:42.691384 W | rafthttp: the connection to peer 6e3bd23ae5f1eae0 is unhealthy
2015-09-02 09:55:42.705626 W | rafthttp: the connection to peer 924e2e83e93f2560 is unhealthy
```
[Backup your data directory][backup-datastore] for data safety.
```
$ etcdctl backup \
--data-dir /var/lib/etcd \
--backup-dir /tmp/etcd_backup
```
#### 3. Drop-in etcd v2.2 binary and start the new etcd process
Now, you can start the etcd v2.2 binary with the previous configuration.
You will see the etcd start and publish its information to the cluster.
```
2015-09-02 09:56:46.117609 I | etcdserver: published {Name:infra2 ClientURLs:[http://localhost:22380]} to cluster e9c7614f68f35fb2
```
You could verify the cluster becomes healthy.
```
$ etcdctl cluster-health
member 6e3bd23ae5f1eae0 is healthy: got healthy result from http://localhost:22379
member 924e2e83e93f2560 is healthy: got healthy result from http://localhost:32379
member a8266ecf031671f3 is healthy: got healthy result from http://localhost:12379
cluster is healthy
```
#### 4. Repeat step 2 to step 3 for all other members
#### 5. Finish
When all members are upgraded, you will see the cluster is upgraded to 2.2 successfully:
```
2015-09-02 09:56:54.896848 N | etcdserver: updated the cluster version from 2.1 to 2.2
```
```
$ curl http://127.0.0.1:4001/version
{"etcdserver":"2.2.x","etcdcluster":"2.2.0"}
```
[backup-datastore]: admin_guide.md#backing-up-the-datastore
[downgrade]: #downgrade
[v2.1]: https://github.com/coreos/etcd/releases/tag/v2.1.2

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@ -1,121 +0,0 @@
## Upgrade etcd from 2.2 to 2.3
In the general case, upgrading from etcd 2.2 to 2.3 can be a zero-downtime, rolling upgrade:
- one by one, stop the etcd v2.2 processes and replace them with etcd v2.3 processes
- after running all v2.3 processes, new features in v2.3 are available to the cluster
Before [starting an upgrade](#upgrade-procedure), read through the rest of this guide to prepare.
### Upgrade Checklists
#### Upgrade Requirements
To upgrade an existing etcd deployment to 2.3, the running cluster must be 2.2 or greater. If it's before 2.2, please upgrade to [2.2](https://github.com/coreos/etcd/releases/tag/v2.2.0) before upgrading to 2.3.
Also, to ensure a smooth rolling upgrade, the running cluster must be healthy. You can check the health of the cluster by using the `etcdctl cluster-health` command.
#### Preparation
Before upgrading etcd, always test the services relying on etcd in a staging environment before deploying the upgrade to the production environment.
Before beginning, [backup the etcd data directory](admin_guide.md#backing-up-the-datastore). Should something go wrong with the upgrade, it is possible to use this backup to[downgrade](#downgrade) back to existing etcd version.
#### Mixed Versions
While upgrading, an etcd cluster supports mixed versions of etcd members, and operates with the protocol of the lowest common version. The cluster is only considered upgraded once all of its members are upgraded to version 2.3. Internally, etcd members negotiate with each other to determine the overall cluster version, which controls the reported version and the supported features.
#### Limitations
It might take up to 2 minutes for the newly upgraded member to catch up with the existing cluster when the total data size is larger than 50MB. Check the size of a recent snapshot to estimate the total data size. In other words, it is safest to wait for 2 minutes between upgrading each member.
For a much larger total data size, 100MB or more , this one-time process might take even more time. Administrators of very large etcd clusters of this magnitude can feel free to contact the [etcd team][etcd-contact] before upgrading, and well be happy to provide advice on the procedure.
#### Downgrade
If all members have been upgraded to v2.3, the cluster will be upgraded to v2.3, and downgrade from this completed state is **not possible**. If any single member is still v2.2, however, the cluster and its operations remains “v2.2”, and it is possible from this mixed cluster state to return to using a v2.2 etcd binary on all members.
Please [backup the data directory](admin_guide.md#backing-up-the-datastore) of all etcd members to make downgrading the cluster possible even after it has been completely upgraded.
### Upgrade Procedure
This example details the upgrade of a three-member v2.2 ectd cluster running on a local machine.
#### 1. Check upgrade requirements.
Is the the cluster healthy and running v.2.2.x?
```
$ etcdctl cluster-health
member 6e3bd23ae5f1eae0 is healthy: got healthy result from http://localhost:22379
member 924e2e83e93f2560 is healthy: got healthy result from http://localhost:32379
member a8266ecf031671f3 is healthy: got healthy result from http://localhost:12379
cluster is healthy
$ curl http://localhost:4001/version
{"etcdserver":"2.2.x","etcdcluster":"2.2.0"}
```
#### 2. Stop the existing etcd process
When each etcd process is stopped, expected errors will be logged by other cluster members. This is normal since a cluster member connection has been (temporarily) broken:
```
2016-03-11 09:50:49.860319 E | rafthttp: failed to read 8211f1d0f64f3269 on stream Message (unexpected EOF)
2016-03-11 09:50:49.860335 I | rafthttp: the connection with 8211f1d0f64f3269 became inactive
2016-03-11 09:50:51.023804 W | etcdserver: failed to reach the peerURL(http://127.0.0.1:12380) of member 8211f1d0f64f3269 (Get http://127.0.0.1:12380/version: dial tcp 127.0.0.1:12380: getsockopt: connection refused)
2016-03-11 09:50:51.023821 W | etcdserver: cannot get the version of member 8211f1d0f64f3269 (Get http://127.0.0.1:12380/version: dial tcp 127.0.0.1:12380: getsockopt: connection refused)
```
Its a good idea at this point to [backup the etcd data directory](https://github.com/coreos/etcd/blob/7f7e2cc79d9c5c342a6eb1e48c386b0223cf934e/Documentation/admin_guide.md#backing-up-the-datastore) to provide a downgrade path should any problems occur:
```
$ etcdctl backup \
--data-dir /var/lib/etcd \
--backup-dir /tmp/etcd_backup
```
#### 3. Drop-in etcd v2.3 binary and start the new etcd process
The new v2.3 etcd will publish its information to the cluster:
```
09:58:25.938673 I | etcdserver: published {Name:infra1 ClientURLs:[http://localhost:12379]} to cluster 524400597fb1d5f6
```
Verify that each member, and then the entire cluster, becomes healthy with the new v2.3 etcd binary:
```
$ etcdctl cluster-health
member 6e3bd23ae5f1eae0 is healthy: got healthy result from http://localhost:22379
member 924e2e83e93f2560 is healthy: got healthy result from http://localhost:32379
member a8266ecf031671f3 is healthy: got healthy result from http://localhost:12379
cluster is healthy
```
Upgraded members will log warnings like the following until the entire cluster is upgraded. This is expected and will cease after all etcd cluster members are upgraded to v2.3:
```
2016-03-11 09:58:26.851837 W | etcdserver: the local etcd version 2.2.0 is not up-to-date
2016-03-11 09:58:26.851854 W | etcdserver: member c02c70ede158499f has a higher version 2.3.0
```
#### 4. Repeat step 2 to step 3 for all other members
#### 5. Finish
When all members are upgraded, the cluster will report upgrading to 2.3 successfully:
```
2016-03-11 10:03:01.583392 N | etcdserver: updated the cluster version from 2.2 to 2.3
```
```
$ curl http://127.0.0.1:4001/version
{"etcdserver":"2.3.x","etcdcluster":"2.3.0"}
```
[etcd-contact]: https://coreos.com/etcd/?

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This directory tree is generated automatically by godep.
Please do not edit.
See https://github.com/tools/godep for more information.

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/pkg
/bin

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include $(GOROOT)/src/Make.inc
TARG=bitbucket.org/ww/goautoneg
GOFILES=autoneg.go
include $(GOROOT)/src/Make.pkg
format:
gofmt -w *.go
docs:
gomake clean
godoc ${TARG} > README.txt

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PACKAGE
package goautoneg
import "bitbucket.org/ww/goautoneg"
HTTP Content-Type Autonegotiation.
The functions in this package implement the behaviour specified in
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
Copyright (c) 2011, Open Knowledge Foundation Ltd.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
Neither the name of the Open Knowledge Foundation Ltd. nor the
names of its contributors may be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
FUNCTIONS
func Negotiate(header string, alternatives []string) (content_type string)
Negotiate the most appropriate content_type given the accept header
and a list of alternatives.
func ParseAccept(header string) (accept []Accept)
Parse an Accept Header string returning a sorted list
of clauses
TYPES
type Accept struct {
Type, SubType string
Q float32
Params map[string]string
}
Structure to represent a clause in an HTTP Accept Header
SUBDIRECTORIES
.hg

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/*
HTTP Content-Type Autonegotiation.
The functions in this package implement the behaviour specified in
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
Copyright (c) 2011, Open Knowledge Foundation Ltd.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
Neither the name of the Open Knowledge Foundation Ltd. nor the
names of its contributors may be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package goautoneg
import (
"sort"
"strconv"
"strings"
)
// Structure to represent a clause in an HTTP Accept Header
type Accept struct {
Type, SubType string
Q float64
Params map[string]string
}
// For internal use, so that we can use the sort interface
type accept_slice []Accept
func (accept accept_slice) Len() int {
slice := []Accept(accept)
return len(slice)
}
func (accept accept_slice) Less(i, j int) bool {
slice := []Accept(accept)
ai, aj := slice[i], slice[j]
if ai.Q > aj.Q {
return true
}
if ai.Type != "*" && aj.Type == "*" {
return true
}
if ai.SubType != "*" && aj.SubType == "*" {
return true
}
return false
}
func (accept accept_slice) Swap(i, j int) {
slice := []Accept(accept)
slice[i], slice[j] = slice[j], slice[i]
}
// Parse an Accept Header string returning a sorted list
// of clauses
func ParseAccept(header string) (accept []Accept) {
parts := strings.Split(header, ",")
accept = make([]Accept, 0, len(parts))
for _, part := range parts {
part := strings.Trim(part, " ")
a := Accept{}
a.Params = make(map[string]string)
a.Q = 1.0
mrp := strings.Split(part, ";")
media_range := mrp[0]
sp := strings.Split(media_range, "/")
a.Type = strings.Trim(sp[0], " ")
switch {
case len(sp) == 1 && a.Type == "*":
a.SubType = "*"
case len(sp) == 2:
a.SubType = strings.Trim(sp[1], " ")
default:
continue
}
if len(mrp) == 1 {
accept = append(accept, a)
continue
}
for _, param := range mrp[1:] {
sp := strings.SplitN(param, "=", 2)
if len(sp) != 2 {
continue
}
token := strings.Trim(sp[0], " ")
if token == "q" {
a.Q, _ = strconv.ParseFloat(sp[1], 32)
} else {
a.Params[token] = strings.Trim(sp[1], " ")
}
}
accept = append(accept, a)
}
slice := accept_slice(accept)
sort.Sort(slice)
return
}
// Negotiate the most appropriate content_type given the accept header
// and a list of alternatives.
func Negotiate(header string, alternatives []string) (content_type string) {
asp := make([][]string, 0, len(alternatives))
for _, ctype := range alternatives {
asp = append(asp, strings.SplitN(ctype, "/", 2))
}
for _, clause := range ParseAccept(header) {
for i, ctsp := range asp {
if clause.Type == ctsp[0] && clause.SubType == ctsp[1] {
content_type = alternatives[i]
return
}
if clause.Type == ctsp[0] && clause.SubType == "*" {
content_type = alternatives[i]
return
}
if clause.Type == "*" && clause.SubType == "*" {
content_type = alternatives[i]
return
}
}
}
return
}

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@ -1,33 +0,0 @@
package goautoneg
import (
"testing"
)
var chrome = "application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"
func TestParseAccept(t *testing.T) {
alternatives := []string{"text/html", "image/png"}
content_type := Negotiate(chrome, alternatives)
if content_type != "image/png" {
t.Errorf("got %s expected image/png", content_type)
}
alternatives = []string{"text/html", "text/plain", "text/n3"}
content_type = Negotiate(chrome, alternatives)
if content_type != "text/html" {
t.Errorf("got %s expected text/html", content_type)
}
alternatives = []string{"text/n3", "text/plain"}
content_type = Negotiate(chrome, alternatives)
if content_type != "text/plain" {
t.Errorf("got %s expected text/plain", content_type)
}
alternatives = []string{"text/n3", "application/rdf+xml"}
content_type = Negotiate(chrome, alternatives)
if content_type != "text/n3" {
t.Errorf("got %s expected text/n3", content_type)
}
}

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@ -1,5 +0,0 @@
#*
*~
/tools/pass/pass
/tools/pcaptest/pcaptest
/tools/tcpdump/tcpdump

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@ -1,27 +0,0 @@
Copyright (c) 2009-2011 Andreas Krennmair. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Andreas Krennmair nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

View File

@ -1,11 +0,0 @@
# PCAP
This is a simple wrapper around libpcap for Go. Originally written by Andreas
Krennmair <ak@synflood.at> and only minorly touched up by Mark Smith <mark@qq.is>.
Please see the included pcaptest.go and tcpdump.go programs for instructions on
how to use this library.
Miek Gieben <miek@miek.nl> has created a more Go-like package and replaced functionality
with standard functions from the standard library. The package has also been renamed to
pcap.

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@ -1,527 +0,0 @@
package pcap
import (
"encoding/binary"
"fmt"
"net"
"reflect"
"strings"
)
const (
TYPE_IP = 0x0800
TYPE_ARP = 0x0806
TYPE_IP6 = 0x86DD
TYPE_VLAN = 0x8100
IP_ICMP = 1
IP_INIP = 4
IP_TCP = 6
IP_UDP = 17
)
const (
ERRBUF_SIZE = 256
// According to pcap-linktype(7).
LINKTYPE_NULL = 0
LINKTYPE_ETHERNET = 1
LINKTYPE_TOKEN_RING = 6
LINKTYPE_ARCNET = 7
LINKTYPE_SLIP = 8
LINKTYPE_PPP = 9
LINKTYPE_FDDI = 10
LINKTYPE_ATM_RFC1483 = 100
LINKTYPE_RAW = 101
LINKTYPE_PPP_HDLC = 50
LINKTYPE_PPP_ETHER = 51
LINKTYPE_C_HDLC = 104
LINKTYPE_IEEE802_11 = 105
LINKTYPE_FRELAY = 107
LINKTYPE_LOOP = 108
LINKTYPE_LINUX_SLL = 113
LINKTYPE_LTALK = 104
LINKTYPE_PFLOG = 117
LINKTYPE_PRISM_HEADER = 119
LINKTYPE_IP_OVER_FC = 122
LINKTYPE_SUNATM = 123
LINKTYPE_IEEE802_11_RADIO = 127
LINKTYPE_ARCNET_LINUX = 129
LINKTYPE_LINUX_IRDA = 144
LINKTYPE_LINUX_LAPD = 177
)
type addrHdr interface {
SrcAddr() string
DestAddr() string
Len() int
}
type addrStringer interface {
String(addr addrHdr) string
}
func decodemac(pkt []byte) uint64 {
mac := uint64(0)
for i := uint(0); i < 6; i++ {
mac = (mac << 8) + uint64(pkt[i])
}
return mac
}
// Decode decodes the headers of a Packet.
func (p *Packet) Decode() {
if len(p.Data) <= 14 {
return
}
p.Type = int(binary.BigEndian.Uint16(p.Data[12:14]))
p.DestMac = decodemac(p.Data[0:6])
p.SrcMac = decodemac(p.Data[6:12])
if len(p.Data) >= 15 {
p.Payload = p.Data[14:]
}
switch p.Type {
case TYPE_IP:
p.decodeIp()
case TYPE_IP6:
p.decodeIp6()
case TYPE_ARP:
p.decodeArp()
case TYPE_VLAN:
p.decodeVlan()
}
}
func (p *Packet) headerString(headers []interface{}) string {
// If there's just one header, return that.
if len(headers) == 1 {
if hdr, ok := headers[0].(fmt.Stringer); ok {
return hdr.String()
}
}
// If there are two headers (IPv4/IPv6 -> TCP/UDP/IP..)
if len(headers) == 2 {
// Commonly the first header is an address.
if addr, ok := p.Headers[0].(addrHdr); ok {
if hdr, ok := p.Headers[1].(addrStringer); ok {
return fmt.Sprintf("%s %s", p.Time, hdr.String(addr))
}
}
}
// For IP in IP, we do a recursive call.
if len(headers) >= 2 {
if addr, ok := headers[0].(addrHdr); ok {
if _, ok := headers[1].(addrHdr); ok {
return fmt.Sprintf("%s > %s IP in IP: ",
addr.SrcAddr(), addr.DestAddr(), p.headerString(headers[1:]))
}
}
}
var typeNames []string
for _, hdr := range headers {
typeNames = append(typeNames, reflect.TypeOf(hdr).String())
}
return fmt.Sprintf("unknown [%s]", strings.Join(typeNames, ","))
}
// String prints a one-line representation of the packet header.
// The output is suitable for use in a tcpdump program.
func (p *Packet) String() string {
// If there are no headers, print "unsupported protocol".
if len(p.Headers) == 0 {
return fmt.Sprintf("%s unsupported protocol %d", p.Time, int(p.Type))
}
return fmt.Sprintf("%s %s", p.Time, p.headerString(p.Headers))
}
// Arphdr is a ARP packet header.
type Arphdr struct {
Addrtype uint16
Protocol uint16
HwAddressSize uint8
ProtAddressSize uint8
Operation uint16
SourceHwAddress []byte
SourceProtAddress []byte
DestHwAddress []byte
DestProtAddress []byte
}
func (arp *Arphdr) String() (s string) {
switch arp.Operation {
case 1:
s = "ARP request"
case 2:
s = "ARP Reply"
}
if arp.Addrtype == LINKTYPE_ETHERNET && arp.Protocol == TYPE_IP {
s = fmt.Sprintf("%012x (%s) > %012x (%s)",
decodemac(arp.SourceHwAddress), arp.SourceProtAddress,
decodemac(arp.DestHwAddress), arp.DestProtAddress)
} else {
s = fmt.Sprintf("addrtype = %d protocol = %d", arp.Addrtype, arp.Protocol)
}
return
}
func (p *Packet) decodeArp() {
if len(p.Payload) < 8 {
return
}
pkt := p.Payload
arp := new(Arphdr)
arp.Addrtype = binary.BigEndian.Uint16(pkt[0:2])
arp.Protocol = binary.BigEndian.Uint16(pkt[2:4])
arp.HwAddressSize = pkt[4]
arp.ProtAddressSize = pkt[5]
arp.Operation = binary.BigEndian.Uint16(pkt[6:8])
if len(pkt) < int(8+2*arp.HwAddressSize+2*arp.ProtAddressSize) {
return
}
arp.SourceHwAddress = pkt[8 : 8+arp.HwAddressSize]
arp.SourceProtAddress = pkt[8+arp.HwAddressSize : 8+arp.HwAddressSize+arp.ProtAddressSize]
arp.DestHwAddress = pkt[8+arp.HwAddressSize+arp.ProtAddressSize : 8+2*arp.HwAddressSize+arp.ProtAddressSize]
arp.DestProtAddress = pkt[8+2*arp.HwAddressSize+arp.ProtAddressSize : 8+2*arp.HwAddressSize+2*arp.ProtAddressSize]
p.Headers = append(p.Headers, arp)
if len(pkt) >= int(8+2*arp.HwAddressSize+2*arp.ProtAddressSize) {
p.Payload = p.Payload[8+2*arp.HwAddressSize+2*arp.ProtAddressSize:]
}
}
// IPadr is the header of an IP packet.
type Iphdr struct {
Version uint8
Ihl uint8
Tos uint8
Length uint16
Id uint16
Flags uint8
FragOffset uint16
Ttl uint8
Protocol uint8
Checksum uint16
SrcIp []byte
DestIp []byte
}
func (p *Packet) decodeIp() {
if len(p.Payload) < 20 {
return
}
pkt := p.Payload
ip := new(Iphdr)
ip.Version = uint8(pkt[0]) >> 4
ip.Ihl = uint8(pkt[0]) & 0x0F
ip.Tos = pkt[1]
ip.Length = binary.BigEndian.Uint16(pkt[2:4])
ip.Id = binary.BigEndian.Uint16(pkt[4:6])
flagsfrags := binary.BigEndian.Uint16(pkt[6:8])
ip.Flags = uint8(flagsfrags >> 13)
ip.FragOffset = flagsfrags & 0x1FFF
ip.Ttl = pkt[8]
ip.Protocol = pkt[9]
ip.Checksum = binary.BigEndian.Uint16(pkt[10:12])
ip.SrcIp = pkt[12:16]
ip.DestIp = pkt[16:20]
pEnd := int(ip.Length)
if pEnd > len(pkt) {
pEnd = len(pkt)
}
if len(pkt) >= pEnd && int(ip.Ihl*4) < pEnd {
p.Payload = pkt[ip.Ihl*4 : pEnd]
} else {
p.Payload = []byte{}
}
p.Headers = append(p.Headers, ip)
p.IP = ip
switch ip.Protocol {
case IP_TCP:
p.decodeTcp()
case IP_UDP:
p.decodeUdp()
case IP_ICMP:
p.decodeIcmp()
case IP_INIP:
p.decodeIp()
}
}
func (ip *Iphdr) SrcAddr() string { return net.IP(ip.SrcIp).String() }
func (ip *Iphdr) DestAddr() string { return net.IP(ip.DestIp).String() }
func (ip *Iphdr) Len() int { return int(ip.Length) }
type Vlanhdr struct {
Priority byte
DropEligible bool
VlanIdentifier int
Type int // Not actually part of the vlan header, but the type of the actual packet
}
func (v *Vlanhdr) String() {
fmt.Sprintf("VLAN Priority:%d Drop:%v Tag:%d", v.Priority, v.DropEligible, v.VlanIdentifier)
}
func (p *Packet) decodeVlan() {
pkt := p.Payload
vlan := new(Vlanhdr)
if len(pkt) < 4 {
return
}
vlan.Priority = (pkt[2] & 0xE0) >> 13
vlan.DropEligible = pkt[2]&0x10 != 0
vlan.VlanIdentifier = int(binary.BigEndian.Uint16(pkt[:2])) & 0x0FFF
vlan.Type = int(binary.BigEndian.Uint16(p.Payload[2:4]))
p.Headers = append(p.Headers, vlan)
if len(pkt) >= 5 {
p.Payload = p.Payload[4:]
}
switch vlan.Type {
case TYPE_IP:
p.decodeIp()
case TYPE_IP6:
p.decodeIp6()
case TYPE_ARP:
p.decodeArp()
}
}
type Tcphdr struct {
SrcPort uint16
DestPort uint16
Seq uint32
Ack uint32
DataOffset uint8
Flags uint16
Window uint16
Checksum uint16
Urgent uint16
Data []byte
}
const (
TCP_FIN = 1 << iota
TCP_SYN
TCP_RST
TCP_PSH
TCP_ACK
TCP_URG
TCP_ECE
TCP_CWR
TCP_NS
)
func (p *Packet) decodeTcp() {
if len(p.Payload) < 20 {
return
}
pkt := p.Payload
tcp := new(Tcphdr)
tcp.SrcPort = binary.BigEndian.Uint16(pkt[0:2])
tcp.DestPort = binary.BigEndian.Uint16(pkt[2:4])
tcp.Seq = binary.BigEndian.Uint32(pkt[4:8])
tcp.Ack = binary.BigEndian.Uint32(pkt[8:12])
tcp.DataOffset = (pkt[12] & 0xF0) >> 4
tcp.Flags = binary.BigEndian.Uint16(pkt[12:14]) & 0x1FF
tcp.Window = binary.BigEndian.Uint16(pkt[14:16])
tcp.Checksum = binary.BigEndian.Uint16(pkt[16:18])
tcp.Urgent = binary.BigEndian.Uint16(pkt[18:20])
if len(pkt) >= int(tcp.DataOffset*4) {
p.Payload = pkt[tcp.DataOffset*4:]
}
p.Headers = append(p.Headers, tcp)
p.TCP = tcp
}
func (tcp *Tcphdr) String(hdr addrHdr) string {
return fmt.Sprintf("TCP %s:%d > %s:%d %s SEQ=%d ACK=%d LEN=%d",
hdr.SrcAddr(), int(tcp.SrcPort), hdr.DestAddr(), int(tcp.DestPort),
tcp.FlagsString(), int64(tcp.Seq), int64(tcp.Ack), hdr.Len())
}
func (tcp *Tcphdr) FlagsString() string {
var sflags []string
if 0 != (tcp.Flags & TCP_SYN) {
sflags = append(sflags, "syn")
}
if 0 != (tcp.Flags & TCP_FIN) {
sflags = append(sflags, "fin")
}
if 0 != (tcp.Flags & TCP_ACK) {
sflags = append(sflags, "ack")
}
if 0 != (tcp.Flags & TCP_PSH) {
sflags = append(sflags, "psh")
}
if 0 != (tcp.Flags & TCP_RST) {
sflags = append(sflags, "rst")
}
if 0 != (tcp.Flags & TCP_URG) {
sflags = append(sflags, "urg")
}
if 0 != (tcp.Flags & TCP_NS) {
sflags = append(sflags, "ns")
}
if 0 != (tcp.Flags & TCP_CWR) {
sflags = append(sflags, "cwr")
}
if 0 != (tcp.Flags & TCP_ECE) {
sflags = append(sflags, "ece")
}
return fmt.Sprintf("[%s]", strings.Join(sflags, " "))
}
type Udphdr struct {
SrcPort uint16
DestPort uint16
Length uint16
Checksum uint16
}
func (p *Packet) decodeUdp() {
if len(p.Payload) < 8 {
return
}
pkt := p.Payload
udp := new(Udphdr)
udp.SrcPort = binary.BigEndian.Uint16(pkt[0:2])
udp.DestPort = binary.BigEndian.Uint16(pkt[2:4])
udp.Length = binary.BigEndian.Uint16(pkt[4:6])
udp.Checksum = binary.BigEndian.Uint16(pkt[6:8])
p.Headers = append(p.Headers, udp)
p.UDP = udp
if len(p.Payload) >= 8 {
p.Payload = pkt[8:]
}
}
func (udp *Udphdr) String(hdr addrHdr) string {
return fmt.Sprintf("UDP %s:%d > %s:%d LEN=%d CHKSUM=%d",
hdr.SrcAddr(), int(udp.SrcPort), hdr.DestAddr(), int(udp.DestPort),
int(udp.Length), int(udp.Checksum))
}
type Icmphdr struct {
Type uint8
Code uint8
Checksum uint16
Id uint16
Seq uint16
Data []byte
}
func (p *Packet) decodeIcmp() *Icmphdr {
if len(p.Payload) < 8 {
return nil
}
pkt := p.Payload
icmp := new(Icmphdr)
icmp.Type = pkt[0]
icmp.Code = pkt[1]
icmp.Checksum = binary.BigEndian.Uint16(pkt[2:4])
icmp.Id = binary.BigEndian.Uint16(pkt[4:6])
icmp.Seq = binary.BigEndian.Uint16(pkt[6:8])
p.Payload = pkt[8:]
p.Headers = append(p.Headers, icmp)
return icmp
}
func (icmp *Icmphdr) String(hdr addrHdr) string {
return fmt.Sprintf("ICMP %s > %s Type = %d Code = %d ",
hdr.SrcAddr(), hdr.DestAddr(), icmp.Type, icmp.Code)
}
func (icmp *Icmphdr) TypeString() (result string) {
switch icmp.Type {
case 0:
result = fmt.Sprintf("Echo reply seq=%d", icmp.Seq)
case 3:
switch icmp.Code {
case 0:
result = "Network unreachable"
case 1:
result = "Host unreachable"
case 2:
result = "Protocol unreachable"
case 3:
result = "Port unreachable"
default:
result = "Destination unreachable"
}
case 8:
result = fmt.Sprintf("Echo request seq=%d", icmp.Seq)
case 30:
result = "Traceroute"
}
return
}
type Ip6hdr struct {
// http://www.networksorcery.com/enp/protocol/ipv6.htm
Version uint8 // 4 bits
TrafficClass uint8 // 8 bits
FlowLabel uint32 // 20 bits
Length uint16 // 16 bits
NextHeader uint8 // 8 bits, same as Protocol in Iphdr
HopLimit uint8 // 8 bits
SrcIp []byte // 16 bytes
DestIp []byte // 16 bytes
}
func (p *Packet) decodeIp6() {
if len(p.Payload) < 40 {
return
}
pkt := p.Payload
ip6 := new(Ip6hdr)
ip6.Version = uint8(pkt[0]) >> 4
ip6.TrafficClass = uint8((binary.BigEndian.Uint16(pkt[0:2]) >> 4) & 0x00FF)
ip6.FlowLabel = binary.BigEndian.Uint32(pkt[0:4]) & 0x000FFFFF
ip6.Length = binary.BigEndian.Uint16(pkt[4:6])
ip6.NextHeader = pkt[6]
ip6.HopLimit = pkt[7]
ip6.SrcIp = pkt[8:24]
ip6.DestIp = pkt[24:40]
if len(p.Payload) >= 40 {
p.Payload = pkt[40:]
}
p.Headers = append(p.Headers, ip6)
switch ip6.NextHeader {
case IP_TCP:
p.decodeTcp()
case IP_UDP:
p.decodeUdp()
case IP_ICMP:
p.decodeIcmp()
case IP_INIP:
p.decodeIp()
}
}
func (ip6 *Ip6hdr) SrcAddr() string { return net.IP(ip6.SrcIp).String() }
func (ip6 *Ip6hdr) DestAddr() string { return net.IP(ip6.DestIp).String() }
func (ip6 *Ip6hdr) Len() int { return int(ip6.Length) }

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@ -1,247 +0,0 @@
package pcap
import (
"bytes"
"testing"
"time"
)
var testSimpleTcpPacket *Packet = &Packet{
Data: []byte{
0x00, 0x00, 0x0c, 0x9f, 0xf0, 0x20, 0xbc, 0x30, 0x5b, 0xe8, 0xd3, 0x49,
0x08, 0x00, 0x45, 0x00, 0x01, 0xa4, 0x39, 0xdf, 0x40, 0x00, 0x40, 0x06,
0x55, 0x5a, 0xac, 0x11, 0x51, 0x49, 0xad, 0xde, 0xfe, 0xe1, 0xc5, 0xf7,
0x00, 0x50, 0xc5, 0x7e, 0x0e, 0x48, 0x49, 0x07, 0x42, 0x32, 0x80, 0x18,
0x00, 0x73, 0xab, 0xb1, 0x00, 0x00, 0x01, 0x01, 0x08, 0x0a, 0x03, 0x77,
0x37, 0x9c, 0x42, 0x77, 0x5e, 0x3a, 0x47, 0x45, 0x54, 0x20, 0x2f, 0x20,
0x48, 0x54, 0x54, 0x50, 0x2f, 0x31, 0x2e, 0x31, 0x0d, 0x0a, 0x48, 0x6f,
0x73, 0x74, 0x3a, 0x20, 0x77, 0x77, 0x77, 0x2e, 0x66, 0x69, 0x73, 0x68,
0x2e, 0x63, 0x6f, 0x6d, 0x0d, 0x0a, 0x43, 0x6f, 0x6e, 0x6e, 0x65, 0x63,
0x74, 0x69, 0x6f, 0x6e, 0x3a, 0x20, 0x6b, 0x65, 0x65, 0x70, 0x2d, 0x61,
0x6c, 0x69, 0x76, 0x65, 0x0d, 0x0a, 0x55, 0x73, 0x65, 0x72, 0x2d, 0x41,
0x67, 0x65, 0x6e, 0x74, 0x3a, 0x20, 0x4d, 0x6f, 0x7a, 0x69, 0x6c, 0x6c,
0x61, 0x2f, 0x35, 0x2e, 0x30, 0x20, 0x28, 0x58, 0x31, 0x31, 0x3b, 0x20,
0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x78, 0x38, 0x36, 0x5f, 0x36, 0x34,
0x29, 0x20, 0x41, 0x70, 0x70, 0x6c, 0x65, 0x57, 0x65, 0x62, 0x4b, 0x69,
0x74, 0x2f, 0x35, 0x33, 0x35, 0x2e, 0x32, 0x20, 0x28, 0x4b, 0x48, 0x54,
0x4d, 0x4c, 0x2c, 0x20, 0x6c, 0x69, 0x6b, 0x65, 0x20, 0x47, 0x65, 0x63,
0x6b, 0x6f, 0x29, 0x20, 0x43, 0x68, 0x72, 0x6f, 0x6d, 0x65, 0x2f, 0x31,
0x35, 0x2e, 0x30, 0x2e, 0x38, 0x37, 0x34, 0x2e, 0x31, 0x32, 0x31, 0x20,
0x53, 0x61, 0x66, 0x61, 0x72, 0x69, 0x2f, 0x35, 0x33, 0x35, 0x2e, 0x32,
0x0d, 0x0a, 0x41, 0x63, 0x63, 0x65, 0x70, 0x74, 0x3a, 0x20, 0x74, 0x65,
0x78, 0x74, 0x2f, 0x68, 0x74, 0x6d, 0x6c, 0x2c, 0x61, 0x70, 0x70, 0x6c,
0x69, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2f, 0x78, 0x68, 0x74, 0x6d,
0x6c, 0x2b, 0x78, 0x6d, 0x6c, 0x2c, 0x61, 0x70, 0x70, 0x6c, 0x69, 0x63,
0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2f, 0x78, 0x6d, 0x6c, 0x3b, 0x71, 0x3d,
0x30, 0x2e, 0x39, 0x2c, 0x2a, 0x2f, 0x2a, 0x3b, 0x71, 0x3d, 0x30, 0x2e,
0x38, 0x0d, 0x0a, 0x41, 0x63, 0x63, 0x65, 0x70, 0x74, 0x2d, 0x45, 0x6e,
0x63, 0x6f, 0x64, 0x69, 0x6e, 0x67, 0x3a, 0x20, 0x67, 0x7a, 0x69, 0x70,
0x2c, 0x64, 0x65, 0x66, 0x6c, 0x61, 0x74, 0x65, 0x2c, 0x73, 0x64, 0x63,
0x68, 0x0d, 0x0a, 0x41, 0x63, 0x63, 0x65, 0x70, 0x74, 0x2d, 0x4c, 0x61,
0x6e, 0x67, 0x75, 0x61, 0x67, 0x65, 0x3a, 0x20, 0x65, 0x6e, 0x2d, 0x55,
0x53, 0x2c, 0x65, 0x6e, 0x3b, 0x71, 0x3d, 0x30, 0x2e, 0x38, 0x0d, 0x0a,
0x41, 0x63, 0x63, 0x65, 0x70, 0x74, 0x2d, 0x43, 0x68, 0x61, 0x72, 0x73,
0x65, 0x74, 0x3a, 0x20, 0x49, 0x53, 0x4f, 0x2d, 0x38, 0x38, 0x35, 0x39,
0x2d, 0x31, 0x2c, 0x75, 0x74, 0x66, 0x2d, 0x38, 0x3b, 0x71, 0x3d, 0x30,
0x2e, 0x37, 0x2c, 0x2a, 0x3b, 0x71, 0x3d, 0x30, 0x2e, 0x33, 0x0d, 0x0a,
0x0d, 0x0a,
}}
func BenchmarkDecodeSimpleTcpPacket(b *testing.B) {
for i := 0; i < b.N; i++ {
testSimpleTcpPacket.Decode()
}
}
func TestDecodeSimpleTcpPacket(t *testing.T) {
p := testSimpleTcpPacket
p.Decode()
if p.DestMac != 0x00000c9ff020 {
t.Error("Dest mac", p.DestMac)
}
if p.SrcMac != 0xbc305be8d349 {
t.Error("Src mac", p.SrcMac)
}
if len(p.Headers) != 2 {
t.Error("Incorrect number of headers", len(p.Headers))
return
}
if ip, ipOk := p.Headers[0].(*Iphdr); ipOk {
if ip.Version != 4 {
t.Error("ip Version", ip.Version)
}
if ip.Ihl != 5 {
t.Error("ip header length", ip.Ihl)
}
if ip.Tos != 0 {
t.Error("ip TOS", ip.Tos)
}
if ip.Length != 420 {
t.Error("ip Length", ip.Length)
}
if ip.Id != 14815 {
t.Error("ip ID", ip.Id)
}
if ip.Flags != 0x02 {
t.Error("ip Flags", ip.Flags)
}
if ip.FragOffset != 0 {
t.Error("ip Fragoffset", ip.FragOffset)
}
if ip.Ttl != 64 {
t.Error("ip TTL", ip.Ttl)
}
if ip.Protocol != 6 {
t.Error("ip Protocol", ip.Protocol)
}
if ip.Checksum != 0x555A {
t.Error("ip Checksum", ip.Checksum)
}
if !bytes.Equal(ip.SrcIp, []byte{172, 17, 81, 73}) {
t.Error("ip Src", ip.SrcIp)
}
if !bytes.Equal(ip.DestIp, []byte{173, 222, 254, 225}) {
t.Error("ip Dest", ip.DestIp)
}
if tcp, tcpOk := p.Headers[1].(*Tcphdr); tcpOk {
if tcp.SrcPort != 50679 {
t.Error("tcp srcport", tcp.SrcPort)
}
if tcp.DestPort != 80 {
t.Error("tcp destport", tcp.DestPort)
}
if tcp.Seq != 0xc57e0e48 {
t.Error("tcp seq", tcp.Seq)
}
if tcp.Ack != 0x49074232 {
t.Error("tcp ack", tcp.Ack)
}
if tcp.DataOffset != 8 {
t.Error("tcp dataoffset", tcp.DataOffset)
}
if tcp.Flags != 0x18 {
t.Error("tcp flags", tcp.Flags)
}
if tcp.Window != 0x73 {
t.Error("tcp window", tcp.Window)
}
if tcp.Checksum != 0xabb1 {
t.Error("tcp checksum", tcp.Checksum)
}
if tcp.Urgent != 0 {
t.Error("tcp urgent", tcp.Urgent)
}
} else {
t.Error("Second header is not TCP header")
}
} else {
t.Error("First header is not IP header")
}
if string(p.Payload) != "GET / HTTP/1.1\r\nHost: www.fish.com\r\nConnection: keep-alive\r\nUser-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.121 Safari/535.2\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nAccept-Encoding: gzip,deflate,sdch\r\nAccept-Language: en-US,en;q=0.8\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3\r\n\r\n" {
t.Error("--- PAYLOAD STRING ---\n", string(p.Payload), "\n--- PAYLOAD BYTES ---\n", p.Payload)
}
}
// Makes sure packet payload doesn't display the 6 trailing null of this packet
// as part of the payload. They're actually the ethernet trailer.
func TestDecodeSmallTcpPacketHasEmptyPayload(t *testing.T) {
p := &Packet{
// This packet is only 54 bits (an empty TCP RST), thus 6 trailing null
// bytes are added by the ethernet layer to make it the minimum packet size.
Data: []byte{
0xbc, 0x30, 0x5b, 0xe8, 0xd3, 0x49, 0xb8, 0xac, 0x6f, 0x92, 0xd5, 0xbf,
0x08, 0x00, 0x45, 0x00, 0x00, 0x28, 0x00, 0x00, 0x40, 0x00, 0x40, 0x06,
0x3f, 0x9f, 0xac, 0x11, 0x51, 0xc5, 0xac, 0x11, 0x51, 0x49, 0x00, 0x63,
0x9a, 0xef, 0x00, 0x00, 0x00, 0x00, 0x2e, 0xc1, 0x27, 0x83, 0x50, 0x14,
0x00, 0x00, 0xc3, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}}
p.Decode()
if p.Payload == nil {
t.Error("Nil payload")
}
if len(p.Payload) != 0 {
t.Error("Non-empty payload:", p.Payload)
}
}
func TestDecodeVlanPacket(t *testing.T) {
p := &Packet{
Data: []byte{
0x00, 0x10, 0xdb, 0xff, 0x10, 0x00, 0x00, 0x15, 0x2c, 0x9d, 0xcc, 0x00, 0x81, 0x00, 0x01, 0xf7,
0x08, 0x00, 0x45, 0x00, 0x00, 0x28, 0x29, 0x8d, 0x40, 0x00, 0x7d, 0x06, 0x83, 0xa0, 0xac, 0x1b,
0xca, 0x8e, 0x45, 0x16, 0x94, 0xe2, 0xd4, 0x0a, 0x00, 0x50, 0xdf, 0xab, 0x9c, 0xc6, 0xcd, 0x1e,
0xe5, 0xd1, 0x50, 0x10, 0x01, 0x00, 0x5a, 0x74, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}}
p.Decode()
if p.Type != TYPE_VLAN {
t.Error("Didn't detect vlan")
}
if len(p.Headers) != 3 {
t.Error("Incorrect number of headers:", len(p.Headers))
for i, h := range p.Headers {
t.Errorf("Header %d: %#v", i, h)
}
t.FailNow()
}
if _, ok := p.Headers[0].(*Vlanhdr); !ok {
t.Errorf("First header isn't vlan: %q", p.Headers[0])
}
if _, ok := p.Headers[1].(*Iphdr); !ok {
t.Errorf("Second header isn't IP: %q", p.Headers[1])
}
if _, ok := p.Headers[2].(*Tcphdr); !ok {
t.Errorf("Third header isn't TCP: %q", p.Headers[2])
}
}
func TestDecodeFuzzFallout(t *testing.T) {
testData := []struct {
Data []byte
}{
{[]byte("000000000000\x81\x000")},
{[]byte("000000000000\x81\x00000")},
{[]byte("000000000000\x86\xdd0")},
{[]byte("000000000000\b\x000")},
{[]byte("000000000000\b\x060")},
{[]byte{}},
{[]byte("000000000000\b\x0600000000")},
{[]byte("000000000000\x86\xdd000000\x01000000000000000000000000000000000")},
{[]byte("000000000000\x81\x0000\b\x0600000000")},
{[]byte("000000000000\b\x00n0000000000000000000")},
{[]byte("000000000000\x86\xdd000000\x0100000000000000000000000000000000000")},
{[]byte("000000000000\x81\x0000\b\x00g0000000000000000000")},
//{[]byte()},
{[]byte("000000000000\b\x00400000000\x110000000000")},
{[]byte("0nMء\xfe\x13\x13\x81\x00gr\b\x00&x\xc9\xe5b'\x1e0\x00\x04\x00\x0020596224")},
{[]byte("000000000000\x81\x0000\b\x00400000000\x110000000000")},
{[]byte("000000000000\b\x00000000000\x0600\xff0000000")},
{[]byte("000000000000\x86\xdd000000\x06000000000000000000000000000000000")},
{[]byte("000000000000\x81\x0000\b\x00000000000\x0600b0000000")},
{[]byte("000000000000\x81\x0000\b\x00400000000\x060000000000")},
{[]byte("000000000000\x86\xdd000000\x11000000000000000000000000000000000")},
{[]byte("000000000000\x86\xdd000000\x0600000000000000000000000000000000000000000000M")},
{[]byte("000000000000\b\x00500000000\x0600000000000")},
{[]byte("0nM\xd80\xfe\x13\x13\x81\x00gr\b\x00&x\xc9\xe5b'\x1e0\x00\x04\x00\x0020596224")},
}
for _, entry := range testData {
pkt := &Packet{
Time: time.Now(),
Caplen: uint32(len(entry.Data)),
Len: uint32(len(entry.Data)),
Data: entry.Data,
}
pkt.Decode()
/*
func() {
defer func() {
if err := recover(); err != nil {
t.Fatalf("%d. %q failed: %v", idx, string(entry.Data), err)
}
}()
pkt.Decode()
}()
*/
}
}

View File

@ -1,206 +0,0 @@
package pcap
import (
"encoding/binary"
"fmt"
"io"
"time"
)
// FileHeader is the parsed header of a pcap file.
// http://wiki.wireshark.org/Development/LibpcapFileFormat
type FileHeader struct {
MagicNumber uint32
VersionMajor uint16
VersionMinor uint16
TimeZone int32
SigFigs uint32
SnapLen uint32
Network uint32
}
type PacketTime struct {
Sec int32
Usec int32
}
// Convert the PacketTime to a go Time struct.
func (p *PacketTime) Time() time.Time {
return time.Unix(int64(p.Sec), int64(p.Usec)*1000)
}
// Packet is a single packet parsed from a pcap file.
//
// Convenient access to IP, TCP, and UDP headers is provided after Decode()
// is called if the packet is of the appropriate type.
type Packet struct {
Time time.Time // packet send/receive time
Caplen uint32 // bytes stored in the file (caplen <= len)
Len uint32 // bytes sent/received
Data []byte // packet data
Type int // protocol type, see LINKTYPE_*
DestMac uint64
SrcMac uint64
Headers []interface{} // decoded headers, in order
Payload []byte // remaining non-header bytes
IP *Iphdr // IP header (for IP packets, after decoding)
TCP *Tcphdr // TCP header (for TCP packets, after decoding)
UDP *Udphdr // UDP header (for UDP packets after decoding)
}
// Reader parses pcap files.
type Reader struct {
flip bool
buf io.Reader
err error
fourBytes []byte
twoBytes []byte
sixteenBytes []byte
Header FileHeader
}
// NewReader reads pcap data from an io.Reader.
func NewReader(reader io.Reader) (*Reader, error) {
r := &Reader{
buf: reader,
fourBytes: make([]byte, 4),
twoBytes: make([]byte, 2),
sixteenBytes: make([]byte, 16),
}
switch magic := r.readUint32(); magic {
case 0xa1b2c3d4:
r.flip = false
case 0xd4c3b2a1:
r.flip = true
default:
return nil, fmt.Errorf("pcap: bad magic number: %0x", magic)
}
r.Header = FileHeader{
MagicNumber: 0xa1b2c3d4,
VersionMajor: r.readUint16(),
VersionMinor: r.readUint16(),
TimeZone: r.readInt32(),
SigFigs: r.readUint32(),
SnapLen: r.readUint32(),
Network: r.readUint32(),
}
return r, nil
}
// Next returns the next packet or nil if no more packets can be read.
func (r *Reader) Next() *Packet {
d := r.sixteenBytes
r.err = r.read(d)
if r.err != nil {
return nil
}
timeSec := asUint32(d[0:4], r.flip)
timeUsec := asUint32(d[4:8], r.flip)
capLen := asUint32(d[8:12], r.flip)
origLen := asUint32(d[12:16], r.flip)
data := make([]byte, capLen)
if r.err = r.read(data); r.err != nil {
return nil
}
return &Packet{
Time: time.Unix(int64(timeSec), int64(timeUsec)),
Caplen: capLen,
Len: origLen,
Data: data,
}
}
func (r *Reader) read(data []byte) error {
var err error
n, err := r.buf.Read(data)
for err == nil && n != len(data) {
var chunk int
chunk, err = r.buf.Read(data[n:])
n += chunk
}
if len(data) == n {
return nil
}
return err
}
func (r *Reader) readUint32() uint32 {
data := r.fourBytes
if r.err = r.read(data); r.err != nil {
return 0
}
return asUint32(data, r.flip)
}
func (r *Reader) readInt32() int32 {
data := r.fourBytes
if r.err = r.read(data); r.err != nil {
return 0
}
return int32(asUint32(data, r.flip))
}
func (r *Reader) readUint16() uint16 {
data := r.twoBytes
if r.err = r.read(data); r.err != nil {
return 0
}
return asUint16(data, r.flip)
}
// Writer writes a pcap file.
type Writer struct {
writer io.Writer
buf []byte
}
// NewWriter creates a Writer that stores output in an io.Writer.
// The FileHeader is written immediately.
func NewWriter(writer io.Writer, header *FileHeader) (*Writer, error) {
w := &Writer{
writer: writer,
buf: make([]byte, 24),
}
binary.LittleEndian.PutUint32(w.buf, header.MagicNumber)
binary.LittleEndian.PutUint16(w.buf[4:], header.VersionMajor)
binary.LittleEndian.PutUint16(w.buf[6:], header.VersionMinor)
binary.LittleEndian.PutUint32(w.buf[8:], uint32(header.TimeZone))
binary.LittleEndian.PutUint32(w.buf[12:], header.SigFigs)
binary.LittleEndian.PutUint32(w.buf[16:], header.SnapLen)
binary.LittleEndian.PutUint32(w.buf[20:], header.Network)
if _, err := writer.Write(w.buf); err != nil {
return nil, err
}
return w, nil
}
// Writer writes a packet to the underlying writer.
func (w *Writer) Write(pkt *Packet) error {
binary.LittleEndian.PutUint32(w.buf, uint32(pkt.Time.Unix()))
binary.LittleEndian.PutUint32(w.buf[4:], uint32(pkt.Time.Nanosecond()))
binary.LittleEndian.PutUint32(w.buf[8:], uint32(pkt.Time.Unix()))
binary.LittleEndian.PutUint32(w.buf[12:], pkt.Len)
if _, err := w.writer.Write(w.buf[:16]); err != nil {
return err
}
_, err := w.writer.Write(pkt.Data)
return err
}
func asUint32(data []byte, flip bool) uint32 {
if flip {
return binary.BigEndian.Uint32(data)
}
return binary.LittleEndian.Uint32(data)
}
func asUint16(data []byte, flip bool) uint16 {
if flip {
return binary.BigEndian.Uint16(data)
}
return binary.LittleEndian.Uint16(data)
}

View File

@ -1,266 +0,0 @@
// Interface to both live and offline pcap parsing.
package pcap
/*
#cgo linux LDFLAGS: -lpcap
#cgo freebsd LDFLAGS: -lpcap
#cgo darwin LDFLAGS: -lpcap
#cgo windows CFLAGS: -I C:/WpdPack/Include
#cgo windows,386 LDFLAGS: -L C:/WpdPack/Lib -lwpcap
#cgo windows,amd64 LDFLAGS: -L C:/WpdPack/Lib/x64 -lwpcap
#include <stdlib.h>
#include <pcap.h>
// Workaround for not knowing how to cast to const u_char**
int hack_pcap_next_ex(pcap_t *p, struct pcap_pkthdr **pkt_header,
u_char **pkt_data) {
return pcap_next_ex(p, pkt_header, (const u_char **)pkt_data);
}
*/
import "C"
import (
"errors"
"net"
"syscall"
"time"
"unsafe"
)
type Pcap struct {
cptr *C.pcap_t
}
type Stat struct {
PacketsReceived uint32
PacketsDropped uint32
PacketsIfDropped uint32
}
type Interface struct {
Name string
Description string
Addresses []IFAddress
// TODO: add more elements
}
type IFAddress struct {
IP net.IP
Netmask net.IPMask
// TODO: add broadcast + PtP dst ?
}
func (p *Pcap) Next() (pkt *Packet) {
rv, _ := p.NextEx()
return rv
}
// Openlive opens a device and returns a *Pcap handler
func Openlive(device string, snaplen int32, promisc bool, timeout_ms int32) (handle *Pcap, err error) {
var buf *C.char
buf = (*C.char)(C.calloc(ERRBUF_SIZE, 1))
h := new(Pcap)
var pro int32
if promisc {
pro = 1
}
dev := C.CString(device)
defer C.free(unsafe.Pointer(dev))
h.cptr = C.pcap_open_live(dev, C.int(snaplen), C.int(pro), C.int(timeout_ms), buf)
if nil == h.cptr {
handle = nil
err = errors.New(C.GoString(buf))
} else {
handle = h
}
C.free(unsafe.Pointer(buf))
return
}
func Openoffline(file string) (handle *Pcap, err error) {
var buf *C.char
buf = (*C.char)(C.calloc(ERRBUF_SIZE, 1))
h := new(Pcap)
cf := C.CString(file)
defer C.free(unsafe.Pointer(cf))
h.cptr = C.pcap_open_offline(cf, buf)
if nil == h.cptr {
handle = nil
err = errors.New(C.GoString(buf))
} else {
handle = h
}
C.free(unsafe.Pointer(buf))
return
}
func (p *Pcap) NextEx() (pkt *Packet, result int32) {
var pkthdr *C.struct_pcap_pkthdr
var buf_ptr *C.u_char
var buf unsafe.Pointer
result = int32(C.hack_pcap_next_ex(p.cptr, &pkthdr, &buf_ptr))
buf = unsafe.Pointer(buf_ptr)
if nil == buf {
return
}
pkt = new(Packet)
pkt.Time = time.Unix(int64(pkthdr.ts.tv_sec), int64(pkthdr.ts.tv_usec)*1000)
pkt.Caplen = uint32(pkthdr.caplen)
pkt.Len = uint32(pkthdr.len)
pkt.Data = C.GoBytes(buf, C.int(pkthdr.caplen))
return
}
func (p *Pcap) Close() {
C.pcap_close(p.cptr)
}
func (p *Pcap) Geterror() error {
return errors.New(C.GoString(C.pcap_geterr(p.cptr)))
}
func (p *Pcap) Getstats() (stat *Stat, err error) {
var cstats _Ctype_struct_pcap_stat
if -1 == C.pcap_stats(p.cptr, &cstats) {
return nil, p.Geterror()
}
stats := new(Stat)
stats.PacketsReceived = uint32(cstats.ps_recv)
stats.PacketsDropped = uint32(cstats.ps_drop)
stats.PacketsIfDropped = uint32(cstats.ps_ifdrop)
return stats, nil
}
func (p *Pcap) Setfilter(expr string) (err error) {
var bpf _Ctype_struct_bpf_program
cexpr := C.CString(expr)
defer C.free(unsafe.Pointer(cexpr))
if -1 == C.pcap_compile(p.cptr, &bpf, cexpr, 1, 0) {
return p.Geterror()
}
if -1 == C.pcap_setfilter(p.cptr, &bpf) {
C.pcap_freecode(&bpf)
return p.Geterror()
}
C.pcap_freecode(&bpf)
return nil
}
func Version() string {
return C.GoString(C.pcap_lib_version())
}
func (p *Pcap) Datalink() int {
return int(C.pcap_datalink(p.cptr))
}
func (p *Pcap) Setdatalink(dlt int) error {
if -1 == C.pcap_set_datalink(p.cptr, C.int(dlt)) {
return p.Geterror()
}
return nil
}
func DatalinkValueToName(dlt int) string {
if name := C.pcap_datalink_val_to_name(C.int(dlt)); name != nil {
return C.GoString(name)
}
return ""
}
func DatalinkValueToDescription(dlt int) string {
if desc := C.pcap_datalink_val_to_description(C.int(dlt)); desc != nil {
return C.GoString(desc)
}
return ""
}
func Findalldevs() (ifs []Interface, err error) {
var buf *C.char
buf = (*C.char)(C.calloc(ERRBUF_SIZE, 1))
defer C.free(unsafe.Pointer(buf))
var alldevsp *C.pcap_if_t
if -1 == C.pcap_findalldevs((**C.pcap_if_t)(&alldevsp), buf) {
return nil, errors.New(C.GoString(buf))
}
defer C.pcap_freealldevs((*C.pcap_if_t)(alldevsp))
dev := alldevsp
var i uint32
for i = 0; dev != nil; dev = (*C.pcap_if_t)(dev.next) {
i++
}
ifs = make([]Interface, i)
dev = alldevsp
for j := uint32(0); dev != nil; dev = (*C.pcap_if_t)(dev.next) {
var iface Interface
iface.Name = C.GoString(dev.name)
iface.Description = C.GoString(dev.description)
iface.Addresses = findalladdresses(dev.addresses)
// TODO: add more elements
ifs[j] = iface
j++
}
return
}
func findalladdresses(addresses *_Ctype_struct_pcap_addr) (retval []IFAddress) {
// TODO - make it support more than IPv4 and IPv6?
retval = make([]IFAddress, 0, 1)
for curaddr := addresses; curaddr != nil; curaddr = (*_Ctype_struct_pcap_addr)(curaddr.next) {
var a IFAddress
var err error
if a.IP, err = sockaddr_to_IP((*syscall.RawSockaddr)(unsafe.Pointer(curaddr.addr))); err != nil {
continue
}
if a.Netmask, err = sockaddr_to_IP((*syscall.RawSockaddr)(unsafe.Pointer(curaddr.addr))); err != nil {
continue
}
retval = append(retval, a)
}
return
}
func sockaddr_to_IP(rsa *syscall.RawSockaddr) (IP []byte, err error) {
switch rsa.Family {
case syscall.AF_INET:
pp := (*syscall.RawSockaddrInet4)(unsafe.Pointer(rsa))
IP = make([]byte, 4)
for i := 0; i < len(IP); i++ {
IP[i] = pp.Addr[i]
}
return
case syscall.AF_INET6:
pp := (*syscall.RawSockaddrInet6)(unsafe.Pointer(rsa))
IP = make([]byte, 16)
for i := 0; i < len(IP); i++ {
IP[i] = pp.Addr[i]
}
return
}
err = errors.New("Unsupported address type")
return
}
func (p *Pcap) Inject(data []byte) (err error) {
buf := (*C.char)(C.malloc((C.size_t)(len(data))))
for i := 0; i < len(data); i++ {
*(*byte)(unsafe.Pointer(uintptr(unsafe.Pointer(buf)) + uintptr(i))) = data[i]
}
if -1 == C.pcap_sendpacket(p.cptr, (*C.u_char)(unsafe.Pointer(buf)), (C.int)(len(data))) {
err = p.Geterror()
}
C.free(unsafe.Pointer(buf))
return
}

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@ -1,49 +0,0 @@
package main
import (
"flag"
"fmt"
"os"
"runtime/pprof"
"time"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/akrennmair/gopcap"
)
func main() {
var filename *string = flag.String("file", "", "filename")
var decode *bool = flag.Bool("d", false, "If true, decode each packet")
var cpuprofile *string = flag.String("cpuprofile", "", "filename")
flag.Parse()
h, err := pcap.Openoffline(*filename)
if err != nil {
fmt.Printf("Couldn't create pcap reader: %v", err)
}
if *cpuprofile != "" {
if out, err := os.Create(*cpuprofile); err == nil {
pprof.StartCPUProfile(out)
defer func() {
pprof.StopCPUProfile()
out.Close()
}()
} else {
panic(err)
}
}
i, nilPackets := 0, 0
start := time.Now()
for pkt, code := h.NextEx(); code != -2; pkt, code = h.NextEx() {
if pkt == nil {
nilPackets++
} else if *decode {
pkt.Decode()
}
i++
}
duration := time.Since(start)
fmt.Printf("Took %v to process %v packets, %v per packet, %d nil packets\n", duration, i, duration/time.Duration(i), nilPackets)
}

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@ -1,96 +0,0 @@
package main
// Parses a pcap file, writes it back to disk, then verifies the files
// are the same.
import (
"bufio"
"flag"
"fmt"
"io"
"os"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/akrennmair/gopcap"
)
var input *string = flag.String("input", "", "input file")
var output *string = flag.String("output", "", "output file")
var decode *bool = flag.Bool("decode", false, "print decoded packets")
func copyPcap(dest, src string) {
f, err := os.Open(src)
if err != nil {
fmt.Printf("couldn't open %q: %v\n", src, err)
return
}
defer f.Close()
reader, err := pcap.NewReader(bufio.NewReader(f))
if err != nil {
fmt.Printf("couldn't create reader: %v\n", err)
return
}
w, err := os.Create(dest)
if err != nil {
fmt.Printf("couldn't open %q: %v\n", dest, err)
return
}
defer w.Close()
buf := bufio.NewWriter(w)
writer, err := pcap.NewWriter(buf, &reader.Header)
if err != nil {
fmt.Printf("couldn't create writer: %v\n", err)
return
}
for {
pkt := reader.Next()
if pkt == nil {
break
}
if *decode {
pkt.Decode()
fmt.Println(pkt.String())
}
writer.Write(pkt)
}
buf.Flush()
}
func check(dest, src string) {
f, err := os.Open(src)
if err != nil {
fmt.Printf("couldn't open %q: %v\n", src, err)
return
}
defer f.Close()
freader := bufio.NewReader(f)
g, err := os.Open(dest)
if err != nil {
fmt.Printf("couldn't open %q: %v\n", src, err)
return
}
defer g.Close()
greader := bufio.NewReader(g)
for {
fb, ferr := freader.ReadByte()
gb, gerr := greader.ReadByte()
if ferr == io.EOF && gerr == io.EOF {
break
}
if fb == gb {
continue
}
fmt.Println("FAIL")
return
}
fmt.Println("PASS")
}
func main() {
flag.Parse()
copyPcap(*output, *input)
check(*output, *input)
}

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@ -1,82 +0,0 @@
package main
import (
"flag"
"fmt"
"time"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/akrennmair/gopcap"
)
func min(x uint32, y uint32) uint32 {
if x < y {
return x
}
return y
}
func main() {
var device *string = flag.String("d", "", "device")
var file *string = flag.String("r", "", "file")
var expr *string = flag.String("e", "", "filter expression")
flag.Parse()
var h *pcap.Pcap
var err error
ifs, err := pcap.Findalldevs()
if len(ifs) == 0 {
fmt.Printf("Warning: no devices found : %s\n", err)
} else {
for i := 0; i < len(ifs); i++ {
fmt.Printf("dev %d: %s (%s)\n", i+1, ifs[i].Name, ifs[i].Description)
}
}
if *device != "" {
h, err = pcap.Openlive(*device, 65535, true, 0)
if h == nil {
fmt.Printf("Openlive(%s) failed: %s\n", *device, err)
return
}
} else if *file != "" {
h, err = pcap.Openoffline(*file)
if h == nil {
fmt.Printf("Openoffline(%s) failed: %s\n", *file, err)
return
}
} else {
fmt.Printf("usage: pcaptest [-d <device> | -r <file>]\n")
return
}
defer h.Close()
fmt.Printf("pcap version: %s\n", pcap.Version())
if *expr != "" {
fmt.Printf("Setting filter: %s\n", *expr)
err := h.Setfilter(*expr)
if err != nil {
fmt.Printf("Warning: setting filter failed: %s\n", err)
}
}
for pkt := h.Next(); pkt != nil; pkt = h.Next() {
fmt.Printf("time: %d.%06d (%s) caplen: %d len: %d\nData:",
int64(pkt.Time.Second()), int64(pkt.Time.Nanosecond()),
time.Unix(int64(pkt.Time.Second()), 0).String(), int64(pkt.Caplen), int64(pkt.Len))
for i := uint32(0); i < pkt.Caplen; i++ {
if i%32 == 0 {
fmt.Printf("\n")
}
if 32 <= pkt.Data[i] && pkt.Data[i] <= 126 {
fmt.Printf("%c", pkt.Data[i])
} else {
fmt.Printf(".")
}
}
fmt.Printf("\n\n")
}
}

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@ -1,121 +0,0 @@
package main
import (
"bufio"
"flag"
"fmt"
"os"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/akrennmair/gopcap"
)
const (
TYPE_IP = 0x0800
TYPE_ARP = 0x0806
TYPE_IP6 = 0x86DD
IP_ICMP = 1
IP_INIP = 4
IP_TCP = 6
IP_UDP = 17
)
var out *bufio.Writer
var errout *bufio.Writer
func main() {
var device *string = flag.String("i", "", "interface")
var snaplen *int = flag.Int("s", 65535, "snaplen")
var hexdump *bool = flag.Bool("X", false, "hexdump")
expr := ""
out = bufio.NewWriter(os.Stdout)
errout = bufio.NewWriter(os.Stderr)
flag.Usage = func() {
fmt.Fprintf(errout, "usage: %s [ -i interface ] [ -s snaplen ] [ -X ] [ expression ]\n", os.Args[0])
errout.Flush()
os.Exit(1)
}
flag.Parse()
if len(flag.Args()) > 0 {
expr = flag.Arg(0)
}
if *device == "" {
devs, err := pcap.Findalldevs()
if err != nil {
fmt.Fprintf(errout, "tcpdump: couldn't find any devices: %s\n", err)
}
if 0 == len(devs) {
flag.Usage()
}
*device = devs[0].Name
}
h, err := pcap.Openlive(*device, int32(*snaplen), true, 0)
if h == nil {
fmt.Fprintf(errout, "tcpdump: %s\n", err)
errout.Flush()
return
}
defer h.Close()
if expr != "" {
ferr := h.Setfilter(expr)
if ferr != nil {
fmt.Fprintf(out, "tcpdump: %s\n", ferr)
out.Flush()
}
}
for pkt := h.Next(); pkt != nil; pkt = h.Next() {
pkt.Decode()
fmt.Fprintf(out, "%s\n", pkt.String())
if *hexdump {
Hexdump(pkt)
}
out.Flush()
}
}
func min(a, b int) int {
if a < b {
return a
}
return b
}
func Hexdump(pkt *pcap.Packet) {
for i := 0; i < len(pkt.Data); i += 16 {
Dumpline(uint32(i), pkt.Data[i:min(i+16, len(pkt.Data))])
}
}
func Dumpline(addr uint32, line []byte) {
fmt.Fprintf(out, "\t0x%04x: ", int32(addr))
var i uint16
for i = 0; i < 16 && i < uint16(len(line)); i++ {
if i%2 == 0 {
out.WriteString(" ")
}
fmt.Fprintf(out, "%02x", line[i])
}
for j := i; j <= 16; j++ {
if j%2 == 0 {
out.WriteString(" ")
}
out.WriteString(" ")
}
out.WriteString(" ")
for i = 0; i < 16 && i < uint16(len(line)); i++ {
if line[i] >= 32 && line[i] <= 126 {
fmt.Fprintf(out, "%c", line[i])
} else {
out.WriteString(".")
}
}
out.WriteString("\n")
}

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@ -1,63 +0,0 @@
package quantile
import (
"testing"
)
func BenchmarkInsertTargeted(b *testing.B) {
b.ReportAllocs()
s := NewTargeted(Targets)
b.ResetTimer()
for i := float64(0); i < float64(b.N); i++ {
s.Insert(i)
}
}
func BenchmarkInsertTargetedSmallEpsilon(b *testing.B) {
s := NewTargeted(TargetsSmallEpsilon)
b.ResetTimer()
for i := float64(0); i < float64(b.N); i++ {
s.Insert(i)
}
}
func BenchmarkInsertBiased(b *testing.B) {
s := NewLowBiased(0.01)
b.ResetTimer()
for i := float64(0); i < float64(b.N); i++ {
s.Insert(i)
}
}
func BenchmarkInsertBiasedSmallEpsilon(b *testing.B) {
s := NewLowBiased(0.0001)
b.ResetTimer()
for i := float64(0); i < float64(b.N); i++ {
s.Insert(i)
}
}
func BenchmarkQuery(b *testing.B) {
s := NewTargeted(Targets)
for i := float64(0); i < 1e6; i++ {
s.Insert(i)
}
b.ResetTimer()
n := float64(b.N)
for i := float64(0); i < n; i++ {
s.Query(i / n)
}
}
func BenchmarkQuerySmallEpsilon(b *testing.B) {
s := NewTargeted(TargetsSmallEpsilon)
for i := float64(0); i < 1e6; i++ {
s.Insert(i)
}
b.ResetTimer()
n := float64(b.N)
for i := float64(0); i < n; i++ {
s.Query(i / n)
}
}

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@ -1,121 +0,0 @@
// +build go1.1
package quantile_test
import (
"bufio"
"fmt"
"log"
"os"
"strconv"
"time"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/beorn7/perks/quantile"
)
func Example_simple() {
ch := make(chan float64)
go sendFloats(ch)
// Compute the 50th, 90th, and 99th percentile.
q := quantile.NewTargeted(map[float64]float64{
0.50: 0.005,
0.90: 0.001,
0.99: 0.0001,
})
for v := range ch {
q.Insert(v)
}
fmt.Println("perc50:", q.Query(0.50))
fmt.Println("perc90:", q.Query(0.90))
fmt.Println("perc99:", q.Query(0.99))
fmt.Println("count:", q.Count())
// Output:
// perc50: 5
// perc90: 16
// perc99: 223
// count: 2388
}
func Example_mergeMultipleStreams() {
// Scenario:
// We have multiple database shards. On each shard, there is a process
// collecting query response times from the database logs and inserting
// them into a Stream (created via NewTargeted(0.90)), much like the
// Simple example. These processes expose a network interface for us to
// ask them to serialize and send us the results of their
// Stream.Samples so we may Merge and Query them.
//
// NOTES:
// * These sample sets are small, allowing us to get them
// across the network much faster than sending the entire list of data
// points.
//
// * For this to work correctly, we must supply the same quantiles
// a priori the process collecting the samples supplied to NewTargeted,
// even if we do not plan to query them all here.
ch := make(chan quantile.Samples)
getDBQuerySamples(ch)
q := quantile.NewTargeted(map[float64]float64{0.90: 0.001})
for samples := range ch {
q.Merge(samples)
}
fmt.Println("perc90:", q.Query(0.90))
}
func Example_window() {
// Scenario: We want the 90th, 95th, and 99th percentiles for each
// minute.
ch := make(chan float64)
go sendStreamValues(ch)
tick := time.NewTicker(1 * time.Minute)
q := quantile.NewTargeted(map[float64]float64{
0.90: 0.001,
0.95: 0.0005,
0.99: 0.0001,
})
for {
select {
case t := <-tick.C:
flushToDB(t, q.Samples())
q.Reset()
case v := <-ch:
q.Insert(v)
}
}
}
func sendStreamValues(ch chan float64) {
// Use your imagination
}
func flushToDB(t time.Time, samples quantile.Samples) {
// Use your imagination
}
// This is a stub for the above example. In reality this would hit the remote
// servers via http or something like it.
func getDBQuerySamples(ch chan quantile.Samples) {}
func sendFloats(ch chan<- float64) {
f, err := os.Open("exampledata.txt")
if err != nil {
log.Fatal(err)
}
sc := bufio.NewScanner(f)
for sc.Scan() {
b := sc.Bytes()
v, err := strconv.ParseFloat(string(b), 64)
if err != nil {
log.Fatal(err)
}
ch <- v
}
if sc.Err() != nil {
log.Fatal(sc.Err())
}
close(ch)
}

File diff suppressed because it is too large Load Diff

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@ -1,292 +0,0 @@
// Package quantile computes approximate quantiles over an unbounded data
// stream within low memory and CPU bounds.
//
// A small amount of accuracy is traded to achieve the above properties.
//
// Multiple streams can be merged before calling Query to generate a single set
// of results. This is meaningful when the streams represent the same type of
// data. See Merge and Samples.
//
// For more detailed information about the algorithm used, see:
//
// Effective Computation of Biased Quantiles over Data Streams
//
// http://www.cs.rutgers.edu/~muthu/bquant.pdf
package quantile
import (
"math"
"sort"
)
// Sample holds an observed value and meta information for compression. JSON
// tags have been added for convenience.
type Sample struct {
Value float64 `json:",string"`
Width float64 `json:",string"`
Delta float64 `json:",string"`
}
// Samples represents a slice of samples. It implements sort.Interface.
type Samples []Sample
func (a Samples) Len() int { return len(a) }
func (a Samples) Less(i, j int) bool { return a[i].Value < a[j].Value }
func (a Samples) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
type invariant func(s *stream, r float64) float64
// NewLowBiased returns an initialized Stream for low-biased quantiles
// (e.g. 0.01, 0.1, 0.5) where the needed quantiles are not known a priori, but
// error guarantees can still be given even for the lower ranks of the data
// distribution.
//
// The provided epsilon is a relative error, i.e. the true quantile of a value
// returned by a query is guaranteed to be within (1±Epsilon)*Quantile.
//
// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error
// properties.
func NewLowBiased(epsilon float64) *Stream {
ƒ := func(s *stream, r float64) float64 {
return 2 * epsilon * r
}
return newStream(ƒ)
}
// NewHighBiased returns an initialized Stream for high-biased quantiles
// (e.g. 0.01, 0.1, 0.5) where the needed quantiles are not known a priori, but
// error guarantees can still be given even for the higher ranks of the data
// distribution.
//
// The provided epsilon is a relative error, i.e. the true quantile of a value
// returned by a query is guaranteed to be within 1-(1±Epsilon)*(1-Quantile).
//
// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error
// properties.
func NewHighBiased(epsilon float64) *Stream {
ƒ := func(s *stream, r float64) float64 {
return 2 * epsilon * (s.n - r)
}
return newStream(ƒ)
}
// NewTargeted returns an initialized Stream concerned with a particular set of
// quantile values that are supplied a priori. Knowing these a priori reduces
// space and computation time. The targets map maps the desired quantiles to
// their absolute errors, i.e. the true quantile of a value returned by a query
// is guaranteed to be within (Quantile±Epsilon).
//
// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error properties.
func NewTargeted(targets map[float64]float64) *Stream {
ƒ := func(s *stream, r float64) float64 {
var m = math.MaxFloat64
var f float64
for quantile, epsilon := range targets {
if quantile*s.n <= r {
f = (2 * epsilon * r) / quantile
} else {
f = (2 * epsilon * (s.n - r)) / (1 - quantile)
}
if f < m {
m = f
}
}
return m
}
return newStream(ƒ)
}
// Stream computes quantiles for a stream of float64s. It is not thread-safe by
// design. Take care when using across multiple goroutines.
type Stream struct {
*stream
b Samples
sorted bool
}
func newStream(ƒ invariant) *Stream {
x := &stream{ƒ: ƒ}
return &Stream{x, make(Samples, 0, 500), true}
}
// Insert inserts v into the stream.
func (s *Stream) Insert(v float64) {
s.insert(Sample{Value: v, Width: 1})
}
func (s *Stream) insert(sample Sample) {
s.b = append(s.b, sample)
s.sorted = false
if len(s.b) == cap(s.b) {
s.flush()
}
}
// Query returns the computed qth percentiles value. If s was created with
// NewTargeted, and q is not in the set of quantiles provided a priori, Query
// will return an unspecified result.
func (s *Stream) Query(q float64) float64 {
if !s.flushed() {
// Fast path when there hasn't been enough data for a flush;
// this also yields better accuracy for small sets of data.
l := len(s.b)
if l == 0 {
return 0
}
i := int(float64(l) * q)
if i > 0 {
i -= 1
}
s.maybeSort()
return s.b[i].Value
}
s.flush()
return s.stream.query(q)
}
// Merge merges samples into the underlying streams samples. This is handy when
// merging multiple streams from separate threads, database shards, etc.
//
// ATTENTION: This method is broken and does not yield correct results. The
// underlying algorithm is not capable of merging streams correctly.
func (s *Stream) Merge(samples Samples) {
sort.Sort(samples)
s.stream.merge(samples)
}
// Reset reinitializes and clears the list reusing the samples buffer memory.
func (s *Stream) Reset() {
s.stream.reset()
s.b = s.b[:0]
}
// Samples returns stream samples held by s.
func (s *Stream) Samples() Samples {
if !s.flushed() {
return s.b
}
s.flush()
return s.stream.samples()
}
// Count returns the total number of samples observed in the stream
// since initialization.
func (s *Stream) Count() int {
return len(s.b) + s.stream.count()
}
func (s *Stream) flush() {
s.maybeSort()
s.stream.merge(s.b)
s.b = s.b[:0]
}
func (s *Stream) maybeSort() {
if !s.sorted {
s.sorted = true
sort.Sort(s.b)
}
}
func (s *Stream) flushed() bool {
return len(s.stream.l) > 0
}
type stream struct {
n float64
l []Sample
ƒ invariant
}
func (s *stream) reset() {
s.l = s.l[:0]
s.n = 0
}
func (s *stream) insert(v float64) {
s.merge(Samples{{v, 1, 0}})
}
func (s *stream) merge(samples Samples) {
// TODO(beorn7): This tries to merge not only individual samples, but
// whole summaries. The paper doesn't mention merging summaries at
// all. Unittests show that the merging is inaccurate. Find out how to
// do merges properly.
var r float64
i := 0
for _, sample := range samples {
for ; i < len(s.l); i++ {
c := s.l[i]
if c.Value > sample.Value {
// Insert at position i.
s.l = append(s.l, Sample{})
copy(s.l[i+1:], s.l[i:])
s.l[i] = Sample{
sample.Value,
sample.Width,
math.Max(sample.Delta, math.Floor(s.ƒ(s, r))-1),
// TODO(beorn7): How to calculate delta correctly?
}
i++
goto inserted
}
r += c.Width
}
s.l = append(s.l, Sample{sample.Value, sample.Width, 0})
i++
inserted:
s.n += sample.Width
r += sample.Width
}
s.compress()
}
func (s *stream) count() int {
return int(s.n)
}
func (s *stream) query(q float64) float64 {
t := math.Ceil(q * s.n)
t += math.Ceil(s.ƒ(s, t) / 2)
p := s.l[0]
var r float64
for _, c := range s.l[1:] {
r += p.Width
if r+c.Width+c.Delta > t {
return p.Value
}
p = c
}
return p.Value
}
func (s *stream) compress() {
if len(s.l) < 2 {
return
}
x := s.l[len(s.l)-1]
xi := len(s.l) - 1
r := s.n - 1 - x.Width
for i := len(s.l) - 2; i >= 0; i-- {
c := s.l[i]
if c.Width+x.Width+x.Delta <= s.ƒ(s, r) {
x.Width += c.Width
s.l[xi] = x
// Remove element at i.
copy(s.l[i:], s.l[i+1:])
s.l = s.l[:len(s.l)-1]
xi -= 1
} else {
x = c
xi = i
}
r -= c.Width
}
}
func (s *stream) samples() Samples {
samples := make(Samples, len(s.l))
copy(samples, s.l)
return samples
}

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@ -1,188 +0,0 @@
package quantile
import (
"math"
"math/rand"
"sort"
"testing"
)
var (
Targets = map[float64]float64{
0.01: 0.001,
0.10: 0.01,
0.50: 0.05,
0.90: 0.01,
0.99: 0.001,
}
TargetsSmallEpsilon = map[float64]float64{
0.01: 0.0001,
0.10: 0.001,
0.50: 0.005,
0.90: 0.001,
0.99: 0.0001,
}
LowQuantiles = []float64{0.01, 0.1, 0.5}
HighQuantiles = []float64{0.99, 0.9, 0.5}
)
const RelativeEpsilon = 0.01
func verifyPercsWithAbsoluteEpsilon(t *testing.T, a []float64, s *Stream) {
sort.Float64s(a)
for quantile, epsilon := range Targets {
n := float64(len(a))
k := int(quantile * n)
lower := int((quantile - epsilon) * n)
if lower < 1 {
lower = 1
}
upper := int(math.Ceil((quantile + epsilon) * n))
if upper > len(a) {
upper = len(a)
}
w, min, max := a[k-1], a[lower-1], a[upper-1]
if g := s.Query(quantile); g < min || g > max {
t.Errorf("q=%f: want %v [%f,%f], got %v", quantile, w, min, max, g)
}
}
}
func verifyLowPercsWithRelativeEpsilon(t *testing.T, a []float64, s *Stream) {
sort.Float64s(a)
for _, qu := range LowQuantiles {
n := float64(len(a))
k := int(qu * n)
lowerRank := int((1 - RelativeEpsilon) * qu * n)
upperRank := int(math.Ceil((1 + RelativeEpsilon) * qu * n))
w, min, max := a[k-1], a[lowerRank-1], a[upperRank-1]
if g := s.Query(qu); g < min || g > max {
t.Errorf("q=%f: want %v [%f,%f], got %v", qu, w, min, max, g)
}
}
}
func verifyHighPercsWithRelativeEpsilon(t *testing.T, a []float64, s *Stream) {
sort.Float64s(a)
for _, qu := range HighQuantiles {
n := float64(len(a))
k := int(qu * n)
lowerRank := int((1 - (1+RelativeEpsilon)*(1-qu)) * n)
upperRank := int(math.Ceil((1 - (1-RelativeEpsilon)*(1-qu)) * n))
w, min, max := a[k-1], a[lowerRank-1], a[upperRank-1]
if g := s.Query(qu); g < min || g > max {
t.Errorf("q=%f: want %v [%f,%f], got %v", qu, w, min, max, g)
}
}
}
func populateStream(s *Stream) []float64 {
a := make([]float64, 0, 1e5+100)
for i := 0; i < cap(a); i++ {
v := rand.NormFloat64()
// Add 5% asymmetric outliers.
if i%20 == 0 {
v = v*v + 1
}
s.Insert(v)
a = append(a, v)
}
return a
}
func TestTargetedQuery(t *testing.T) {
rand.Seed(42)
s := NewTargeted(Targets)
a := populateStream(s)
verifyPercsWithAbsoluteEpsilon(t, a, s)
}
func TestLowBiasedQuery(t *testing.T) {
rand.Seed(42)
s := NewLowBiased(RelativeEpsilon)
a := populateStream(s)
verifyLowPercsWithRelativeEpsilon(t, a, s)
}
func TestHighBiasedQuery(t *testing.T) {
rand.Seed(42)
s := NewHighBiased(RelativeEpsilon)
a := populateStream(s)
verifyHighPercsWithRelativeEpsilon(t, a, s)
}
// BrokenTestTargetedMerge is broken, see Merge doc comment.
func BrokenTestTargetedMerge(t *testing.T) {
rand.Seed(42)
s1 := NewTargeted(Targets)
s2 := NewTargeted(Targets)
a := populateStream(s1)
a = append(a, populateStream(s2)...)
s1.Merge(s2.Samples())
verifyPercsWithAbsoluteEpsilon(t, a, s1)
}
// BrokenTestLowBiasedMerge is broken, see Merge doc comment.
func BrokenTestLowBiasedMerge(t *testing.T) {
rand.Seed(42)
s1 := NewLowBiased(RelativeEpsilon)
s2 := NewLowBiased(RelativeEpsilon)
a := populateStream(s1)
a = append(a, populateStream(s2)...)
s1.Merge(s2.Samples())
verifyLowPercsWithRelativeEpsilon(t, a, s2)
}
// BrokenTestHighBiasedMerge is broken, see Merge doc comment.
func BrokenTestHighBiasedMerge(t *testing.T) {
rand.Seed(42)
s1 := NewHighBiased(RelativeEpsilon)
s2 := NewHighBiased(RelativeEpsilon)
a := populateStream(s1)
a = append(a, populateStream(s2)...)
s1.Merge(s2.Samples())
verifyHighPercsWithRelativeEpsilon(t, a, s2)
}
func TestUncompressed(t *testing.T) {
q := NewTargeted(Targets)
for i := 100; i > 0; i-- {
q.Insert(float64(i))
}
if g := q.Count(); g != 100 {
t.Errorf("want count 100, got %d", g)
}
// Before compression, Query should have 100% accuracy.
for quantile := range Targets {
w := quantile * 100
if g := q.Query(quantile); g != w {
t.Errorf("want %f, got %f", w, g)
}
}
}
func TestUncompressedSamples(t *testing.T) {
q := NewTargeted(map[float64]float64{0.99: 0.001})
for i := 1; i <= 100; i++ {
q.Insert(float64(i))
}
if g := q.Samples().Len(); g != 100 {
t.Errorf("want count 100, got %d", g)
}
}
func TestUncompressedOne(t *testing.T) {
q := NewTargeted(map[float64]float64{0.99: 0.01})
q.Insert(3.14)
if g := q.Query(0.90); g != 3.14 {
t.Error("want PI, got", g)
}
}
func TestDefaults(t *testing.T) {
if g := NewTargeted(map[float64]float64{0.99: 0.001}).Query(0.99); g != 0 {
t.Errorf("want 0, got %f", g)
}
}

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@ -1,2 +0,0 @@
example/example
example/example.exe

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@ -1,201 +0,0 @@
Apache License
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http://www.apache.org/licenses/
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the terms of any separate license agreement you may have executed
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7. Disclaimer of Warranty. Unless required by applicable law or
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unless required by applicable law (such as deliberate and grossly
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on Your own behalf and on Your sole responsibility, not on behalf
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APPENDIX: How to apply the Apache License to your work.
To apply the Apache License to your work, attach the following
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
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Copyright [2013] [the CloudFoundry Authors]
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
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Unless required by applicable law or agreed to in writing, software
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

View File

@ -1,30 +0,0 @@
# Speakeasy
This package provides cross-platform Go (#golang) helpers for taking user input
from the terminal while not echoing the input back (similar to `getpasswd`). The
package uses syscalls to avoid any dependence on cgo, and is therefore
compatible with cross-compiling.
[![GoDoc](https://godoc.org/github.com/bgentry/speakeasy?status.png)][godoc]
## Unicode
Multi-byte unicode characters work successfully on Mac OS X. On Windows,
however, this may be problematic (as is UTF in general on Windows). Other
platforms have not been tested.
## License
The code herein was not written by me, but was compiled from two separate open
source packages. Unix portions were imported from [gopass][gopass], while
Windows portions were imported from the [CloudFoundry Go CLI][cf-cli]'s
[Windows terminal helpers][cf-ui-windows].
The [license for the windows portion](./LICENSE_WINDOWS) has been copied exactly
from the source (though I attempted to fill in the correct owner in the
boilerplate copyright notice).
[cf-cli]: https://github.com/cloudfoundry/cli "CloudFoundry Go CLI"
[cf-ui-windows]: https://github.com/cloudfoundry/cli/blob/master/src/cf/terminal/ui_windows.go "CloudFoundry Go CLI Windows input helpers"
[godoc]: https://godoc.org/github.com/bgentry/speakeasy "speakeasy on Godoc.org"
[gopass]: https://code.google.com/p/gopass "gopass"

View File

@ -1,18 +0,0 @@
package main
import (
"fmt"
"os"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/bgentry/speakeasy"
)
func main() {
password, err := speakeasy.Ask("Please enter a password: ")
if err != nil {
fmt.Println(err)
os.Exit(1)
}
fmt.Printf("Password result: %q\n", password)
fmt.Printf("Password len: %d\n", len(password))
}

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@ -1,47 +0,0 @@
package speakeasy
import (
"fmt"
"io"
"os"
"strings"
)
// Ask the user to enter a password with input hidden. prompt is a string to
// display before the user's input. Returns the provided password, or an error
// if the command failed.
func Ask(prompt string) (password string, err error) {
return FAsk(os.Stdout, prompt)
}
// Same as the Ask function, except it is possible to specify the file to write
// the prompt to.
func FAsk(file *os.File, prompt string) (password string, err error) {
if prompt != "" {
fmt.Fprint(file, prompt) // Display the prompt.
}
password, err = getPassword()
// Carriage return after the user input.
fmt.Fprintln(file, "")
return
}
func readline() (value string, err error) {
var valb []byte
var n int
b := make([]byte, 1)
for {
// read one byte at a time so we don't accidentally read extra bytes
n, err = os.Stdin.Read(b)
if err != nil && err != io.EOF {
return "", err
}
if n == 0 || b[0] == '\n' {
break
}
valb = append(valb, b[0])
}
return strings.TrimSuffix(string(valb), "\r"), nil
}

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@ -1,93 +0,0 @@
// based on https://code.google.com/p/gopass
// Author: johnsiilver@gmail.com (John Doak)
//
// Original code is based on code by RogerV in the golang-nuts thread:
// https://groups.google.com/group/golang-nuts/browse_thread/thread/40cc41e9d9fc9247
// +build darwin freebsd linux netbsd openbsd solaris
package speakeasy
import (
"fmt"
"os"
"os/signal"
"strings"
"syscall"
)
const sttyArg0 = "/bin/stty"
var (
sttyArgvEOff = []string{"stty", "-echo"}
sttyArgvEOn = []string{"stty", "echo"}
)
// getPassword gets input hidden from the terminal from a user. This is
// accomplished by turning off terminal echo, reading input from the user and
// finally turning on terminal echo.
func getPassword() (password string, err error) {
sig := make(chan os.Signal, 10)
brk := make(chan bool)
// File descriptors for stdin, stdout, and stderr.
fd := []uintptr{os.Stdin.Fd(), os.Stdout.Fd(), os.Stderr.Fd()}
// Setup notifications of termination signals to channel sig, create a process to
// watch for these signals so we can turn back on echo if need be.
signal.Notify(sig, syscall.SIGHUP, syscall.SIGINT, syscall.SIGKILL, syscall.SIGQUIT,
syscall.SIGTERM)
go catchSignal(fd, sig, brk)
// Turn off the terminal echo.
pid, err := echoOff(fd)
if err != nil {
return "", err
}
// Turn on the terminal echo and stop listening for signals.
defer signal.Stop(sig)
defer close(brk)
defer echoOn(fd)
syscall.Wait4(pid, nil, 0, nil)
line, err := readline()
if err == nil {
password = strings.TrimSpace(line)
} else {
err = fmt.Errorf("failed during password entry: %s", err)
}
return password, err
}
// echoOff turns off the terminal echo.
func echoOff(fd []uintptr) (int, error) {
pid, err := syscall.ForkExec(sttyArg0, sttyArgvEOff, &syscall.ProcAttr{Dir: "", Files: fd})
if err != nil {
return 0, fmt.Errorf("failed turning off console echo for password entry:\n\t%s", err)
}
return pid, nil
}
// echoOn turns back on the terminal echo.
func echoOn(fd []uintptr) {
// Turn on the terminal echo.
pid, e := syscall.ForkExec(sttyArg0, sttyArgvEOn, &syscall.ProcAttr{Dir: "", Files: fd})
if e == nil {
syscall.Wait4(pid, nil, 0, nil)
}
}
// catchSignal tries to catch SIGKILL, SIGQUIT and SIGINT so that we can turn
// terminal echo back on before the program ends. Otherwise the user is left
// with echo off on their terminal.
func catchSignal(fd []uintptr, sig chan os.Signal, brk chan bool) {
select {
case <-sig:
echoOn(fd)
os.Exit(-1)
case <-brk:
}
}

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@ -1,43 +0,0 @@
// +build windows
package speakeasy
import (
"os"
"syscall"
)
// SetConsoleMode function can be used to change value of ENABLE_ECHO_INPUT:
// http://msdn.microsoft.com/en-us/library/windows/desktop/ms686033(v=vs.85).aspx
const ENABLE_ECHO_INPUT = 0x0004
func getPassword() (password string, err error) {
hStdin := syscall.Handle(os.Stdin.Fd())
var oldMode uint32
err = syscall.GetConsoleMode(hStdin, &oldMode)
if err != nil {
return
}
var newMode uint32 = (oldMode &^ ENABLE_ECHO_INPUT)
err = setConsoleMode(hStdin, newMode)
defer setConsoleMode(hStdin, oldMode)
if err != nil {
return
}
return readline()
}
func setConsoleMode(console syscall.Handle, mode uint32) (err error) {
dll := syscall.MustLoadDLL("kernel32")
proc := dll.MustFindProc("SetConsoleMode")
r, _, err := proc.Call(uintptr(console), uintptr(mode))
if r == 0 {
return err
}
return nil
}

View File

@ -1,4 +0,0 @@
*.prof
*.test
*.swp
/bin/

View File

@ -1,20 +0,0 @@
The MIT License (MIT)
Copyright (c) 2013 Ben Johnson
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

View File

@ -1,18 +0,0 @@
BRANCH=`git rev-parse --abbrev-ref HEAD`
COMMIT=`git rev-parse --short HEAD`
GOLDFLAGS="-X main.branch $(BRANCH) -X main.commit $(COMMIT)"
default: build
race:
@go test -v -race -test.run="TestSimulate_(100op|1000op)"
# go get github.com/kisielk/errcheck
errcheck:
@errcheck -ignorepkg=bytes -ignore=os:Remove github.com/boltdb/bolt
test:
@go test -v -cover .
@go test -v ./cmd/bolt
.PHONY: fmt test

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@ -1,843 +0,0 @@
Bolt [![Build Status](https://drone.io/github.com/boltdb/bolt/status.png)](https://drone.io/github.com/boltdb/bolt/latest) [![Coverage Status](https://coveralls.io/repos/boltdb/bolt/badge.svg?branch=master)](https://coveralls.io/r/boltdb/bolt?branch=master) [![GoDoc](https://godoc.org/github.com/boltdb/bolt?status.svg)](https://godoc.org/github.com/boltdb/bolt) ![Version](https://img.shields.io/badge/version-1.0-green.svg)
====
Bolt is a pure Go key/value store inspired by [Howard Chu's][hyc_symas]
[LMDB project][lmdb]. The goal of the project is to provide a simple,
fast, and reliable database for projects that don't require a full database
server such as Postgres or MySQL.
Since Bolt is meant to be used as such a low-level piece of functionality,
simplicity is key. The API will be small and only focus on getting values
and setting values. That's it.
[hyc_symas]: https://twitter.com/hyc_symas
[lmdb]: http://symas.com/mdb/
## Project Status
Bolt is stable and the API is fixed. Full unit test coverage and randomized
black box testing are used to ensure database consistency and thread safety.
Bolt is currently in high-load production environments serving databases as
large as 1TB. Many companies such as Shopify and Heroku use Bolt-backed
services every day.
## Table of Contents
- [Getting Started](#getting-started)
- [Installing](#installing)
- [Opening a database](#opening-a-database)
- [Transactions](#transactions)
- [Read-write transactions](#read-write-transactions)
- [Read-only transactions](#read-only-transactions)
- [Batch read-write transactions](#batch-read-write-transactions)
- [Managing transactions manually](#managing-transactions-manually)
- [Using buckets](#using-buckets)
- [Using key/value pairs](#using-keyvalue-pairs)
- [Autoincrementing integer for the bucket](#autoincrementing-integer-for-the-bucket)
- [Iterating over keys](#iterating-over-keys)
- [Prefix scans](#prefix-scans)
- [Range scans](#range-scans)
- [ForEach()](#foreach)
- [Nested buckets](#nested-buckets)
- [Database backups](#database-backups)
- [Statistics](#statistics)
- [Read-Only Mode](#read-only-mode)
- [Mobile Use (iOS/Android)](#mobile-use-iosandroid)
- [Resources](#resources)
- [Comparison with other databases](#comparison-with-other-databases)
- [Postgres, MySQL, & other relational databases](#postgres-mysql--other-relational-databases)
- [LevelDB, RocksDB](#leveldb-rocksdb)
- [LMDB](#lmdb)
- [Caveats & Limitations](#caveats--limitations)
- [Reading the Source](#reading-the-source)
- [Other Projects Using Bolt](#other-projects-using-bolt)
## Getting Started
### Installing
To start using Bolt, install Go and run `go get`:
```sh
$ go get github.com/boltdb/bolt/...
```
This will retrieve the library and install the `bolt` command line utility into
your `$GOBIN` path.
### Opening a database
The top-level object in Bolt is a `DB`. It is represented as a single file on
your disk and represents a consistent snapshot of your data.
To open your database, simply use the `bolt.Open()` function:
```go
package main
import (
"log"
"github.com/boltdb/bolt"
)
func main() {
// Open the my.db data file in your current directory.
// It will be created if it doesn't exist.
db, err := bolt.Open("my.db", 0600, nil)
if err != nil {
log.Fatal(err)
}
defer db.Close()
...
}
```
Please note that Bolt obtains a file lock on the data file so multiple processes
cannot open the same database at the same time. Opening an already open Bolt
database will cause it to hang until the other process closes it. To prevent
an indefinite wait you can pass a timeout option to the `Open()` function:
```go
db, err := bolt.Open("my.db", 0600, &bolt.Options{Timeout: 1 * time.Second})
```
### Transactions
Bolt allows only one read-write transaction at a time but allows as many
read-only transactions as you want at a time. Each transaction has a consistent
view of the data as it existed when the transaction started.
Individual transactions and all objects created from them (e.g. buckets, keys)
are not thread safe. To work with data in multiple goroutines you must start
a transaction for each one or use locking to ensure only one goroutine accesses
a transaction at a time. Creating transaction from the `DB` is thread safe.
Read-only transactions and read-write transactions should not depend on one
another and generally shouldn't be opened simultaneously in the same goroutine.
This can cause a deadlock as the read-write transaction needs to periodically
re-map the data file but it cannot do so while a read-only transaction is open.
#### Read-write transactions
To start a read-write transaction, you can use the `DB.Update()` function:
```go
err := db.Update(func(tx *bolt.Tx) error {
...
return nil
})
```
Inside the closure, you have a consistent view of the database. You commit the
transaction by returning `nil` at the end. You can also rollback the transaction
at any point by returning an error. All database operations are allowed inside
a read-write transaction.
Always check the return error as it will report any disk failures that can cause
your transaction to not complete. If you return an error within your closure
it will be passed through.
#### Read-only transactions
To start a read-only transaction, you can use the `DB.View()` function:
```go
err := db.View(func(tx *bolt.Tx) error {
...
return nil
})
```
You also get a consistent view of the database within this closure, however,
no mutating operations are allowed within a read-only transaction. You can only
retrieve buckets, retrieve values, and copy the database within a read-only
transaction.
#### Batch read-write transactions
Each `DB.Update()` waits for disk to commit the writes. This overhead
can be minimized by combining multiple updates with the `DB.Batch()`
function:
```go
err := db.Batch(func(tx *bolt.Tx) error {
...
return nil
})
```
Concurrent Batch calls are opportunistically combined into larger
transactions. Batch is only useful when there are multiple goroutines
calling it.
The trade-off is that `Batch` can call the given
function multiple times, if parts of the transaction fail. The
function must be idempotent and side effects must take effect only
after a successful return from `DB.Batch()`.
For example: don't display messages from inside the function, instead
set variables in the enclosing scope:
```go
var id uint64
err := db.Batch(func(tx *bolt.Tx) error {
// Find last key in bucket, decode as bigendian uint64, increment
// by one, encode back to []byte, and add new key.
...
id = newValue
return nil
})
if err != nil {
return ...
}
fmt.Println("Allocated ID %d", id)
```
#### Managing transactions manually
The `DB.View()` and `DB.Update()` functions are wrappers around the `DB.Begin()`
function. These helper functions will start the transaction, execute a function,
and then safely close your transaction if an error is returned. This is the
recommended way to use Bolt transactions.
However, sometimes you may want to manually start and end your transactions.
You can use the `Tx.Begin()` function directly but **please** be sure to close
the transaction.
```go
// Start a writable transaction.
tx, err := db.Begin(true)
if err != nil {
return err
}
defer tx.Rollback()
// Use the transaction...
_, err := tx.CreateBucket([]byte("MyBucket"))
if err != nil {
return err
}
// Commit the transaction and check for error.
if err := tx.Commit(); err != nil {
return err
}
```
The first argument to `DB.Begin()` is a boolean stating if the transaction
should be writable.
### Using buckets
Buckets are collections of key/value pairs within the database. All keys in a
bucket must be unique. You can create a bucket using the `DB.CreateBucket()`
function:
```go
db.Update(func(tx *bolt.Tx) error {
b, err := tx.CreateBucket([]byte("MyBucket"))
if err != nil {
return fmt.Errorf("create bucket: %s", err)
}
return nil
})
```
You can also create a bucket only if it doesn't exist by using the
`Tx.CreateBucketIfNotExists()` function. It's a common pattern to call this
function for all your top-level buckets after you open your database so you can
guarantee that they exist for future transactions.
To delete a bucket, simply call the `Tx.DeleteBucket()` function.
### Using key/value pairs
To save a key/value pair to a bucket, use the `Bucket.Put()` function:
```go
db.Update(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte("MyBucket"))
err := b.Put([]byte("answer"), []byte("42"))
return err
})
```
This will set the value of the `"answer"` key to `"42"` in the `MyBucket`
bucket. To retrieve this value, we can use the `Bucket.Get()` function:
```go
db.View(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte("MyBucket"))
v := b.Get([]byte("answer"))
fmt.Printf("The answer is: %s\n", v)
return nil
})
```
The `Get()` function does not return an error because its operation is
guaranteed to work (unless there is some kind of system failure). If the key
exists then it will return its byte slice value. If it doesn't exist then it
will return `nil`. It's important to note that you can have a zero-length value
set to a key which is different than the key not existing.
Use the `Bucket.Delete()` function to delete a key from the bucket.
Please note that values returned from `Get()` are only valid while the
transaction is open. If you need to use a value outside of the transaction
then you must use `copy()` to copy it to another byte slice.
### Autoincrementing integer for the bucket
By using the `NextSequence()` function, you can let Bolt determine a sequence
which can be used as the unique identifier for your key/value pairs. See the
example below.
```go
// CreateUser saves u to the store. The new user ID is set on u once the data is persisted.
func (s *Store) CreateUser(u *User) error {
return s.db.Update(func(tx *bolt.Tx) error {
// Retrieve the users bucket.
// This should be created when the DB is first opened.
b := tx.Bucket([]byte("users"))
// Generate ID for the user.
// This returns an error only if the Tx is closed or not writeable.
// That can't happen in an Update() call so I ignore the error check.
id, _ = b.NextSequence()
u.ID = int(id)
// Marshal user data into bytes.
buf, err := json.Marshal(u)
if err != nil {
return err
}
// Persist bytes to users bucket.
return b.Put(itob(u.ID), buf)
})
}
// itob returns an 8-byte big endian representation of v.
func itob(v int) []byte {
b := make([]byte, 8)
binary.BigEndian.PutUint64(b, uint64(v))
return b
}
type User struct {
ID int
...
}
```
### Iterating over keys
Bolt stores its keys in byte-sorted order within a bucket. This makes sequential
iteration over these keys extremely fast. To iterate over keys we'll use a
`Cursor`:
```go
db.View(func(tx *bolt.Tx) error {
// Assume bucket exists and has keys
b := tx.Bucket([]byte("MyBucket"))
c := b.Cursor()
for k, v := c.First(); k != nil; k, v = c.Next() {
fmt.Printf("key=%s, value=%s\n", k, v)
}
return nil
})
```
The cursor allows you to move to a specific point in the list of keys and move
forward or backward through the keys one at a time.
The following functions are available on the cursor:
```
First() Move to the first key.
Last() Move to the last key.
Seek() Move to a specific key.
Next() Move to the next key.
Prev() Move to the previous key.
```
Each of those functions has a return signature of `(key []byte, value []byte)`.
When you have iterated to the end of the cursor then `Next()` will return a
`nil` key. You must seek to a position using `First()`, `Last()`, or `Seek()`
before calling `Next()` or `Prev()`. If you do not seek to a position then
these functions will return a `nil` key.
During iteration, if the key is non-`nil` but the value is `nil`, that means
the key refers to a bucket rather than a value. Use `Bucket.Bucket()` to
access the sub-bucket.
#### Prefix scans
To iterate over a key prefix, you can combine `Seek()` and `bytes.HasPrefix()`:
```go
db.View(func(tx *bolt.Tx) error {
// Assume bucket exists and has keys
c := tx.Bucket([]byte("MyBucket")).Cursor()
prefix := []byte("1234")
for k, v := c.Seek(prefix); bytes.HasPrefix(k, prefix); k, v = c.Next() {
fmt.Printf("key=%s, value=%s\n", k, v)
}
return nil
})
```
#### Range scans
Another common use case is scanning over a range such as a time range. If you
use a sortable time encoding such as RFC3339 then you can query a specific
date range like this:
```go
db.View(func(tx *bolt.Tx) error {
// Assume our events bucket exists and has RFC3339 encoded time keys.
c := tx.Bucket([]byte("Events")).Cursor()
// Our time range spans the 90's decade.
min := []byte("1990-01-01T00:00:00Z")
max := []byte("2000-01-01T00:00:00Z")
// Iterate over the 90's.
for k, v := c.Seek(min); k != nil && bytes.Compare(k, max) <= 0; k, v = c.Next() {
fmt.Printf("%s: %s\n", k, v)
}
return nil
})
```
#### ForEach()
You can also use the function `ForEach()` if you know you'll be iterating over
all the keys in a bucket:
```go
db.View(func(tx *bolt.Tx) error {
// Assume bucket exists and has keys
b := tx.Bucket([]byte("MyBucket"))
b.ForEach(func(k, v []byte) error {
fmt.Printf("key=%s, value=%s\n", k, v)
return nil
})
return nil
})
```
### Nested buckets
You can also store a bucket in a key to create nested buckets. The API is the
same as the bucket management API on the `DB` object:
```go
func (*Bucket) CreateBucket(key []byte) (*Bucket, error)
func (*Bucket) CreateBucketIfNotExists(key []byte) (*Bucket, error)
func (*Bucket) DeleteBucket(key []byte) error
```
### Database backups
Bolt is a single file so it's easy to backup. You can use the `Tx.WriteTo()`
function to write a consistent view of the database to a writer. If you call
this from a read-only transaction, it will perform a hot backup and not block
your other database reads and writes.
By default, it will use a regular file handle which will utilize the operating
system's page cache. See the [`Tx`](https://godoc.org/github.com/boltdb/bolt#Tx)
documentation for information about optimizing for larger-than-RAM datasets.
One common use case is to backup over HTTP so you can use tools like `cURL` to
do database backups:
```go
func BackupHandleFunc(w http.ResponseWriter, req *http.Request) {
err := db.View(func(tx *bolt.Tx) error {
w.Header().Set("Content-Type", "application/octet-stream")
w.Header().Set("Content-Disposition", `attachment; filename="my.db"`)
w.Header().Set("Content-Length", strconv.Itoa(int(tx.Size())))
_, err := tx.WriteTo(w)
return err
})
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
```
Then you can backup using this command:
```sh
$ curl http://localhost/backup > my.db
```
Or you can open your browser to `http://localhost/backup` and it will download
automatically.
If you want to backup to another file you can use the `Tx.CopyFile()` helper
function.
### Statistics
The database keeps a running count of many of the internal operations it
performs so you can better understand what's going on. By grabbing a snapshot
of these stats at two points in time we can see what operations were performed
in that time range.
For example, we could start a goroutine to log stats every 10 seconds:
```go
go func() {
// Grab the initial stats.
prev := db.Stats()
for {
// Wait for 10s.
time.Sleep(10 * time.Second)
// Grab the current stats and diff them.
stats := db.Stats()
diff := stats.Sub(&prev)
// Encode stats to JSON and print to STDERR.
json.NewEncoder(os.Stderr).Encode(diff)
// Save stats for the next loop.
prev = stats
}
}()
```
It's also useful to pipe these stats to a service such as statsd for monitoring
or to provide an HTTP endpoint that will perform a fixed-length sample.
### Read-Only Mode
Sometimes it is useful to create a shared, read-only Bolt database. To this,
set the `Options.ReadOnly` flag when opening your database. Read-only mode
uses a shared lock to allow multiple processes to read from the database but
it will block any processes from opening the database in read-write mode.
```go
db, err := bolt.Open("my.db", 0666, &bolt.Options{ReadOnly: true})
if err != nil {
log.Fatal(err)
}
```
### Mobile Use (iOS/Android)
Bolt is able to run on mobile devices by leveraging the binding feature of the
[gomobile](https://github.com/golang/mobile) tool. Create a struct that will
contain your database logic and a reference to a `*bolt.DB` with a initializing
contstructor that takes in a filepath where the database file will be stored.
Neither Android nor iOS require extra permissions or cleanup from using this method.
```go
func NewBoltDB(filepath string) *BoltDB {
db, err := bolt.Open(filepath+"/demo.db", 0600, nil)
if err != nil {
log.Fatal(err)
}
return &BoltDB{db}
}
type BoltDB struct {
db *bolt.DB
...
}
func (b *BoltDB) Path() string {
return b.db.Path()
}
func (b *BoltDB) Close() {
b.db.Close()
}
```
Database logic should be defined as methods on this wrapper struct.
To initialize this struct from the native language (both platforms now sync
their local storage to the cloud. These snippets disable that functionality for the
database file):
#### Android
```java
String path;
if (android.os.Build.VERSION.SDK_INT >=android.os.Build.VERSION_CODES.LOLLIPOP){
path = getNoBackupFilesDir().getAbsolutePath();
} else{
path = getFilesDir().getAbsolutePath();
}
Boltmobiledemo.BoltDB boltDB = Boltmobiledemo.NewBoltDB(path)
```
#### iOS
```objc
- (void)demo {
NSString* path = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,
NSUserDomainMask,
YES) objectAtIndex:0];
GoBoltmobiledemoBoltDB * demo = GoBoltmobiledemoNewBoltDB(path);
[self addSkipBackupAttributeToItemAtPath:demo.path];
//Some DB Logic would go here
[demo close];
}
- (BOOL)addSkipBackupAttributeToItemAtPath:(NSString *) filePathString
{
NSURL* URL= [NSURL fileURLWithPath: filePathString];
assert([[NSFileManager defaultManager] fileExistsAtPath: [URL path]]);
NSError *error = nil;
BOOL success = [URL setResourceValue: [NSNumber numberWithBool: YES]
forKey: NSURLIsExcludedFromBackupKey error: &error];
if(!success){
NSLog(@"Error excluding %@ from backup %@", [URL lastPathComponent], error);
}
return success;
}
```
## Resources
For more information on getting started with Bolt, check out the following articles:
* [Intro to BoltDB: Painless Performant Persistence](http://npf.io/2014/07/intro-to-boltdb-painless-performant-persistence/) by [Nate Finch](https://github.com/natefinch).
* [Bolt -- an embedded key/value database for Go](https://www.progville.com/go/bolt-embedded-db-golang/) by Progville
## Comparison with other databases
### Postgres, MySQL, & other relational databases
Relational databases structure data into rows and are only accessible through
the use of SQL. This approach provides flexibility in how you store and query
your data but also incurs overhead in parsing and planning SQL statements. Bolt
accesses all data by a byte slice key. This makes Bolt fast to read and write
data by key but provides no built-in support for joining values together.
Most relational databases (with the exception of SQLite) are standalone servers
that run separately from your application. This gives your systems
flexibility to connect multiple application servers to a single database
server but also adds overhead in serializing and transporting data over the
network. Bolt runs as a library included in your application so all data access
has to go through your application's process. This brings data closer to your
application but limits multi-process access to the data.
### LevelDB, RocksDB
LevelDB and its derivatives (RocksDB, HyperLevelDB) are similar to Bolt in that
they are libraries bundled into the application, however, their underlying
structure is a log-structured merge-tree (LSM tree). An LSM tree optimizes
random writes by using a write ahead log and multi-tiered, sorted files called
SSTables. Bolt uses a B+tree internally and only a single file. Both approaches
have trade-offs.
If you require a high random write throughput (>10,000 w/sec) or you need to use
spinning disks then LevelDB could be a good choice. If your application is
read-heavy or does a lot of range scans then Bolt could be a good choice.
One other important consideration is that LevelDB does not have transactions.
It supports batch writing of key/values pairs and it supports read snapshots
but it will not give you the ability to do a compare-and-swap operation safely.
Bolt supports fully serializable ACID transactions.
### LMDB
Bolt was originally a port of LMDB so it is architecturally similar. Both use
a B+tree, have ACID semantics with fully serializable transactions, and support
lock-free MVCC using a single writer and multiple readers.
The two projects have somewhat diverged. LMDB heavily focuses on raw performance
while Bolt has focused on simplicity and ease of use. For example, LMDB allows
several unsafe actions such as direct writes for the sake of performance. Bolt
opts to disallow actions which can leave the database in a corrupted state. The
only exception to this in Bolt is `DB.NoSync`.
There are also a few differences in API. LMDB requires a maximum mmap size when
opening an `mdb_env` whereas Bolt will handle incremental mmap resizing
automatically. LMDB overloads the getter and setter functions with multiple
flags whereas Bolt splits these specialized cases into their own functions.
## Caveats & Limitations
It's important to pick the right tool for the job and Bolt is no exception.
Here are a few things to note when evaluating and using Bolt:
* Bolt is good for read intensive workloads. Sequential write performance is
also fast but random writes can be slow. You can use `DB.Batch()` or add a
write-ahead log to help mitigate this issue.
* Bolt uses a B+tree internally so there can be a lot of random page access.
SSDs provide a significant performance boost over spinning disks.
* Try to avoid long running read transactions. Bolt uses copy-on-write so
old pages cannot be reclaimed while an old transaction is using them.
* Byte slices returned from Bolt are only valid during a transaction. Once the
transaction has been committed or rolled back then the memory they point to
can be reused by a new page or can be unmapped from virtual memory and you'll
see an `unexpected fault address` panic when accessing it.
* Be careful when using `Bucket.FillPercent`. Setting a high fill percent for
buckets that have random inserts will cause your database to have very poor
page utilization.
* Use larger buckets in general. Smaller buckets causes poor page utilization
once they become larger than the page size (typically 4KB).
* Bulk loading a lot of random writes into a new bucket can be slow as the
page will not split until the transaction is committed. Randomly inserting
more than 100,000 key/value pairs into a single new bucket in a single
transaction is not advised.
* Bolt uses a memory-mapped file so the underlying operating system handles the
caching of the data. Typically, the OS will cache as much of the file as it
can in memory and will release memory as needed to other processes. This means
that Bolt can show very high memory usage when working with large databases.
However, this is expected and the OS will release memory as needed. Bolt can
handle databases much larger than the available physical RAM, provided its
memory-map fits in the process virtual address space. It may be problematic
on 32-bits systems.
* The data structures in the Bolt database are memory mapped so the data file
will be endian specific. This means that you cannot copy a Bolt file from a
little endian machine to a big endian machine and have it work. For most
users this is not a concern since most modern CPUs are little endian.
* Because of the way pages are laid out on disk, Bolt cannot truncate data files
and return free pages back to the disk. Instead, Bolt maintains a free list
of unused pages within its data file. These free pages can be reused by later
transactions. This works well for many use cases as databases generally tend
to grow. However, it's important to note that deleting large chunks of data
will not allow you to reclaim that space on disk.
For more information on page allocation, [see this comment][page-allocation].
[page-allocation]: https://github.com/boltdb/bolt/issues/308#issuecomment-74811638
## Reading the Source
Bolt is a relatively small code base (<3KLOC) for an embedded, serializable,
transactional key/value database so it can be a good starting point for people
interested in how databases work.
The best places to start are the main entry points into Bolt:
- `Open()` - Initializes the reference to the database. It's responsible for
creating the database if it doesn't exist, obtaining an exclusive lock on the
file, reading the meta pages, & memory-mapping the file.
- `DB.Begin()` - Starts a read-only or read-write transaction depending on the
value of the `writable` argument. This requires briefly obtaining the "meta"
lock to keep track of open transactions. Only one read-write transaction can
exist at a time so the "rwlock" is acquired during the life of a read-write
transaction.
- `Bucket.Put()` - Writes a key/value pair into a bucket. After validating the
arguments, a cursor is used to traverse the B+tree to the page and position
where they key & value will be written. Once the position is found, the bucket
materializes the underlying page and the page's parent pages into memory as
"nodes". These nodes are where mutations occur during read-write transactions.
These changes get flushed to disk during commit.
- `Bucket.Get()` - Retrieves a key/value pair from a bucket. This uses a cursor
to move to the page & position of a key/value pair. During a read-only
transaction, the key and value data is returned as a direct reference to the
underlying mmap file so there's no allocation overhead. For read-write
transactions, this data may reference the mmap file or one of the in-memory
node values.
- `Cursor` - This object is simply for traversing the B+tree of on-disk pages
or in-memory nodes. It can seek to a specific key, move to the first or last
value, or it can move forward or backward. The cursor handles the movement up
and down the B+tree transparently to the end user.
- `Tx.Commit()` - Converts the in-memory dirty nodes and the list of free pages
into pages to be written to disk. Writing to disk then occurs in two phases.
First, the dirty pages are written to disk and an `fsync()` occurs. Second, a
new meta page with an incremented transaction ID is written and another
`fsync()` occurs. This two phase write ensures that partially written data
pages are ignored in the event of a crash since the meta page pointing to them
is never written. Partially written meta pages are invalidated because they
are written with a checksum.
If you have additional notes that could be helpful for others, please submit
them via pull request.
## Other Projects Using Bolt
Below is a list of public, open source projects that use Bolt:
* [Operation Go: A Routine Mission](http://gocode.io) - An online programming game for Golang using Bolt for user accounts and a leaderboard.
* [Bazil](https://bazil.org/) - A file system that lets your data reside where it is most convenient for it to reside.
* [DVID](https://github.com/janelia-flyem/dvid) - Added Bolt as optional storage engine and testing it against Basho-tuned leveldb.
* [Skybox Analytics](https://github.com/skybox/skybox) - A standalone funnel analysis tool for web analytics.
* [Scuttlebutt](https://github.com/benbjohnson/scuttlebutt) - Uses Bolt to store and process all Twitter mentions of GitHub projects.
* [Wiki](https://github.com/peterhellberg/wiki) - A tiny wiki using Goji, BoltDB and Blackfriday.
* [ChainStore](https://github.com/pressly/chainstore) - Simple key-value interface to a variety of storage engines organized as a chain of operations.
* [MetricBase](https://github.com/msiebuhr/MetricBase) - Single-binary version of Graphite.
* [Gitchain](https://github.com/gitchain/gitchain) - Decentralized, peer-to-peer Git repositories aka "Git meets Bitcoin".
* [event-shuttle](https://github.com/sclasen/event-shuttle) - A Unix system service to collect and reliably deliver messages to Kafka.
* [ipxed](https://github.com/kelseyhightower/ipxed) - Web interface and api for ipxed.
* [BoltStore](https://github.com/yosssi/boltstore) - Session store using Bolt.
* [photosite/session](https://godoc.org/bitbucket.org/kardianos/photosite/session) - Sessions for a photo viewing site.
* [LedisDB](https://github.com/siddontang/ledisdb) - A high performance NoSQL, using Bolt as optional storage.
* [ipLocator](https://github.com/AndreasBriese/ipLocator) - A fast ip-geo-location-server using bolt with bloom filters.
* [cayley](https://github.com/google/cayley) - Cayley is an open-source graph database using Bolt as optional backend.
* [bleve](http://www.blevesearch.com/) - A pure Go search engine similar to ElasticSearch that uses Bolt as the default storage backend.
* [tentacool](https://github.com/optiflows/tentacool) - REST api server to manage system stuff (IP, DNS, Gateway...) on a linux server.
* [SkyDB](https://github.com/skydb/sky) - Behavioral analytics database.
* [Seaweed File System](https://github.com/chrislusf/seaweedfs) - Highly scalable distributed key~file system with O(1) disk read.
* [InfluxDB](https://influxdata.com) - Scalable datastore for metrics, events, and real-time analytics.
* [Freehold](http://tshannon.bitbucket.org/freehold/) - An open, secure, and lightweight platform for your files and data.
* [Prometheus Annotation Server](https://github.com/oliver006/prom_annotation_server) - Annotation server for PromDash & Prometheus service monitoring system.
* [Consul](https://github.com/hashicorp/consul) - Consul is service discovery and configuration made easy. Distributed, highly available, and datacenter-aware.
* [Kala](https://github.com/ajvb/kala) - Kala is a modern job scheduler optimized to run on a single node. It is persistent, JSON over HTTP API, ISO 8601 duration notation, and dependent jobs.
* [drive](https://github.com/odeke-em/drive) - drive is an unofficial Google Drive command line client for \*NIX operating systems.
* [stow](https://github.com/djherbis/stow) - a persistence manager for objects
backed by boltdb.
* [buckets](https://github.com/joyrexus/buckets) - a bolt wrapper streamlining
simple tx and key scans.
* [mbuckets](https://github.com/abhigupta912/mbuckets) - A Bolt wrapper that allows easy operations on multi level (nested) buckets.
* [Request Baskets](https://github.com/darklynx/request-baskets) - A web service to collect arbitrary HTTP requests and inspect them via REST API or simple web UI, similar to [RequestBin](http://requestb.in/) service
* [Go Report Card](https://goreportcard.com/) - Go code quality report cards as a (free and open source) service.
* [Boltdb Boilerplate](https://github.com/bobintornado/boltdb-boilerplate) - Boilerplate wrapper around bolt aiming to make simple calls one-liners.
If you are using Bolt in a project please send a pull request to add it to the list.

View File

@ -1,7 +0,0 @@
package bolt
// maxMapSize represents the largest mmap size supported by Bolt.
const maxMapSize = 0x7FFFFFFF // 2GB
// maxAllocSize is the size used when creating array pointers.
const maxAllocSize = 0xFFFFFFF

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@ -1,7 +0,0 @@
package bolt
// maxMapSize represents the largest mmap size supported by Bolt.
const maxMapSize = 0xFFFFFFFFFFFF // 256TB
// maxAllocSize is the size used when creating array pointers.
const maxAllocSize = 0x7FFFFFFF

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@ -1,7 +0,0 @@
package bolt
// maxMapSize represents the largest mmap size supported by Bolt.
const maxMapSize = 0x7FFFFFFF // 2GB
// maxAllocSize is the size used when creating array pointers.
const maxAllocSize = 0xFFFFFFF

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@ -1,9 +0,0 @@
// +build arm64
package bolt
// maxMapSize represents the largest mmap size supported by Bolt.
const maxMapSize = 0xFFFFFFFFFFFF // 256TB
// maxAllocSize is the size used when creating array pointers.
const maxAllocSize = 0x7FFFFFFF

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