version: bump up to 3.5.6

[3.5] trim build path

.github/ISSUE_TEMPLATE.md

@@ -1,2 +1,2 @@
 
-Please read https://github.com/etcd-io/etcd/blob/master/Documentation/reporting-bugs.md.
+Please read https://etcd.io/docs/latest/reporting_bugs/

.github/ISSUE_TEMPLATE/distributors-application.md

@@ -0,0 +1,28 @@
+---
+name: Distributors Application
+title: Distributors Application for <YOUR DISTRIBUTION HERE>
+about: Apply for membership of security@etcd.io
+---
+
+<!--
+Please answer the following questions and provide supporting evidence for
+meeting the membership criteria.
+-->
+
+**Actively monitored security email alias for our project:**
+
+**1. Have a user base not limited to your own organization.**
+
+**2. Have a publicly verifiable track record up to present day of fixing security issues.**
+
+**3. Not be a downstream or rebuild of another distribution.**
+
+**4. Be a participant and active contributor in the community.**
+
+**5. Accept the Embargo Policy.**
+<!-- https://github.com/etcd-io/etcd/blob/main/security/security-release-process.md#disclosures -->
+
+**6. Be willing to contribute back.**
+<!-- Per https://github.com/etcd-io/etcd/blob/main/security/security-release-process.md#patch-release-and-public-communication -->
+
+**7. Have someone already on the list vouch for the person requesting membership on behalf of your distribution.**

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,2 +1,2 @@
 
-Please read https://github.com/etcd-io/etcd/blob/master/CONTRIBUTING.md#contribution-flow.
+Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

.github/SECURITY.md

@@ -1,2 +1,2 @@
 
-Please read https://github.com/etcd-io/etcd/blob/master/security/README.md.
+Please read https://github.com/etcd-io/etcd/blob/main/security/README.md.

.github/workflows/codeql-analysis.yml

@@ -13,10 +13,10 @@ name: "CodeQL"
 
 on:
   push:
-    branches: [ master, release-0.4, release-2.0, release-2.1, release-2.2, release-2.3, release-3.0, release-3.1 ]
+    branches: [ main, release-0.4, release-2.0, release-2.1, release-2.2, release-2.3, release-3.0, release-3.1 ]
   pull_request:
     # The branches below must be a subset of the branches above
-    branches: [ master ]
+    branches: [ main ]
   schedule:
     - cron: '20 14 * * 5'
 

.github/workflows/e2e.yaml

@@ -0,0 +1,35 @@
+name: E2E
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        target:
+        - linux-amd64-e2e
+        - linux-386-e2e
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-go@v2
+      with:
+        go-version: "1.16.15"
+    - run: date
+    - env:
+        TARGET: ${{ matrix.target }}
+      run: |
+        echo "${TARGET}"
+        case "${TARGET}" in
+          linux-amd64-e2e)
+            PASSES='build release e2e' MANUAL_VER=v3.4.7 CPU='4' EXPECT_DEBUG='true' COVER='false' RACE='true' ./test.sh 2>&1 | tee test.log
+            ! egrep "(--- FAIL:|DATA RACE|panic: test timed out|appears to have leaked)" -B50 -A10 test.log
+            ;;
+          linux-386-e2e)
+            GOARCH=386 PASSES='build e2e' CPU='4' EXPECT_DEBUG='true' COVER='false' RACE='true' ./test.sh 2>&1 | tee test.log
+            ! egrep "(--- FAIL:|DATA RACE|panic: test timed out|appears to have leaked)" -B50 -A10 test.log
+            ;;
+          *)
+            echo "Failed to find target"
+            exit 1
+            ;;
+        esac

.github/workflows/functional.yaml

@@ -0,0 +1,29 @@
+name: functional-tests
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        target:
+        - linux-amd64-functional
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-go@v2
+      with:
+        go-version: "1.16.15"
+    - run: date
+    - env:
+        TARGET: ${{ matrix.target }}
+      run: |
+        echo "${TARGET}"
+        case "${TARGET}" in
+          linux-amd64-functional)
+            GO_BUILD_FLAGS='-v -mod=readonly' ./build && GOARCH=amd64 PASSES='functional' ./test
+            ;;
+          *)
+            echo "Failed to find target"
+            exit 1
+            ;;
+        esac

.github/workflows/grpcproxy.yaml

@@ -0,0 +1,30 @@
+name: grpcProxy-tests
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        target:
+        - linux-amd64-grpcproxy
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-go@v2
+      with:
+        go-version: "1.16.15"
+    - run: date
+    - env:
+        TARGET: ${{ matrix.target }}
+      run: |
+        echo "${TARGET}"
+        case "${TARGET}" in
+          linux-amd64-grpcproxy)
+            PASSES='build grpcproxy'  CPU='4' COVER='false' RACE='true' ./test.sh 2>&1 | tee test.log
+            ! egrep "(--- FAIL:|DATA RACE|panic: test timed out|appears to have leaked)" -B50 -A10 test.log
+            ;;
+          *)
+            echo "Failed to find target"
+            exit 1
+            ;;
+        esac

.github/workflows/release.yaml

@@ -0,0 +1,24 @@
+name: Release
+on: [push, pull_request]
+jobs:
+  main:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-go@v2
+      with:
+        go-version: "1.16.15"
+    - run: |
+        git config --global user.email "github-action@etcd.io"
+        git config --global user.name "Github Action"
+        gpg --batch --gen-key <<EOF
+        %no-protection
+        Key-Type: 1
+        Key-Length: 2048
+        Subkey-Type: 1
+        Subkey-Length: 2048
+        Name-Real: Github Action
+        Name-Email: github-action@etcd.io
+        Expire-Date: 0
+        EOF
+        DRY_RUN=true BRANCH=release-3.5 ./scripts/release --no-upload --no-docker-push 3.5.99

.github/workflows/tests.yaml

@@ -0,0 +1,61 @@
+name: Tests
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target:
+        - linux-amd64-fmt
+        - linux-amd64-integration-1-cpu
+        - linux-amd64-integration-2-cpu
+        - linux-amd64-integration-4-cpu
+        - linux-amd64-unit-4-cpu-race
+        - all-build
+        - linux-386-unit-1-cpu
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-go@v2
+      with:
+        go-version: "1.16.15"
+    - run: date
+    - env:
+        TARGET: ${{ matrix.target }}
+      run: |
+        echo "${TARGET}"
+        case "${TARGET}" in
+          linux-amd64-fmt)
+            GOARCH=amd64 PASSES='fmt bom dep' ./test.sh
+            ;;
+          linux-amd64-integration-1-cpu)
+            GOARCH=amd64 CPU=1 PASSES='integration' RACE='false' ./test.sh
+            ;;
+          linux-amd64-integration-2-cpu)
+            GOARCH=amd64 CPU=2 PASSES='integration' RACE='false' ./test.sh
+            ;;
+          linux-amd64-integration-4-cpu)
+            GOARCH=amd64 CPU=4 PASSES='integration' RACE='false' ./test.sh
+            ;;
+          linux-amd64-unit-4-cpu-race)
+            GOARCH=amd64 PASSES='unit' RACE='true' CPU='4' ./test.sh -p=2
+            ;;
+          all-build)
+            GOARCH=amd64 PASSES='build' ./test.sh
+            GOARCH=386 PASSES='build' ./test.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOOS=darwin GOARCH=amd64 ./build.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOOS=darwin GOARCH=arm64 ./build.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOOS=windows GOARCH=amd64 ./build.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=arm ./build.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=arm64 ./build.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=ppc64le ./build.sh
+            GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=s390x ./build.sh
+            ;;
+          linux-386-unit-1-cpu)
+            GOARCH=386 PASSES='unit' RACE='false' CPU='1' ./test -p=4
+            ;;
+          *)
+            echo "Failed to find target"
+            exit 1
+            ;;
+        esac

.travis.yml

@@ -6,7 +6,7 @@ sudo: required
 services: docker
 
 go:
-  - 1.15.7
+  - "1.16.15"
   - tip
 
 notifications:
@@ -15,48 +15,21 @@ notifications:
 
 env:
   matrix:
-    - TARGET=linux-amd64-fmt
-    - TARGET=linux-amd64-integration-1-cpu
-    - TARGET=linux-amd64-integration-2-cpu
-    - TARGET=linux-amd64-integration-4-cpu
-    - TARGET=linux-amd64-functional
-    - TARGET=linux-amd64-unit-4-cpu-race
-    - TARGET=all-build
-    - TARGET=linux-amd64-grpcproxy
     - TARGET=linux-amd64-coverage
     - TARGET=linux-amd64-fmt-unit-go-tip-2-cpu
-    - TARGET=linux-386-unit-1-cpu
 
 matrix:
   fast_finish: true
   allow_failures:
-    - go: 1.15.7
+    - go: "1.16.15"
       env: TARGET=linux-amd64-coverage
     - go: tip
       env: TARGET=linux-amd64-fmt-unit-go-tip-2-cpu
   exclude:
-    - go: tip
-      env: TARGET=linux-amd64-fmt
-    - go: tip
-      env: TARGET=linux-amd64-integration-1-cpu
-    - go: tip
-      env: TARGET=linux-amd64-integration-2-cpu
-    - go: tip
-      env: TARGET=linux-amd64-integration-4-cpu
-    - go: tip
-      env: TARGET=linux-amd64-functional
-    - go: tip
-      env: TARGET=linux-amd64-unit-4-cpu-race
-    - go: tip
-      env: TARGET=all-build
-    - go: tip
-      env: TARGET=linux-amd64-grpcproxy
     - go: tip
       env: TARGET=linux-amd64-coverage
-    - go: 1.14.3
+    - go: "1.16.15"
       env: TARGET=linux-amd64-fmt-unit-go-tip-2-cpu
-    - go: tip
-      env: TARGET=linux-386-unit-1-cpu
 
 before_install:
   - if [[ $TRAVIS_GO_VERSION == 1.* ]]; then docker pull gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION}; fi
@@ -69,64 +42,10 @@ script:
   - echo "TRAVIS_GO_VERSION=${TRAVIS_GO_VERSION}"
   - >
     case "${TARGET}" in
-      linux-amd64-fmt)
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=amd64 PASSES='fmt bom dep' ./test"
-        ;;
-      linux-amd64-integration-1-cpu)
-        # TODO: Reenable 'race' when https://github.com/etcd-io/etcd/issues/12336 fixed.
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=amd64 CPU=1 PASSES='integration' RACE='false' ./test"
-        ;;
-      linux-amd64-integration-2-cpu)
-        # TODO: Reenable 'race' when https://github.com/etcd-io/etcd/issues/12336 fixed.
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=amd64 CPU=2 PASSES='integration' RACE='false' ./test"
-        ;;
-      linux-amd64-integration-4-cpu)
-        # TODO: Reenable 'race' when https://github.com/etcd-io/etcd/issues/12336 fixed.
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=amd64 CPU=4 PASSES='integration' RACE='false' ./test"
-        ;;
-      linux-amd64-functional)
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GO_BUILD_FLAGS='-v -mod=readonly' ./build && GOARCH=amd64 PASSES='functional' ./test"
-        ;;
-      linux-amd64-unit-4-cpu-race)
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=amd64 PASSES='unit' RACE='true' CPU='4' ./test -p=2"
-        ;;
-      all-build)
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=amd64 PASSES='build' ./test \
-            && GOARCH=386 PASSES='build' ./test \
-            && GO_BUILD_FLAGS='-v -mod=readonly' GOOS=darwin GOARCH=amd64 ./build \
-            && GO_BUILD_FLAGS='-v -mod=readonly' GOOS=windows GOARCH=amd64 ./build \
-            && GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=arm ./build \
-            && GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=arm64 ./build \
-            && GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=ppc64le ./build \
-            && GO_BUILD_FLAGS='-v -mod=readonly' GOARCH=s390x ./build"
-        ;;
-      linux-amd64-grpcproxy)
-        # TODO: Reenable race when https://github.com/etcd-io/etcd/issues/12336 fixed.
-        sudo HOST_TMP_DIR=/tmp TEST_OPTS="PASSES='build grpcproxy' VERBOSE='1' CPU='4' COVER='false' RACE='false'" make docker-test
-        ;;
       linux-amd64-coverage)
         sudo HOST_TMP_DIR=/tmp TEST_OPTS="VERBOSE='1'" make docker-test-coverage
         ;;
       linux-amd64-fmt-unit-go-tip-2-cpu)
-        GOARCH=amd64 PASSES='fmt unit' CPU='2' RACE='false' ./test -p=2
-        ;;
-      linux-386-unit-1-cpu)
-        docker run --rm \
-          --volume=`pwd`:/go/src/go.etcd.io/etcd gcr.io/etcd-development/etcd-test:go${TRAVIS_GO_VERSION} \
-          /bin/bash -c "GOARCH=386 PASSES='unit' RACE='false' CPU='1' ./test -p=4"
+        GOARCH=amd64 PASSES='fmt unit' CPU='2' RACE='false' ./test.sh -p=2
         ;;
     esac

ADOPTERS.md

@@ -1,250 +0,0 @@
----
-title: 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 how etcd is working in the field and update this list.
-
-## All Kubernetes Users
-
-- *Application*: https://kubernetes.io/
-- *Environments*: AWS, OpenStack, Azure, Google Cloud, Huawei Cloud, Bare Metal, etc
-
-**This is a meta user; please feel free to document specific Kubernetes clusters!**
-
-All Kubernetes clusters use etcd as their primary data store. This means etcd's users include such companies as [Niantic, Inc Pokemon Go](https://cloudplatform.googleblog.com/2016/09/bringing-Pokemon-GO-to-life-on-Google-Cloud.html), [Box](https://blog.box.com/blog/kubernetes-box-microservices-maximum-velocity/), [CoreOS](https://coreos.com/tectonic), [Ticketmaster](https://www.youtube.com/watch?v=wqXVKneP0Hg), [Salesforce](https://www.salesforce.com) and many many more.
-
-## 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.
-
-## Vonage
-
-- *Application*: kubernetes, vault backend, system configuration for microservices, scheduling, locks (future - service discovery)
-- *Launched*: August 2015
-- *Cluster Size*: 2 clusters of 5 members in 2 DCs, n local proxies 1-to-1 with microservice, (ssl and SRV look up)
-- *Order of Data Size*: kilobytes
-- *Operator*: Vonage [devAdmin][raoofm]
-- *Environment*: VMWare, AWS
-- *Backups*: Daily snapshots on VMs. Backups done for upgrades.
-
-## PD
-
-- *Application*: embed etcd
-- *Launched*: Mar 2016
-- *Cluster Size*: 3 or 5 members
-- *Order of Data Size*: megabytes
-- *Operator*: PingCAP, Inc.
-- *Environment*: Bare Metal, AWS, etc.
-- *Backups*: None.
-
-PD(Placement Driver) is the central controller in the TiDB cluster. It saves the cluster meta information, schedule the data, allocate the global unique timestamp for the distributed transaction, etc. It embeds etcd to supply high availability and auto failover.
-
-## Huawei
-
-- *Application*: System configuration for overlay network (Canal)
-- *Launched*: June 2016
-- *Cluster Size*: 3 members for each cluster
-- *Order of Data Size*: kilobytes
-- *Operator*: Huawei Euler Department
-- *Environment*: [Huawei Cloud](http://www.hwclouds.com/product/cce.html)
-- *Backups*: None, all data can be recreated if necessary.
-
-[teamcity]: https://www.jetbrains.com/teamcity/
-[raoofm]:https://github.com/raoofm
-
-## Qiniu Cloud
-
-- *Application*: system configuration for microservices, distributed locks
-- *Launched*: Jan. 2016
-- *Cluster Size*: 3 members each with several clusters
-- *Order of Data Size*: kilobytes
-- *Operator*: Pandora, chenchao@qiniu.com
-- *Environment*: Baremetal
-- *Backups*: None, all data can be recreated if necessary
-
-## QingCloud
-
-- *Application*: [QingCloud][qingcloud] appcenter cluster for service discovery as [metad][metad] backend.
-- *Launched*: December 2016
-- *Cluster Size*: 1 cluster of 3 members per user.
-- *Order of Data Size*: kilobytes
-- *Operator*: [yunify][yunify]
-- *Environment*: QingCloud IaaS
-- *Backups*: None, all data can be recreated if necessary.
-
-[metad]:https://github.com/yunify/metad
-[yunify]:https://github.com/yunify
-[qingcloud]:https://qingcloud.com/
-
-
-## Yandex
-
-- *Application*: system configuration for services, service discovery
-- *Launched*: March 2016
-- *Cluster Size*: 3 clusters of 5 members
-- *Order of Data Size*: several gigabytes
-- *Operator*: Yandex; [nekto0n][nekto0n]
-- *Environment*: Bare Metal
-- *Backups*: None
-
-[nekto0n]:https://github.com/nekto0n
-
-## Tencent Games
-
-- *Application*: Meta data and configuration data for service discovery, Kubernetes, etc.
-- *Launched*: Jan. 2015
-- *Cluster Size*: 3 members each with 10s of clusters
-- *Order of Data Size*: 10s of Megabytes
-- *Operator*: Tencent Game Operations Department
-- *Environment*: Baremetal
-- *Backups*: Periodic sync to backup server
-
-In Tencent games, we use Docker and Kubernetes to deploy and run our applications, and use etcd to save meta data for service discovery, Kubernetes, etc.
-
-## Hyper.sh
-
-- *Application*: Kubernetes, distributed locks, etc.
-- *Launched*: April 2016
-- *Cluster Size*: 1 cluster of 3 members
-- *Order of Data Size*: 10s of MB
-- *Operator*: Hyper.sh
-- *Environment*: Baremetal
-- *Backups*: None, all data can be recreated if necessary.
-
-In [hyper.sh][hyper.sh], the container service is backed by [hypernetes][hypernetes], a multi-tenant kubernetes distro. Moreover, we use etcd to coordinate the multiple manage services and store global meta data.
-
-[hypernetes]:https://github.com/hyperhq/hypernetes
-[Hyper.sh]:https://www.hyper.sh
-
-## Meitu
-- *Application*: system configuration for services, service discovery, kubernetes in test environment
-- *Launched*: October 2015
-- *Cluster Size*: 1 cluster of 3 members
-- *Order of Data Size*: megabytes
-- *Operator*: Meitu, hxj@meitu.com, [shafreeck][shafreeck]
-- *Environment*: Bare Metal
-- *Backups*: None, all data can be recreated if necessary.
-
-[shafreeck]:https://github.com/shafreeck
-
-## Grab
-- *Application*: system configuration for services, service discovery
-- *Launched*: June 2016
-- *Cluster Size*: 1 cluster of 7 members
-- *Order of Data Size*: megabytes
-- *Operator*: Grab, [taxitan][taxitan], [reterVision][reterVision]
-- *Environment*: AWS
-- *Backups*: None, all data can be recreated if necessary.
-
-[taxitan]:https://github.com/taxitan
-[reterVision]:https://github.com/reterVision
-
-## DaoCloud.io
-
-- *Application*: container management
-- *Launched*: Sep. 2015
-- *Cluster Size*: 1000+ deployments, each deployment contains a 3 node cluster.
-- *Order of Data Size*: 100s of Megabytes
-- *Operator*: daocloud.io
-- *Environment*: Baremetal and virtual machines
-- *Backups*: None, all data can be recreated if necessary.
-
-In [DaoCloud][DaoCloud], we use Docker and Swarm to deploy and run our applications, and we use etcd to save metadata for service discovery.
-
-[DaoCloud]:https://www.daocloud.io
-
-## Branch.io
-
-- *Application*: Kubernetes
-- *Launched*: April 2016
-- *Cluster Size*: Multiple clusters, multiple sizes
-- *Order of Data Size*: 100s of Megabytes
-- *Operator*: branch.io
-- *Environment*: AWS, Kubernetes
-- *Backups*: EBS volume backups
-
-At [Branch][branch], we use kubernetes heavily as our core microservice platform for staging and production.
-
-[branch]: https://branch.io
-
-## Baidu Waimai
-
-- *Application*: SkyDNS, Kubernetes, UDC, CMDB and other distributed systems
-- *Launched*: April. 2016
-- *Cluster Size*: 3 clusters of 5 members
-- *Order of Data Size*: several gigabytes
-- *Operator*: Baidu Waimai Operations Department
-- *Environment*: CentOS 6.5
-- *Backups*: backup scripts
-
-## Salesforce.com
-
-- *Application*: Kubernetes
-- *Launched*: Jan 2017
-- *Cluster Size*: Multiple clusters of 3 members
-- *Order of Data Size*: 100s of Megabytes
-- *Operator*: Salesforce.com (krmayankk@github)
-- *Environment*: BareMetal
-- *Backups*: None, all data can be recreated
-
-## Hosted Graphite
-
-- *Application*: Service discovery, locking, ephemeral application data
-- *Launched*: January 2017
-- *Cluster Size*: 2 clusters of 7 members
-- *Order of Data Size*: Megabytes
-- *Operator*: Hosted Graphite (sre@hostedgraphite.com)
-- *Environment*: Bare Metal
-- *Backups*: None, all data is considered ephemeral.
-
-## Transwarp
-
-- *Application*: Transwarp Data Cloud, Transwarp Operating System, Transwarp Data Hub, Sophon
-- *Launched*: January 2016
-- *Cluster Size*: Multiple clusters, multiple sizes
-- *Order of Data Size*: Megabytes
-- *Operator*: Trasnwarp Operating System
-- *Environment*: Bare Metal, Container
-- *Backups*: backup scripts

CHANGELOG-2.3.md

@@ -1,16 +0,0 @@
-
-
-<hr>
-
-
-## [v2.3.8](https://github.com/etcd-io/etcd/releases/tag/v2.3.8) (2017-02-17)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v2.3.7...v2.3.8).
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-

CHANGELOG-3.0.md

@@ -1,291 +0,0 @@
-
-
-<hr>
-
-
-## [v3.0.16](https://github.com/etcd-io/etcd/releases/tag/v3.0.16) (2016-11-13)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.15...v3.0.16) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.4*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.15](https://github.com/etcd-io/etcd/releases/tag/v3.0.15) (2016-11-11)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.14...v3.0.15) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Fixed
-
-- Fix cancel watch request with wrong range end.
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.14](https://github.com/etcd-io/etcd/releases/tag/v3.0.14) (2016-11-04)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.13...v3.0.14) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Added
-
-- v3 `etcdctl migrate` command now supports `--no-ttl` flag to discard keys on transform.
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.13](https://github.com/etcd-io/etcd/releases/tag/v3.0.13) (2016-10-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.12...v3.0.13) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.12](https://github.com/etcd-io/etcd/releases/tag/v3.0.12) (2016-10-07)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.11...v3.0.12) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.11](https://github.com/etcd-io/etcd/releases/tag/v3.0.11) (2016-10-07)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.10...v3.0.11) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Added
-
-- Server returns previous key-value (optional)
-  - `clientv3.WithPrevKV` option
-  - v3 etcdctl `put,watch,del --prev-kv` flag
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.10](https://github.com/etcd-io/etcd/releases/tag/v3.0.10) (2016-09-23)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.9...v3.0.10) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.9](https://github.com/etcd-io/etcd/releases/tag/v3.0.9) (2016-09-15)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.8...v3.0.9) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Added
-
-- Warn on domain names on listen URLs (v3.2 will reject domain names).
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.8](https://github.com/etcd-io/etcd/releases/tag/v3.0.8) (2016-09-09)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.7...v3.0.8) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Other
-
-- Allow only IP addresses in listen URLs (domain names are rejected).
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.7](https://github.com/etcd-io/etcd/releases/tag/v3.0.7) (2016-08-31)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.6...v3.0.7) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Other
-
-- SRV records only allow A records (RFC 2052).
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.6](https://github.com/etcd-io/etcd/releases/tag/v3.0.6) (2016-08-19)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.5...v3.0.6) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.5](https://github.com/etcd-io/etcd/releases/tag/v3.0.5) (2016-08-19)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.4...v3.0.5) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Other
-
-- SRV records (e.g., infra1.example.com) must match the discovery domain (i.e., example.com) if no custom certificate authority is given.
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.4](https://github.com/etcd-io/etcd/releases/tag/v3.0.4) (2016-07-27)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.3...v3.0.4) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Added
-
-- v2 `etcdctl ls` command now supports `--output=json`.
-- Add /var/lib/etcd directory to etcd official Docker image.
-
-### Other
-
-- v2 auth can now use common name from TLS certificate when `--client-cert-auth` is enabled.
-
-### Go
-
-- Compile with [*Go 1.6.3*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.3](https://github.com/etcd-io/etcd/releases/tag/v3.0.3) (2016-07-15)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.2...v3.0.3) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Other
-
-- Revert Dockerfile to use `CMD`, instead of `ENTRYPOINT`, to support `etcdctl` run.
-  - Docker commands for v3.0.2 won't work without specifying executable binary paths.
-- v3 etcdctl default endpoints are now `127.0.0.1:2379`.
-
-### Go
-
-- Compile with [*Go 1.6.2*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.2](https://github.com/etcd-io/etcd/releases/tag/v3.0.2) (2016-07-08)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.1...v3.0.2) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Other
-
-- Dockerfile uses `ENTRYPOINT`, instead of `CMD`, to run etcd without binary path specified.
-
-### Go
-
-- Compile with [*Go 1.6.2*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.1](https://github.com/etcd-io/etcd/releases/tag/v3.0.1) (2016-07-01)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.0...v3.0.1) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.2*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-
-
-## [v3.0.0](https://github.com/etcd-io/etcd/releases/tag/v3.0.0) (2016-06-30)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v2.3.0...v3.0.0) and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_0.md).**
-
-### Go
-
-- Compile with [*Go 1.6.2*](https://golang.org/doc/devel/release.html#go1.6).
-
-
-<hr>
-

CHANGELOG-3.1.md

@@ -1,578 +0,0 @@
-
-
-Previous change logs can be found at [CHANGELOG-3.0](https://github.com/etcd-io/etcd/blob/master/CHANGELOG-3.0.md).
-
-
-The minimum recommended etcd versions to run in **production** are 3.1.11+, 3.2.26+, and 3.3.11+.
-
-
-<hr>
-
-## [v3.1.21](https://github.com/etcd-io/etcd/releases/tag/v3.1.21) (2019-TBD)
-
-### etcdctl v3
-
-- [Strip out insecure endpoints from DNS SRV records when using discovery](https://github.com/etcd-io/etcd/pull/10443) with etcdctl v2
-- Add [`etcdctl endpoint health --write-out` support](https://github.com/etcd-io/etcd/pull/9540).
-  - Previously, [`etcdctl endpoint health --write-out json` did not work](https://github.com/etcd-io/etcd/issues/9532).
-  - The command output is changed. Previously, if endpoint is unreachable, the command output is
-  "\<endpoint\> is unhealthy: failed to connect: \<error message\>". This change unified the error message, all error types
-  now have the same output "\<endpoint\> is unhealthy: failed to commit proposal: \<error message\>".
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Fix bug where [db_compaction_total_duration_milliseconds metric incorrectly measured duration as 0](https://github.com/etcd-io/etcd/pull/10646).
-
-<hr>
-
-## [v3.1.20](https://github.com/etcd-io/etcd/releases/tag/v3.1.20) (2018-10-10)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.19...v3.1.20) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Improved
-
-- Improve ["became inactive" warning log](https://github.com/etcd-io/etcd/pull/10024), which indicates message send to a peer failed.
-- Improve [read index wait timeout warning log](https://github.com/etcd-io/etcd/pull/10026), which indicates that local node might have slow network.
-- Add [gRPC interceptor for debugging logs](https://github.com/etcd-io/etcd/pull/9990); enable `etcd --debug` flag to see per-request debug information.
-- Add [consistency check in snapshot status](https://github.com/etcd-io/etcd/pull/10109). If consistency check on snapshot file fails, `snapshot status` returns `"snapshot file integrity check failed..."` error.
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Improve [`etcd_network_peer_round_trip_time_seconds`](https://github.com/etcd-io/etcd/pull/10155) Prometheus metric to track leader heartbeats.
-  - Previously, it only samples the TCP connection for snapshot messages.
-- Display all registered [gRPC metrics at start](https://github.com/etcd-io/etcd/pull/10034).
-- Add [`etcd_snap_db_fsync_duration_seconds_count`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_snap_db_save_total_duration_seconds_bucket`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_send_success`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_send_failures`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_send_total_duration_seconds`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_success`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_failures`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_total_duration_seconds`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_server_id`](https://github.com/etcd-io/etcd/pull/9998) Prometheus metric.
-- Add [`etcd_server_health_success`](https://github.com/etcd-io/etcd/pull/10156) Prometheus metric.
-- Add [`etcd_server_health_failures`](https://github.com/etcd-io/etcd/pull/10156) Prometheus metric.
-- Add [`etcd_server_read_indexes_failed_total`](https://github.com/etcd-io/etcd/pull/10094) Prometheus metric.
-
-### client v3
-
-- Fix logic on [release lock key if cancelled](https://github.com/etcd-io/etcd/pull/10153) in `clientv3/concurrency` package.
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.19](https://github.com/etcd-io/etcd/releases/tag/v3.1.19) (2018-07-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.18...v3.1.19) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Improved
-
-- Improve [Raft Read Index timeout warning messages](https://github.com/etcd-io/etcd/pull/9897).
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add [`etcd_server_go_version`](https://github.com/etcd-io/etcd/pull/9957) Prometheus metric.
-- Add [`etcd_server_slow_read_indexes_total`](https://github.com/etcd-io/etcd/pull/9897) Prometheus metric.
-- Add [`etcd_server_quota_backend_bytes`](https://github.com/etcd-io/etcd/pull/9820) Prometheus metric.
-  - Use it with `etcd_mvcc_db_total_size_in_bytes` and `etcd_mvcc_db_total_size_in_use_in_bytes`.
-  - `etcd_server_quota_backend_bytes 2.147483648e+09` means current quota size is 2 GB.
-  - `etcd_mvcc_db_total_size_in_bytes 20480` means current physically allocated DB size is 20 KB.
-  - `etcd_mvcc_db_total_size_in_use_in_bytes 16384` means future DB size if defragment operation is complete.
-  - `etcd_mvcc_db_total_size_in_bytes - etcd_mvcc_db_total_size_in_use_in_bytes` is the number of bytes that can be saved on disk with defragment operation.
-- Add [`etcd_mvcc_db_total_size_in_bytes`](https://github.com/etcd-io/etcd/pull/9819) Prometheus metric.
-  - In addition to [`etcd_debugging_mvcc_db_total_size_in_bytes`](https://github.com/etcd-io/etcd/pull/9819).
-- Add [`etcd_mvcc_db_total_size_in_use_in_bytes`](https://github.com/etcd-io/etcd/pull/9256) Prometheus metric.
-  - Use it with `etcd_mvcc_db_total_size_in_bytes` and `etcd_mvcc_db_total_size_in_use_in_bytes`.
-  - `etcd_server_quota_backend_bytes 2.147483648e+09` means current quota size is 2 GB.
-  - `etcd_mvcc_db_total_size_in_bytes 20480` means current physically allocated DB size is 20 KB.
-  - `etcd_mvcc_db_total_size_in_use_in_bytes 16384` means future DB size if defragment operation is complete.
-  - `etcd_mvcc_db_total_size_in_bytes - etcd_mvcc_db_total_size_in_use_in_bytes` is the number of bytes that can be saved on disk with defragment operation.
-
-### client v3
-
-- Fix [lease keepalive interval updates when response queue is full](https://github.com/etcd-io/etcd/pull/9952).
-  - If `<-chan *clientv3LeaseKeepAliveResponse` from `clientv3.Lease.KeepAlive` was never consumed or channel is full, client was [sending keepalive request every 500ms](https://github.com/etcd-io/etcd/issues/9911) instead of expected rate of every "TTL / 3" duration.
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.18](https://github.com/etcd-io/etcd/releases/tag/v3.1.18) (2018-06-15)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.17...v3.1.18) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add [`etcd_server_version`](https://github.com/etcd-io/etcd/pull/8960) Prometheus metric.
-  - To replace [Kubernetes `etcd-version-monitor`](https://github.com/etcd-io/etcd/issues/8948).
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.17](https://github.com/etcd-io/etcd/releases/tag/v3.1.17) (2018-06-06)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.16...v3.1.17) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Fix [v3 snapshot recovery](https://github.com/etcd-io/etcd/issues/7628).
-  - A follower receives a leader snapshot to be persisted as a `[SNAPSHOT-INDEX].snap.db` file on disk.
-  - Now, server [ensures that the incoming snapshot be persisted on disk before loading it](https://github.com/etcd-io/etcd/pull/7876).
-  - Otherwise, index mismatch happens and triggers server-side panic (e.g. newer WAL entry with outdated snapshot index).
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.16](https://github.com/etcd-io/etcd/releases/tag/v3.1.16) (2018-05-31)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.15...v3.1.16) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Fix [`mvcc` server panic from restore operation](https://github.com/etcd-io/etcd/pull/9775).
-  - Let's assume that a watcher had been requested with a future revision X and sent to node A that became network-partitioned thereafter. Meanwhile, cluster makes progress. Then when the partition gets removed, the leader sends a snapshot to node A. Previously if the snapshot's latest revision is still lower than the watch revision X,  **etcd server panicked** during snapshot restore operation.
-  - Now, this server-side panic has been fixed.
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.15](https://github.com/etcd-io/etcd/releases/tag/v3.1.15) (2018-05-09)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.14...v3.1.15) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Purge old [`*.snap.db` snapshot files](https://github.com/etcd-io/etcd/pull/7967).
-  - Previously, etcd did not respect `--max-snapshots` flag to purge old `*.snap.db` files.
-  - Now, etcd purges old `*.snap.db` files to keep maximum `--max-snapshots` number of files on disk.
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.14](https://github.com/etcd-io/etcd/releases/tag/v3.1.14) (2018-04-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.13...v3.1.14) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add [`etcd_server_is_leader`](https://github.com/etcd-io/etcd/pull/9587) Prometheus metric.
-
-### etcd server
-
-- Add [`--initial-election-tick-advance`](https://github.com/etcd-io/etcd/pull/9591) flag to configure initial election tick fast-forward.
-  - By default, `--initial-election-tick-advance=true`, then local member fast-forwards election ticks to speed up "initial" leader election trigger.
-  - This benefits the case of larger election ticks. For instance, cross datacenter deployment may require longer election timeout of 10-second. If true, local node does not need wait up to 10-second. Instead, forwards its election ticks to 8-second, and have only 2-second left before leader election.
-  - Major assumptions are that: cluster has no active leader thus advancing ticks enables faster leader election. Or cluster already has an established leader, and rejoining follower is likely to receive heartbeats from the leader after tick advance and before election timeout.
-  - However, when network from leader to rejoining follower is congested, and the follower does not receive leader heartbeat within left election ticks, disruptive election has to happen thus affecting cluster availabilities.
-  - Now, this can be disabled by setting `--initial-election-tick-advance=false`.
-  - Disabling this would slow down initial bootstrap process for cross datacenter deployments. Make tradeoffs by configuring `--initial-election-tick-advance` at the cost of slow initial bootstrap.
-  - If single-node, it advances ticks regardless.
-  - Address [disruptive rejoining follower node](https://github.com/etcd-io/etcd/issues/9333).
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.13](https://github.com/etcd-io/etcd/releases/tag/v3.1.13) (2018-03-29)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.12...v3.1.13) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Improved
-
-- Adjust [election timeout on server restart](https://github.com/etcd-io/etcd/pull/9415) to reduce [disruptive rejoining servers](https://github.com/etcd-io/etcd/issues/9333).
-  - Previously, etcd fast-forwards election ticks on server start, with only one tick left for leader election. This is to speed up start phase, without having to wait until all election ticks elapse. Advancing election ticks is useful for cross datacenter deployments with larger election timeouts. However, it was affecting cluster availability if the last tick elapses before leader contacts the restarted node.
-  - Now, when etcd restarts, it adjusts election ticks with more than one tick left, thus more time for leader to prevent disruptive restart.
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add missing [`etcd_network_peer_sent_failures_total` count](https://github.com/etcd-io/etcd/pull/9437).
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.12](https://github.com/etcd-io/etcd/releases/tag/v3.1.12) (2018-03-08)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.11...v3.1.12) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Fix [`mvcc` "unsynced" watcher restore operation](https://github.com/etcd-io/etcd/pull/9297).
-  - "unsynced" watcher is watcher that needs to be in sync with events that have happened.
-  - That is, "unsynced" watcher is the slow watcher that was requested on old revision.
-  - "unsynced" watcher restore operation was not correctly populating its underlying watcher group.
-  - Which possibly causes [missing events from "unsynced" watchers](https://github.com/etcd-io/etcd/issues/9086).
-  - A node gets network partitioned with a watcher on a future revision, and falls behind receiving a leader snapshot after partition gets removed. When applying this snapshot, etcd watch storage moves current synced watchers to unsynced since sync watchers might have become stale during network partition. And reset synced watcher group to restart watcher routines. Previously, there was a bug when moving from synced watcher group to unsynced, thus client would miss events when the watcher was requested to the network-partitioned node.
-
-### Go
-
-- Compile with [*Go 1.8.7*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.11](https://github.com/etcd-io/etcd/releases/tag/v3.1.11) (2017-11-28)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.10...v3.1.11) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- [#8411](https://github.com/etcd-io/etcd/issues/8411),[#8806](https://github.com/etcd-io/etcd/pull/8806) backport "mvcc: sending events after restore"
-- [#8009](https://github.com/etcd-io/etcd/issues/8009),[#8902](https://github.com/etcd-io/etcd/pull/8902) backport coreos/bbolt v1.3.1-coreos.5
-
-### Go
-
-- Compile with [*Go 1.8.5*](https://golang.org/doc/devel/release.html#go1.8).
-
-
-<hr>
-
-
-## [v3.1.10](https://github.com/etcd-io/etcd/releases/tag/v3.1.10) (2017-07-14)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.9...v3.1.10) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Added
-
-- Tag docker images with minor versions.
-  - e.g. `docker pull quay.io/coreos/etcd:v3.1` to fetch latest v3.1 versions.
-
-### Go
-
-- Compile with [*Go 1.8.3*](https://golang.org/doc/devel/release.html#go1.8).
-  - Fix panic on `net/http.CloseNotify`
-
-
-<hr>
-
-
-## [v3.1.9](https://github.com/etcd-io/etcd/releases/tag/v3.1.9) (2017-06-09)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.8...v3.1.9) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Allow v2 snapshot over 512MB.
-
-### Go
-
-- Compile with [*Go 1.7.6*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.8](https://github.com/etcd-io/etcd/releases/tag/v3.1.8) (2017-05-19)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.7...v3.1.8) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.7](https://github.com/etcd-io/etcd/releases/tag/v3.1.7) (2017-04-28)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.6...v3.1.7) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.6](https://github.com/etcd-io/etcd/releases/tag/v3.1.6) (2017-04-19)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.5...v3.1.6) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Fill in Auth API response header.
-- Remove auth check in Status API.
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.5](https://github.com/etcd-io/etcd/releases/tag/v3.1.5) (2017-03-27)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.4...v3.1.5) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd server
-
-- Fix raft memory leak issue.
-- Fix Windows file path issues.
-
-### Other
-
-- Add `/etc/nsswitch.conf` file to alpine-based Docker image.
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.4](https://github.com/etcd-io/etcd/releases/tag/v3.1.4) (2017-03-22)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.3...v3.1.4) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.3](https://github.com/etcd-io/etcd/releases/tag/v3.1.3) (2017-03-10)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.2...v3.1.3) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd gateway
-
-- Fix `etcd gateway` schema handling in DNS discovery.
-- Fix sd_notify behaviors in `gateway`, `grpc-proxy`.
-
-### gRPC Proxy
-
-- Fix sd_notify behaviors in `gateway`, `grpc-proxy`.
-
-### Other
-
-- Use machine default host when advertise URLs are default values(`localhost:2379,2380`) AND if listen URL is `0.0.0.0`.
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.2](https://github.com/etcd-io/etcd/releases/tag/v3.1.2) (2017-02-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.1...v3.1.2) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### etcd gateway
-
-- Fix `etcd gateway` with multiple endpoints.
-
-### Other
-
-- Use IPv4 default host, by default (when IPv4 and IPv6 are available).
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.1](https://github.com/etcd-io/etcd/releases/tag/v3.1.1) (2017-02-17)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.1.0...v3.1.1) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Go
-
-- Compile with [*Go 1.7.5*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-
-
-## [v3.1.0](https://github.com/etcd-io/etcd/releases/tag/v3.1.0) (2017-01-20)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.0.0...v3.1.0) and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.1 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_1.md).**
-
-### Improved
-
-- Faster linearizable reads (implements Raft [read-index](https://github.com/etcd-io/etcd/pull/6212)).
-- v3 authentication API is now stable.
-
-### Breaking Changes
-
-- Deprecated following gRPC metrics in favor of [go-grpc-prometheus](https://github.com/grpc-ecosystem/go-grpc-prometheus).
-  - `etcd_grpc_requests_total`
-  - `etcd_grpc_requests_failed_total`
-  - `etcd_grpc_active_streams`
-  - `etcd_grpc_unary_requests_duration_seconds`
-
-### Dependency
-
-- Upgrade [`github.com/ugorji/go/codec`](https://github.com/ugorji/go) to [**`ugorji/go@9c7f9b7`**](https://github.com/ugorji/go/commit/9c7f9b7a2bc3a520f7c7b30b34b7f85f47fe27b6), and [regenerate v2 `client`](https://github.com/etcd-io/etcd/pull/6945).
-
-### Security, Authentication
-
-See [security doc](https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/security.md) for more details.
-
-- SRV records (e.g., infra1.example.com) must match the discovery domain (i.e., example.com) if no custom certificate authority is given.
-  - `TLSConfig.ServerName` is ignored with user-provided certificates for backwards compatibility; to be deprecated.
-  - For example, `etcd --discovery-srv=example.com` will only authenticate peers/clients when the provided certs have root domain `example.com` as an entry in Subject Alternative Name (SAN) field.
-
-### etcd server
-
-- Automatic leadership transfer when leader steps down.
-- etcd flags
-  - `--strict-reconfig-check` flag is set by default.
-  - Add `--log-output` flag.
-  - Add `--metrics` flag.
-- etcd uses default route IP if advertise URL is not given.
-- Cluster rejects removing members if quorum will be lost.
-- Discovery now has upper limit for waiting on retries.
-- Warn on binding listeners through domain names; to be deprecated.
-- v3.0 and v3.1 with `--auto-compaction-retention=10` run periodic compaction on v3 key-value store for every 10-hour.
-  - Compactor only supports periodic compaction.
-  - Compactor records latest revisions every 5-minute, until it reaches the first compaction period (e.g. 10-hour).
-  - In order to retain key-value history of last compaction period, it uses the last revision that was fetched before compaction period, from the revision records that were collected every 5-minute.
-  - When `--auto-compaction-retention=10`, compactor uses revision 100 for compact revision where revision 100 is the latest revision fetched from 10 hours ago.
-  - If compaction succeeds or requested revision has already been compacted, it resets period timer and starts over with new historical revision records (e.g. restart revision collect and compact for the next 10-hour period).
-  - If compaction fails, it retries in 5 minutes.
-
-### client v3
-
-- Add `SetEndpoints` method; update endpoints at runtime.
-- Add `Sync` method; auto-update endpoints at runtime.
-- Add `Lease TimeToLive` API; fetch lease information.
-- replace Config.Logger field with global logger.
-- Get API responses are sorted in ascending order by default.
-
-### etcdctl v3
-
-- Add `lease timetolive` command.
-- Add `--print-value-only` flag to get command.
-- Add `--dest-prefix` flag to make-mirror command.
-- `get` command responses are sorted in ascending order by default.
-
-### gRPC Proxy
-
-- Experimental gRPC proxy feature.
-
-### Other
-
-- `recipes` now conform to sessions defined in `clientv3/concurrency`.
-- ACI has symlinks to `/usr/local/bin/etcd*`.
-
-### Go
-
-- Compile with [*Go 1.7.4*](https://golang.org/doc/devel/release.html#go1.7).
-
-
-<hr>
-

CHANGELOG-3.4.md

@@ -1,994 +0,0 @@
-
-
-Previous change logs can be found at [CHANGELOG-3.3](https://github.com/etcd-io/etcd/blob/master/CHANGELOG-3.3.md).
-
-
-The minimum recommended etcd versions to run in **production** are 3.2.28+, 3.3.18+, and 3.4.2+.
-
-
-<hr>
-
-
-## v3.4.14 (2020-11-25)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.13...v3.4.14) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### Package `clientv3`
-
-- Fix [auth token invalid after watch reconnects](https://github.com/etcd-io/etcd/pull/12264). Get AuthToken automatically when clientConn is ready.
-
-### etcd server
-
-- [Fix server panic](https://github.com/etcd-io/etcd/pull/12288) when force-new-cluster flag is enabled in a cluster which had learner node.
-
-### Package `netutil`
-
-- Remove [`netutil.DropPort/RecoverPort/SetLatency/RemoveLatency`](https://github.com/etcd-io/etcd/pull/12491).
-  - These are not used anymore. They were only used for older versions of functional testing.
-  - Removed to adhere to best security practices, minimize arbitrary shell invocation.
-
-### `tools/etcd-dump-metrics`
-
-- Implement [input validation to prevent arbitrary shell invocation](https://github.com/etcd-io/etcd/pull/12491).
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.13](https://github.com/etcd-io/etcd/releases/tag/v3.4.13) (2020-8-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.12...v3.4.13) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### Security
-
-- A [log warning](https://github.com/etcd-io/etcd/pull/12242) is added when etcd use any existing directory that has a permission different than 700 on Linux and 777 on Windows.
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.12](https://github.com/etcd-io/etcd/releases/tag/v3.4.12) (2020-08-19)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.11...v3.4.12) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### etcd server
-
-- Fix [server panic in slow writes warnings](https://github.com/etcd-io/etcd/issues/12197).
-  - Fixed via [PR#12238](https://github.com/etcd-io/etcd/pull/12238).
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-
-<hr>
-
-
-
-## [v3.4.11](https://github.com/etcd-io/etcd/releases/tag/v3.4.11) (2020-08-18)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.10...v3.4.11) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### etcd server
-
-- Improve [`runtime.FDUsage` call pattern to reduce objects malloc of Memory Usage and CPU Usage](https://github.com/etcd-io/etcd/pull/11986).
-- Add [`etcd --experimental-watch-progress-notify-interval`](https://github.com/etcd-io/etcd/pull/12216) flag to make watch progress notify interval configurable.
-
-### Package `clientv3`
-
-- Remove [excessive watch cancel logging messages](https://github.com/etcd-io/etcd/pull/12187).
-  - See [kubernetes/kubernetes#93450](https://github.com/kubernetes/kubernetes/issues/93450).
-
-### Package `runtime`
-
-- Optimize [`runtime.FDUsage` by removing unnecessary sorting](https://github.com/etcd-io/etcd/pull/12214).
-
-### Metrics, Monitoring
-
-- Add [`os_fd_used` and `os_fd_limit` to monitor current OS file descriptors](https://github.com/etcd-io/etcd/pull/12214).
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-
-
-<hr>
-
-
-
-
-## [v3.4.10](https://github.com/etcd-io/etcd/releases/tag/v3.4.10) (2020-07-16)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.9...v3.4.10) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### Package `etcd server`
-
-- Add [`--unsafe-no-fsync`](https://github.com/etcd-io/etcd/pull/11946) flag.
-  - Setting the flag disables all uses of fsync, which is unsafe and will cause data loss. This flag makes it possible to run an etcd node for testing and development without placing lots of load on the file system.
-- Add [etcd --auth-token-ttl](https://github.com/etcd-io/etcd/pull/11980) flag to customize `simpleTokenTTL` settings.
-- Improve [runtime.FDUsage objects malloc of Memory Usage and CPU Usage](https://github.com/etcd-io/etcd/pull/11986).
-- Improve [mvcc.watchResponse channel Memory Usage](https://github.com/etcd-io/etcd/pull/11987).
-- Fix [`int64` convert panic in raft logger](https://github.com/etcd-io/etcd/pull/12106).
-  - Fix [kubernetes/kubernetes#91937](https://github.com/kubernetes/kubernetes/issues/91937).
-
-### Breaking Changes
-
-- Changed behavior on [existing dir permission](https://github.com/etcd-io/etcd/pull/11798).
-  - Previously, the permission was not checked on existing data directory and the directory used for automatically generating self-signed certificates for TLS connections with clients. Now a check is added to make sure those directories, if already exist, has a desired permission of 700 on Linux and 777 on Windows.
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.9](https://github.com/etcd-io/etcd/releases/tag/v3.4.9) (2020-05-20)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.8...v3.4.9) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### Package `wal`
-
-- Add [missing CRC checksum check in WAL validate method otherwise causes panic](https://github.com/etcd-io/etcd/pull/11924).
-  - See https://github.com/etcd-io/etcd/issues/11918.
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.8](https://github.com/etcd-io/etcd/releases/tag/v3.4.8) (2020-05-18)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.7...v3.4.8) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### `etcdctl`
-
-- Make sure [save snapshot downloads checksum for integrity checks](https://github.com/etcd-io/etcd/pull/11896).
-
-### Package `clientv3`
-
-- Make sure [save snapshot downloads checksum for integrity checks](https://github.com/etcd-io/etcd/pull/11896).
-
-### etcd server
-
-- Improve logging around snapshot send and receive.
-- [Add log when etcdserver failed to apply command](https://github.com/etcd-io/etcd/pull/11670).
-- [Fix deadlock bug in mvcc](https://github.com/etcd-io/etcd/pull/11817).
-- Fix [inconsistency between WAL and server snapshot](https://github.com/etcd-io/etcd/pull/11888).
-  - Previously, server restore fails if it had crashed after persisting raft hard state but before saving snapshot.
-  - See https://github.com/etcd-io/etcd/issues/10219 for more.
-
-### Package Auth
-
-- [Fix a data corruption bug by saving consistent index](https://github.com/etcd-io/etcd/pull/11652).
-
-### Metrics, Monitoring
-
-- Add [`etcd_debugging_auth_revision`](https://github.com/etcd-io/etcd/commit/f14d2a087f7b0fd6f7980b95b5e0b945109c95f3).
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.7](https://github.com/etcd-io/etcd/releases/tag/v3.4.7) (2020-04-01)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.6...v3.4.7) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### etcd server
-
-- Improve [compaction performance when latest index is greater than 1-million](https://github.com/etcd-io/etcd/pull/11734).
-
-### Package `wal`
-
-- Add [`etcd_wal_write_bytes_total`](https://github.com/etcd-io/etcd/pull/11738).
-
-### Metrics, Monitoring
-
-- Add [`etcd_wal_write_bytes_total`](https://github.com/etcd-io/etcd/pull/11738).
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.6](https://github.com/etcd-io/etcd/releases/tag/v3.4.6) (2020-03-29)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.5...v3.4.6) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-### Package `lease`
-
-- Fix [memory leak in follower nodes](https://github.com/etcd-io/etcd/pull/11731).
-  - https://github.com/etcd-io/etcd/issues/11495
-  - https://github.com/etcd-io/etcd/issues/11730
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.5](https://github.com/etcd-io/etcd/releases/tag/v3.4.5) (2020-03-18)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.4...v3.4.5) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md).**
-
-### etcd server
-
-- Log [`[CLIENT-PORT]/health` check in server side](https://github.com/etcd-io/etcd/pull/11704).
-
-### client v3
-
-- Fix [`"hasleader"` metadata embedding](https://github.com/etcd-io/etcd/pull/11687).
-  - Previously, `clientv3.WithRequireLeader(ctx)` was overwriting existing context keys.
-
-### etcdctl v3
-
-- Fix [`etcdctl member add`](https://github.com/etcd-io/etcd/pull/11638) command to prevent potential timeout.
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-- Add [`etcd_server_client_requests_total` with `"type"` and `"client_api_version"` labels](https://github.com/etcd-io/etcd/pull/11687).
-
-### gRPC Proxy
-
-- Fix [`panic on error`](https://github.com/etcd-io/etcd/pull/11694) for metrics handler.
-
-### Go
-
-- Compile with [*Go 1.12.17*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.4](https://github.com/etcd-io/etcd/releases/tag/v3.4.4) (2020-02-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.3...v3.4.4) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md).**
-
-### etcd server
-
-- Fix [`wait purge file loop during shutdown`](https://github.com/etcd-io/etcd/pull/11308).
-  - Previously, during shutdown etcd could accidentally remove needed wal files, resulting in catastrophic error `etcdserver: open wal error: wal: file not found.` during startup.
-  - Now, etcd makes sure the purge file loop exits before server signals stop of the raft node.
-- [Fix corruption bug in defrag](https://github.com/etcd-io/etcd/pull/11613).
-- Fix [quorum protection logic when promoting a learner](https://github.com/etcd-io/etcd/pull/11640).
-- Improve [peer corruption checker](https://github.com/etcd-io/etcd/pull/11621) to work when peer mTLS is enabled.
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add [`etcd_debugging_mvcc_total_put_size_in_bytes`](https://github.com/etcd-io/etcd/pull/11374) Prometheus metric.
-- Fix bug where [etcd_debugging_mvcc_db_compaction_keys_total is always 0](https://github.com/etcd-io/etcd/pull/11400).
-
-### Auth
-
-- Fix [NoPassword check when adding user through GRPC gateway](https://github.com/etcd-io/etcd/pull/11418) ([issue#11414](https://github.com/etcd-io/etcd/issues/11414))
-- Fix bug where [some auth related messages are logged at wrong level](https://github.com/etcd-io/etcd/pull/11586)
-
-
-<hr>
-
-
-## [v3.4.3](https://github.com/etcd-io/etcd/releases/tag/v3.4.3) (2019-10-24)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.2...v3.4.3) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md).**
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Change [`etcd_cluster_version`](https://github.com/etcd-io/etcd/pull/11254) Prometheus metrics to include only major and minor version.
-
-### Go
-
-- Compile with [*Go 1.12.12*](https://golang.org/doc/devel/release.html#go1.12).
-
-
-<hr>
-
-
-## [v3.4.2](https://github.com/etcd-io/etcd/releases/tag/v3.4.2) (2019-10-11)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.1...v3.4.2) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md).**
-
-### etcdctl v3
-
-- Fix [`etcdctl member add`](https://github.com/etcd-io/etcd/pull/11194) command to prevent potential timeout.
-
-### etcdserver
-
-- Add [`tracing`](https://github.com/etcd-io/etcd/pull/11179) to range, put and compact requests in etcdserver.
-
-### Go
-
-- Compile with [*Go 1.12.9*](https://golang.org/doc/devel/release.html#go1.12) including [*Go 1.12.8*](https://groups.google.com/d/msg/golang-announce/65QixT3tcmg/DrFiG6vvCwAJ) security fixes.
-
-### client v3
-
-- Fix [client balancer failover against multiple endpoints](https://github.com/etcd-io/etcd/pull/11184).
-  - Fix ["kube-apiserver: failover on multi-member etcd cluster fails certificate check on DNS mismatch" (kubernetes#83028)](https://github.com/kubernetes/kubernetes/issues/83028).
-- Fix [IPv6 endpoint parsing in client](https://github.com/etcd-io/etcd/pull/11211).
-  - Fix ["1.16: etcd client does not parse IPv6 addresses correctly when members are joining" (kubernetes#83550)](https://github.com/kubernetes/kubernetes/issues/83550).
-
-
-<hr>
-
-
-## [v3.4.1](https://github.com/etcd-io/etcd/releases/tag/v3.4.1) (2019-09-17)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0...v3.4.1) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md).**
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add [`etcd_debugging_mvcc_current_revision`](https://github.com/etcd-io/etcd/pull/11126) Prometheus metric.
-- Add [`etcd_debugging_mvcc_compact_revision`](https://github.com/etcd-io/etcd/pull/11126) Prometheus metric.
-
-### etcd server
-
-- Fix [secure server logging message](https://github.com/etcd-io/etcd/commit/8b053b0f44c14ac0d9f39b9b78c17c57d47966eb).
-- Remove [redundant `%` characters in file descriptor warning message](https://github.com/etcd-io/etcd/commit/d5f79adc9cea9ec8c93669526464b0aa19ed417b).
-
-### Package `embed`
-
-- Add [`embed.Config.ZapLoggerBuilder`](https://github.com/etcd-io/etcd/pull/11148) to allow creating a custom zap logger.
-
-### Dependency
-
-- Upgrade [`google.golang.org/grpc`](https://github.com/grpc/grpc-go/releases) from [**`v1.23.0`**](https://github.com/grpc/grpc-go/releases/tag/v1.23.0) to [**`v1.23.1`**](https://github.com/grpc/grpc-go/releases/tag/v1.23.1).
-
-### Go
-
-- Compile with [*Go 1.12.9*](https://golang.org/doc/devel/release.html#go1.12) including [*Go 1.12.8*](https://groups.google.com/d/msg/golang-announce/65QixT3tcmg/DrFiG6vvCwAJ) security fixes.
-
-
-<hr>
-
-
-## v3.4.0 (2019-08-30)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.3.0...v3.4.0) and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md) for any breaking changes.
-
-- [v3.4.0](https://github.com/etcd-io/etcd/releases/tag/v3.4.0) (2019-08-30), see [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0-rc.4...v3.4.0).
-- [v3.4.0-rc.4](https://github.com/etcd-io/etcd/releases/tag/v3.4.0-rc.4) (2019-08-29), see [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0-rc.3...v3.4.0-rc.4).
-- [v3.4.0-rc.3](https://github.com/etcd-io/etcd/releases/tag/v3.4.0-rc.3) (2019-08-27), see [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0-rc.2...v3.4.0-rc.3).
-- [v3.4.0-rc.2](https://github.com/etcd-io/etcd/releases/tag/v3.4.0-rc.2) (2019-08-23), see [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0-rc.1...v3.4.0-rc.2).
-- [v3.4.0-rc.1](https://github.com/etcd-io/etcd/releases/tag/v3.4.0-rc.1) (2019-08-15), see [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0-rc.0...v3.4.0-rc.1).
-- [v3.4.0-rc.0](https://github.com/etcd-io/etcd/releases/tag/v3.4.0-rc.0) (2019-08-12), see [code changes](https://github.com/etcd-io/etcd/compare/v3.3.0...v3.4.0-rc.0).
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.4 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_4.md).**
-
-### Documentation
-
-- etcd now has a new website! Please visit https://etcd.io.
-
-### Improved
-
-- Add Raft learner: [etcd#10725](https://github.com/etcd-io/etcd/pull/10725), [etcd#10727](https://github.com/etcd-io/etcd/pull/10727), [etcd#10730](https://github.com/etcd-io/etcd/pull/10730).
-  - User guide: [runtime-configuration document](https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/runtime-configuration.md#add-a-new-member-as-learner).
-  - API change: [API reference document](https://github.com/etcd-io/etcd/blob/master/Documentation/dev-guide/api_reference_v3.md).
-  - More details on implementation: [learner design document](https://github.com/etcd-io/etcd/blob/master/Documentation/learning/design-learner.md) and [implementation task list](https://github.com/etcd-io/etcd/issues/10537).
-- Rewrite [client balancer](https://github.com/etcd-io/etcd/pull/9860) with [new gRPC balancer interface](https://github.com/etcd-io/etcd/issues/9106).
-  - Upgrade [gRPC to v1.23.0](https://github.com/etcd-io/etcd/pull/10911).
-  - Improve [client balancer failover against secure endpoints](https://github.com/etcd-io/etcd/pull/10911).
-    - Fix ["kube-apiserver 1.13.x refuses to work when first etcd-server is not available" (kubernetes#72102)](https://github.com/kubernetes/kubernetes/issues/72102).
-  - Fix [gRPC panic "send on closed channel](https://github.com/etcd-io/etcd/issues/9956).
-  - [The new client balancer](https://github.com/etcd-io/etcd/blob/master/Documentation/learning/design-client.md) uses an asynchronous resolver to pass endpoints to the gRPC dial function. To block until the underlying connection is up, pass `grpc.WithBlock()` to `clientv3.Config.DialOptions`.
-- Add [backoff on watch retries on transient errors](https://github.com/etcd-io/etcd/pull/9840).
-- Add [jitter to watch progress notify](https://github.com/etcd-io/etcd/pull/9278) to prevent [spikes in `etcd_network_client_grpc_sent_bytes_total`](https://github.com/etcd-io/etcd/issues/9246).
-- Improve [read index wait timeout warning log](https://github.com/etcd-io/etcd/pull/10026), which indicates that local node might have slow network.
-- Improve [slow request apply warning log](https://github.com/etcd-io/etcd/pull/9288).
-  - e.g. `read-only range request "key:\"/a\" range_end:\"/b\" " with result "range_response_count:3 size:96" took too long (97.966µs) to execute`.
-  - Redact [request value field](https://github.com/etcd-io/etcd/pull/9822).
-  - Provide [response size](https://github.com/etcd-io/etcd/pull/9826).
-- Improve ["became inactive" warning log](https://github.com/etcd-io/etcd/pull/10024), which indicates message send to a peer failed.
-- Improve [TLS setup error logging](https://github.com/etcd-io/etcd/pull/9518) to help debug [TLS-enabled cluster configuring issues](https://github.com/etcd-io/etcd/issues/9400).
-- Improve [long-running concurrent read transactions under light write workloads](https://github.com/etcd-io/etcd/pull/9296).
-  - Previously, periodic commit on pending writes blocks incoming read transactions, even if there is no pending write.
-  - Now, periodic commit operation does not block concurrent read transactions, thus improves long-running read transaction performance.
-- Make [backend read transactions fully concurrent](https://github.com/etcd-io/etcd/pull/10523).
-  - Previously, ongoing long-running read transactions block writes and future reads.
-  - With this change, write throughput is increased by 70% and P99 write latency is reduced by 90% in the presence of long-running reads.
-- Improve [Raft Read Index timeout warning messages](https://github.com/etcd-io/etcd/pull/9897).
-- Adjust [election timeout on server restart](https://github.com/etcd-io/etcd/pull/9415) to reduce [disruptive rejoining servers](https://github.com/etcd-io/etcd/issues/9333).
-  - Previously, etcd fast-forwards election ticks on server start, with only one tick left for leader election. This is to speed up start phase, without having to wait until all election ticks elapse. Advancing election ticks is useful for cross datacenter deployments with larger election timeouts. However, it was affecting cluster availability if the last tick elapses before leader contacts the restarted node.
-  - Now, when etcd restarts, it adjusts election ticks with more than one tick left, thus more time for leader to prevent disruptive restart.
-- Add [Raft Pre-Vote feature](https://github.com/etcd-io/etcd/pull/9352) to reduce [disruptive rejoining servers](https://github.com/etcd-io/etcd/issues/9333).
-  - For instance, a flaky(or rejoining) member may drop in and out, and start campaign. This member will end up with a higher term, and ignore all incoming messages with lower term. In this case, a new leader eventually need to get elected, thus disruptive to cluster availability. Raft implements Pre-Vote phase to prevent this kind of disruptions. If enabled, Raft runs an additional phase of election to check if pre-candidate can get enough votes to win an election.
-- Adjust [periodic compaction retention window](https://github.com/etcd-io/etcd/pull/9485).
-  - e.g. `etcd --auto-compaction-mode=revision --auto-compaction-retention=1000` automatically `Compact` on `"latest revision" - 1000` every 5-minute (when latest revision is 30000, compact on revision 29000).
-  - e.g. Previously, `etcd --auto-compaction-mode=periodic --auto-compaction-retention=24h` automatically `Compact` with 24-hour retention windown for every 2.4-hour. Now, `Compact` happens for every 1-hour.
-  - e.g. Previously, `etcd --auto-compaction-mode=periodic --auto-compaction-retention=30m` automatically `Compact` with 30-minute retention windown for every 3-minute. Now, `Compact` happens for every 30-minute.
-  - Periodic compactor keeps recording latest revisions for every compaction period when given period is less than 1-hour, or for every 1-hour when given compaction period is greater than 1-hour (e.g. 1-hour when `etcd --auto-compaction-mode=periodic --auto-compaction-retention=24h`).
-  - For every compaction period or 1-hour, compactor uses the last revision that was fetched before compaction period, to discard historical data.
-  - The retention window of compaction period moves for every given compaction period or hour.
-  - For instance, when hourly writes are 100 and `etcd --auto-compaction-mode=periodic --auto-compaction-retention=24h`, `v3.2.x`, `v3.3.0`, `v3.3.1`, and `v3.3.2` compact revision 2400, 2640, and 2880 for every 2.4-hour, while `v3.3.3` *or later* compacts revision 2400, 2500, 2600 for every 1-hour.
-  - Futhermore, when `etcd --auto-compaction-mode=periodic --auto-compaction-retention=30m` and writes per minute are about 1000, `v3.3.0`, `v3.3.1`, and `v3.3.2` compact revision 30000, 33000, and 36000, for every 3-minute, while `v3.3.3` *or later* compacts revision 30000, 60000, and 90000, for every 30-minute.
-- Improve [lease expire/revoke operation performance](https://github.com/etcd-io/etcd/pull/9418), address [lease scalability issue](https://github.com/etcd-io/etcd/issues/9496).
-- Make [Lease `Lookup` non-blocking with concurrent `Grant`/`Revoke`](https://github.com/etcd-io/etcd/pull/9229).
-- Make etcd server return `raft.ErrProposalDropped` on internal Raft proposal drop in [v3 applier](https://github.com/etcd-io/etcd/pull/9549) and [v2 applier](https://github.com/etcd-io/etcd/pull/9558).
-  - e.g. a node is removed from cluster, or [`raftpb.MsgProp` arrives at current leader while there is an ongoing leadership transfer](https://github.com/etcd-io/etcd/issues/8975).
-- Add [`snapshot`](https://github.com/etcd-io/etcd/pull/9118) package for easier snapshot workflow (see [`godoc.org/github.com/etcd/clientv3/snapshot`](https://godoc.org/github.com/etcd-io/etcd/clientv3/snapshot) for more).
-- Improve [functional tester](https://github.com/etcd-io/etcd/tree/master/functional) coverage: [proxy layer to run network fault tests in CI](https://github.com/etcd-io/etcd/pull/9081), [TLS is enabled both for server and client](https://github.com/etcd-io/etcd/pull/9534), [liveness mode](https://github.com/etcd-io/etcd/issues/9230), [shuffle test sequence](https://github.com/etcd-io/etcd/issues/9381), [membership reconfiguration failure cases](https://github.com/etcd-io/etcd/pull/9564), [disastrous quorum loss and snapshot recover from a seed member](https://github.com/etcd-io/etcd/pull/9565), [embedded etcd](https://github.com/etcd-io/etcd/pull/9572).
-- Improve [index compaction blocking](https://github.com/etcd-io/etcd/pull/9511) by using a copy on write clone to avoid holding the lock for the traversal of the entire index.
-- Update [JWT methods](https://github.com/etcd-io/etcd/pull/9883) to allow for use of any supported signature method/algorithm.
-- Add [Lease checkpointing](https://github.com/etcd-io/etcd/pull/9924) to persist remaining TTLs to the consensus log periodically so that long lived leases progress toward expiry in the presence of leader elections and server restarts.
-  - Enabled by experimental flag "--experimental-enable-lease-checkpoint".
-- Add [gRPC interceptor for debugging logs](https://github.com/etcd-io/etcd/pull/9990); enable `etcd --debug` flag to see per-request debug information.
-- Add [consistency check in snapshot status](https://github.com/etcd-io/etcd/pull/10109). If consistency check on snapshot file fails, `snapshot status` returns `"snapshot file integrity check failed..."` error.
-- Add [`Verify` function to perform corruption check on WAL contents](https://github.com/etcd-io/etcd/pull/10603).
-- Improve [heartbeat send failure logging](https://github.com/etcd-io/etcd/pull/10663).
-- Support [users with no password](https://github.com/etcd-io/etcd/pull/9817) for reducing security risk introduced by leaked password. The users can only be authenticated with `CommonName` based auth.
-- Add `etcd --experimental-peer-skip-client-san-verification` to [skip verification of peer client address](https://github.com/etcd-io/etcd/pull/10524).
-- Add `etcd --experimental-compaction-batch-limit` to [sets the maximum revisions deleted in each compaction batch](https://github.com/etcd-io/etcd/pull/11034).
-- Reduced default compaction batch size from 10k revisions to 1k revisions to improve p99 latency during compactions and reduced wait between compactions from 100ms to 10ms.
-
-### Breaking Changes
-
-- Rewrite [client balancer](https://github.com/etcd-io/etcd/pull/9860) with [new gRPC balancer interface](https://github.com/etcd-io/etcd/issues/9106).
-  - Upgrade [gRPC to v1.23.0](https://github.com/etcd-io/etcd/pull/10911).
-  - Improve [client balancer failover against secure endpoints](https://github.com/etcd-io/etcd/pull/10911).
-    - Fix ["kube-apiserver 1.13.x refuses to work when first etcd-server is not available" (kubernetes#72102)](https://github.com/kubernetes/kubernetes/issues/72102).
-  - Fix [gRPC panic "send on closed channel](https://github.com/etcd-io/etcd/issues/9956).
-  - [The new client balancer](https://github.com/etcd-io/etcd/blob/master/Documentation/learning/design-client.md) uses an asynchronous resolver to pass endpoints to the gRPC dial function. To block until the underlying connection is up, pass `grpc.WithBlock()` to `clientv3.Config.DialOptions`.
-- Require [*Go 1.12+*](https://github.com/etcd-io/etcd/pull/10045).
-  - Compile with [*Go 1.12.9*](https://golang.org/doc/devel/release.html#go1.12) including [*Go 1.12.8*](https://groups.google.com/d/msg/golang-announce/65QixT3tcmg/DrFiG6vvCwAJ) security fixes.
-- Migrate dependency management tool from `glide` to [Go module](https://github.com/etcd-io/etcd/pull/10063).
-  - <= 3.3 puts `vendor` directory under `cmd/vendor` directory to [prevent conflicting transitive dependencies](https://github.com/etcd-io/etcd/issues/4913).
-  - 3.4 moves `cmd/vendor` directory to `vendor` at repository root.
-  - Remove recursive symlinks in `cmd` directory.
-  - Now `go get/install/build` on `etcd` packages (e.g. `clientv3`, `tools/benchmark`) enforce builds with etcd `vendor` directory.
-- Deprecated `latest` [release container](https://console.cloud.google.com/gcr/images/etcd-development/GLOBAL/etcd) tag.
-  - **`docker pull gcr.io/etcd-development/etcd:latest` would not be up-to-date**.
-- Deprecated [minor](https://semver.org/) version [release container](https://console.cloud.google.com/gcr/images/etcd-development/GLOBAL/etcd) tags.
-  - `docker pull gcr.io/etcd-development/etcd:v3.3` would still work.
-  - **`docker pull gcr.io/etcd-development/etcd:v3.4` would not work**.
-  - Use **`docker pull gcr.io/etcd-development/etcd:v3.4.x`** instead, with the exact patch version.
-- Deprecated [ACIs from official release](https://github.com/etcd-io/etcd/pull/9059).
-  - [AppC was officially suspended](https://github.com/appc/spec#-disclaimer-), as of late 2016.
-  - [`acbuild`](https://github.com/containers/build#this-project-is-currently-unmaintained) is not maintained anymore.
-  - `*.aci` files are not available from `v3.4` release.
-- Move [`"github.com/coreos/etcd"`](https://github.com/etcd-io/etcd/issues/9965) to [`"github.com/etcd-io/etcd"`](https://github.com/etcd-io/etcd/issues/9965).
-  - Change import path to `"go.etcd.io/etcd"`.
-  - e.g. `import "go.etcd.io/etcd/raft"`.
-- Make [`ETCDCTL_API=3 etcdctl` default](https://github.com/etcd-io/etcd/issues/9600).
-  - Now, `etcdctl set foo bar` must be `ETCDCTL_API=2 etcdctl set foo bar`.
-  - Now, `ETCDCTL_API=3 etcdctl put foo bar` could be just `etcdctl put foo bar`.
-- Make [`etcd --enable-v2=false` default](https://github.com/etcd-io/etcd/pull/10935).
-- Make [`embed.DefaultEnableV2` `false` default](https://github.com/etcd-io/etcd/pull/10935).
-- **Deprecated `etcd --ca-file` flag**. Use [`etcd --trusted-ca-file`](https://github.com/etcd-io/etcd/pull/9470) instead (`etcd --ca-file` flag has been marked deprecated since v2.1).
-- **Deprecated `etcd --peer-ca-file` flag**. Use [`etcd --peer-trusted-ca-file`](https://github.com/etcd-io/etcd/pull/9470) instead (`etcd --peer-ca-file` flag has been marked deprecated since v2.1).
-- **Deprecated `pkg/transport.TLSInfo.CAFile` field**. Use [`pkg/transport.TLSInfo.TrustedCAFile`](https://github.com/etcd-io/etcd/pull/9470) instead (`CAFile` field has been marked deprecated since v2.1).
-- Exit on [empty hosts in advertise URLs](https://github.com/etcd-io/etcd/pull/8786).
-  - Address [advertise client URLs accepts empty hosts](https://github.com/etcd-io/etcd/issues/8379).
-  - e.g. exit with error on `--advertise-client-urls=http://:2379`.
-  - e.g. exit with error on `--initial-advertise-peer-urls=http://:2380`.
-- Exit on [shadowed environment variables](https://github.com/etcd-io/etcd/pull/9382).
-  - Address [error on shadowed environment variables](https://github.com/etcd-io/etcd/issues/8380).
-  - e.g. exit with error on `ETCD_NAME=abc etcd --name=def`.
-  - e.g. exit with error on `ETCD_INITIAL_CLUSTER_TOKEN=abc etcd --initial-cluster-token=def`.
-  - e.g. exit with error on `ETCDCTL_ENDPOINTS=abc.com ETCDCTL_API=3 etcdctl endpoint health --endpoints=def.com`.
-- Change [`etcdserverpb.AuthRoleRevokePermissionRequest/key,range_end` fields type from `string` to `bytes`](https://github.com/etcd-io/etcd/pull/9433).
-- Deprecating `etcd_debugging_mvcc_db_total_size_in_bytes` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_db_total_size_in_bytes`](https://github.com/etcd-io/etcd/pull/9819) instead.
-- Deprecating `etcd_debugging_mvcc_put_total` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_put_total`](https://github.com/etcd-io/etcd/pull/10962) instead.
-- Deprecating `etcd_debugging_mvcc_delete_total` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_delete_total`](https://github.com/etcd-io/etcd/pull/10962) instead.
-- Deprecating `etcd_debugging_mvcc_range_total` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_range_total`](https://github.com/etcd-io/etcd/pull/10968) instead.
-- Deprecating `etcd_debugging_mvcc_txn_total`Prometheus metric  (to be removed in v3.5). Use [`etcd_mvcc_txn_total`](https://github.com/etcd-io/etcd/pull/10968) instead.
-- Rename `etcdserver.ServerConfig.SnapCount` field to `etcdserver.ServerConfig.SnapshotCount`, to be consistent with the flag name `etcd --snapshot-count`.
-- Rename `embed.Config.SnapCount` field to [`embed.Config.SnapshotCount`](https://github.com/etcd-io/etcd/pull/9745), to be consistent with the flag name `etcd --snapshot-count`.
-- Change [`embed.Config.CorsInfo` in `*cors.CORSInfo` type to `embed.Config.CORS` in `map[string]struct{}` type](https://github.com/etcd-io/etcd/pull/9490).
-- Deprecated [`embed.Config.SetupLogging`](https://github.com/etcd-io/etcd/pull/9572).
-  - Now logger is set up automatically based on [`embed.Config.Logger`, `embed.Config.LogOutputs`, `embed.Config.Debug` fields](https://github.com/etcd-io/etcd/pull/9572).
-- Rename [`etcd --log-output` to `etcd --log-outputs`](https://github.com/etcd-io/etcd/pull/9624) to support multiple log outputs.
-  - **`etcd --log-output`** will be deprecated in v3.5.
-- Rename [**`embed.Config.LogOutput`** to **`embed.Config.LogOutputs`**](https://github.com/etcd-io/etcd/pull/9624) to support multiple log outputs.
-- Change [**`embed.Config.LogOutputs`** type from `string` to `[]string`](https://github.com/etcd-io/etcd/pull/9579) to support multiple log outputs.
-  - Now that `etcd --log-outputs` accepts multiple writers, etcd configuration YAML file `log-outputs` field must be changed to `[]string` type.
-  - Previously, `etcd --config-file etcd.config.yaml` can have `log-outputs: default` field, now must be `log-outputs: [default]`.
-- Deprecating [`etcd --debug`](https://github.com/etcd-io/etcd/pull/10947) flag. Use `etcd --log-level=debug` flag instead.
-  - v3.5 will deprecate `etcd --debug` flag in favor of `etcd --log-level=debug`.
-- Change v3 `etcdctl snapshot` exit codes with [`snapshot` package](https://github.com/etcd-io/etcd/pull/9118/commits/df689f4280e1cce4b9d61300be13ca604d41670a).
-  - Exit on error with exit code 1 (no more exit code 5 or 6 on `snapshot save/restore` commands).
-- Deprecated [`grpc.ErrClientConnClosing`](https://github.com/etcd-io/etcd/pull/10981).
-  - `clientv3` and `proxy/grpcproxy` now does not return `grpc.ErrClientConnClosing`.
-  - `grpc.ErrClientConnClosing` has been [deprecated in gRPC >= 1.10](https://github.com/grpc/grpc-go/pull/1854).
-  - Use `clientv3.IsConnCanceled(error)` or `google.golang.org/grpc/status.FromError(error)` instead.
-- Deprecated [gRPC gateway](https://github.com/grpc-ecosystem/grpc-gateway) endpoint `/v3beta` with [`/v3`](https://github.com/etcd-io/etcd/pull/9298).
-  - Deprecated [`/v3alpha`](https://github.com/etcd-io/etcd/pull/9298).
-  - To deprecate [`/v3beta`](https://github.com/etcd-io/etcd/issues/9189) in v3.5.
-  - In v3.4, `curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` still works as a fallback to `curl -L http://localhost:2379/v3/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'`, but `curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` won't work in v3.5. Use `curl -L http://localhost:2379/v3/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` instead.
-- Change [`wal` package function signatures](https://github.com/etcd-io/etcd/pull/9572) to support [structured logger and logging to file](https://github.com/etcd-io/etcd/issues/9438) in server-side.
-  - Previously, `Open(dirpath string, snap walpb.Snapshot) (*WAL, error)`, now `Open(lg *zap.Logger, dirpath string, snap walpb.Snapshot) (*WAL, error)`.
-  - Previously, `OpenForRead(dirpath string, snap walpb.Snapshot) (*WAL, error)`, now `OpenForRead(lg *zap.Logger, dirpath string, snap walpb.Snapshot) (*WAL, error)`.
-  - Previously, `Repair(dirpath string) bool`, now `Repair(lg *zap.Logger, dirpath string) bool`.
-  - Previously, `Create(dirpath string, metadata []byte) (*WAL, error)`, now `Create(lg *zap.Logger, dirpath string, metadata []byte) (*WAL, error)`.
-- Remove [`pkg/cors` package](https://github.com/etcd-io/etcd/pull/9490).
-- Move internal packages to `etcdserver`.
-  - `"github.com/coreos/etcd/alarm"` to `"go.etcd.io/etcd/etcdserver/api/v3alarm"`.
-  - `"github.com/coreos/etcd/compactor"` to `"go.etcd.io/etcd/etcdserver/api/v3compactor"`.
-  - `"github.com/coreos/etcd/discovery"` to `"go.etcd.io/etcd/etcdserver/api/v2discovery"`.
-  - `"github.com/coreos/etcd/etcdserver/auth"` to `"go.etcd.io/etcd/etcdserver/api/v2auth"`.
-  - `"github.com/coreos/etcd/etcdserver/membership"` to `"go.etcd.io/etcd/etcdserver/api/membership"`.
-  - `"github.com/coreos/etcd/etcdserver/stats"` to `"go.etcd.io/etcd/etcdserver/api/v2stats"`.
-  - `"github.com/coreos/etcd/error"` to `"go.etcd.io/etcd/etcdserver/api/v2error"`.
-  - `"github.com/coreos/etcd/rafthttp"` to `"go.etcd.io/etcd/etcdserver/api/rafthttp"`.
-  - `"github.com/coreos/etcd/snap"` to `"go.etcd.io/etcd/etcdserver/api/snap"`.
-  - `"github.com/coreos/etcd/store"` to `"go.etcd.io/etcd/etcdserver/api/v2store"`.
-- Change [snapshot file permissions](https://github.com/etcd-io/etcd/pull/9977): On Linux, the snapshot file changes from readable by all (mode 0644) to readable by the user only (mode 0600).
-- Change [`pkg/adt.IntervalTree` from `struct` to `interface`](https://github.com/etcd-io/etcd/pull/10959).
-  - See [`pkg/adt` README](https://github.com/etcd-io/etcd/tree/master/pkg/adt) and [`pkg/adt` godoc](https://godoc.org/go.etcd.io/etcd/pkg/adt).
-- Release branch `/version` defines version `3.4.x-pre`, instead of `3.4.y+git`.
-  - Use `3.4.5-pre`, instead of `3.4.4+git`.
-
-### Dependency
-
-- Upgrade [`github.com/coreos/bbolt`](https://github.com/etcd-io/bbolt/releases) from [**`v1.3.1-coreos.6`**](https://github.com/etcd-io/bbolt/releases/tag/v1.3.1-coreos.6) to [`go.etcd.io/bbolt`](https://github.com/etcd-io/bbolt/releases) [**`v1.3.3`**](https://github.com/etcd-io/bbolt/releases/tag/v1.3.3).
-- Upgrade [`google.golang.org/grpc`](https://github.com/grpc/grpc-go/releases) from [**`v1.7.5`**](https://github.com/grpc/grpc-go/releases/tag/v1.7.5) to [**`v1.23.0`**](https://github.com/grpc/grpc-go/releases/tag/v1.23.0).
-- Migrate [`github.com/ugorji/go/codec`](https://github.com/ugorji/go/releases) to [**`github.com/json-iterator/go`**](https://github.com/json-iterator/go), to [regenerate v2 `client`](https://github.com/etcd-io/etcd/pull/9494) (See [#10667](https://github.com/etcd-io/etcd/pull/10667) for more).
-- Migrate [`github.com/ghodss/yaml`](https://github.com/ghodss/yaml/releases) to [**`sigs.k8s.io/yaml`**](https://github.com/kubernetes-sigs/yaml) (See [#10687](https://github.com/etcd-io/etcd/pull/10687) for more).
-- Upgrade [`golang.org/x/crypto`](https://github.com/golang/crypto) from [**`crypto@9419663f5`**](https://github.com/golang/crypto/commit/9419663f5a44be8b34ca85f08abc5fe1be11f8a3) to [**`crypto@0709b304e793`**](https://github.com/golang/crypto/commit/0709b304e793a5edb4a2c0145f281ecdc20838a4).
-- Upgrade [`golang.org/x/net`](https://github.com/golang/net) from [**`net@66aacef3d`**](https://github.com/golang/net/commit/66aacef3dd8a676686c7ae3716979581e8b03c47) to [**`net@adae6a3d119a`**](https://github.com/golang/net/commit/adae6a3d119ae4890b46832a2e88a95adc62b8e7).
-- Upgrade [`golang.org/x/sys`](https://github.com/golang/sys) from [**`sys@ebfc5b463`**](https://github.com/golang/sys/commit/ebfc5b4631820b793c9010c87fd8fef0f39eb082) to [**`sys@c7b8b68b1456`**](https://github.com/golang/sys/commit/c7b8b68b14567162c6602a7c5659ee0f26417c18).
-- Upgrade [`golang.org/x/text`](https://github.com/golang/text) from [**`text@b19bf474d`**](https://github.com/golang/text/commit/b19bf474d317b857955b12035d2c5acb57ce8b01) to [**`v0.3.0`**](https://github.com/golang/text/releases/tag/v0.3.0).
-- Upgrade [`golang.org/x/time`](https://github.com/golang/time) from [**`time@c06e80d93`**](https://github.com/golang/time/commit/c06e80d9300e4443158a03817b8a8cb37d230320) to [**`time@fbb02b229`**](https://github.com/golang/time/commit/fbb02b2291d28baffd63558aa44b4b56f178d650).
-- Upgrade [`github.com/golang/protobuf`](https://github.com/golang/protobuf/releases) from [**`golang/protobuf@1e59b77b5`**](https://github.com/golang/protobuf/commit/1e59b77b52bf8e4b449a57e6f79f21226d571845) to [**`v1.3.2`**](https://github.com/golang/protobuf/releases/tag/v1.3.2).
-- Upgrade [`gopkg.in/yaml.v2`](https://github.com/go-yaml/yaml/releases) from [**`yaml@cd8b52f82`**](https://github.com/go-yaml/yaml/commit/cd8b52f8269e0feb286dfeef29f8fe4d5b397e0b) to [**`yaml@5420a8b67`**](https://github.com/go-yaml/yaml/commit/5420a8b6744d3b0345ab293f6fcba19c978f1183).
-- Upgrade [`github.com/dgrijalva/jwt-go`](https://github.com/dgrijalva/jwt-go/releases) from [**`v3.0.0`**](https://github.com/dgrijalva/jwt-go/releases/tag/v3.0.0) to [**`v3.2.0`**](https://github.com/dgrijalva/jwt-go/releases/tag/v3.2.0).
-- Upgrade [`github.com/soheilhy/cmux`](https://github.com/soheilhy/cmux/releases) from [**`v0.1.3`**](https://github.com/soheilhy/cmux/releases/tag/v0.1.3) to [**`v0.1.4`**](https://github.com/soheilhy/cmux/releases/tag/v0.1.4).
-- Upgrade [`github.com/google/btree`](https://github.com/google/btree/releases) from [**`google/btree@925471ac9`**](https://github.com/google/btree/commit/925471ac9e2131377a91e1595defec898166fe49) to [**`v1.0.0`**](https://github.com/google/btree/releases/tag/v1.0.0).
-- Upgrade [`github.com/spf13/cobra`](https://github.com/spf13/cobra/releases) from [**`spf13/cobra@1c44ec8d3`**](https://github.com/spf13/cobra/commit/1c44ec8d3f1552cac48999f9306da23c4d8a288b) to [**`v0.0.3`**](https://github.com/spf13/cobra/releases/tag/v0.0.3).
-- Upgrade [`github.com/spf13/pflag`](https://github.com/spf13/pflag/releases) from [**`v1.0.0`**](https://github.com/spf13/pflag/releases/tag/v1.0.0) to [**`spf13/pflag@1ce0cc6db`**](https://github.com/spf13/pflag/commit/1ce0cc6db4029d97571db82f85092fccedb572ce).
-- Upgrade [`github.com/coreos/go-systemd`](https://github.com/coreos/go-systemd/releases) from [**`v15`**](https://github.com/coreos/go-systemd/releases/tag/v15) to [**`v17`**](https://github.com/coreos/go-systemd/releases/tag/v17).
-- Upgrade [`github.com/prometheus/client_golang`](https://github.com/prometheus/client_golang/releases) from [**``prometheus/client_golang@5cec1d042``**](https://github.com/prometheus/client_golang/commit/5cec1d0429b02e4323e042eb04dafdb079ddf568) to [**`v1.0.0`**](https://github.com/prometheus/client_golang/releases/tag/v1.0.0).
-- Upgrade [`github.com/grpc-ecosystem/go-grpc-prometheus`](https://github.com/grpc-ecosystem/go-grpc-prometheus/releases) from [**``grpc-ecosystem/go-grpc-prometheus@0dafe0d49``**](https://github.com/grpc-ecosystem/go-grpc-prometheus/commit/0dafe0d496ea71181bf2dd039e7e3f44b6bd11a7) to [**`v1.2.0`**](https://github.com/grpc-ecosystem/go-grpc-prometheus/releases/tag/v1.2.0).
-- Upgrade [`github.com/grpc-ecosystem/grpc-gateway`](https://github.com/grpc-ecosystem/grpc-gateway/releases) from [**`v1.3.1`**](https://github.com/grpc-ecosystem/grpc-gateway/releases/tag/v1.3.1) to [**`v1.4.1`**](https://github.com/grpc-ecosystem/grpc-gateway/releases/tag/v1.4.1).
-- Migrate [`github.com/kr/pty`](https://github.com/kr/pty/releases) to [**`github.com/creack/pty`**](https://github.com/creack/pty/releases/tag/v1.1.7), as the later has replaced the original module.
-- Upgrade [`github.com/gogo/protobuf`](https://github.com/gogo/protobuf/releases) from [**`v1.0.0`**](https://github.com/gogo/protobuf/releases/tag/v1.0.0) to [**`v1.2.1`**](https://github.com/gogo/protobuf/releases/tag/v1.2.1).
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Add [`etcd_snap_db_fsync_duration_seconds_count`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_snap_db_save_total_duration_seconds_bucket`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_send_success`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_send_failures`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_send_total_duration_seconds`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_success`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_failures`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_total_duration_seconds`](https://github.com/etcd-io/etcd/pull/9997) Prometheus metric.
-- Add [`etcd_network_active_peers`](https://github.com/etcd-io/etcd/pull/9762) Prometheus metric.
-  - Let's say `"7339c4e5e833c029"` server `/metrics` returns `etcd_network_active_peers{Local="7339c4e5e833c029",Remote="729934363faa4a24"} 1` and `etcd_network_active_peers{Local="7339c4e5e833c029",Remote="b548c2511513015"} 1`. This indicates that the local node `"7339c4e5e833c029"` currently has two active remote peers `"729934363faa4a24"` and `"b548c2511513015"` in a 3-node cluster. If the node `"b548c2511513015"` is down, the local node `"7339c4e5e833c029"` will show `etcd_network_active_peers{Local="7339c4e5e833c029",Remote="729934363faa4a24"} 1` and `etcd_network_active_peers{Local="7339c4e5e833c029",Remote="b548c2511513015"} 0`.
-- Add [`etcd_network_disconnected_peers_total`](https://github.com/etcd-io/etcd/pull/9762) Prometheus metric.
-  - If a remote peer `"b548c2511513015"` is down, the local node `"7339c4e5e833c029"` server `/metrics` would return `etcd_network_disconnected_peers_total{Local="7339c4e5e833c029",Remote="b548c2511513015"} 1`, while active peer metrics will show `etcd_network_active_peers{Local="7339c4e5e833c029",Remote="729934363faa4a24"} 1` and `etcd_network_active_peers{Local="7339c4e5e833c029",Remote="b548c2511513015"} 0`.
-- Add [`etcd_network_server_stream_failures_total`](https://github.com/etcd-io/etcd/pull/9760) Prometheus metric.
-  - e.g. `etcd_network_server_stream_failures_total{API="lease-keepalive",Type="receive"} 1`
-  - e.g. `etcd_network_server_stream_failures_total{API="watch",Type="receive"} 1`
-- Improve [`etcd_network_peer_round_trip_time_seconds`](https://github.com/etcd-io/etcd/pull/10155) Prometheus metric to track leader heartbeats.
-  - Previously, it only samples the TCP connection for snapshot messages.
-- Increase [`etcd_network_peer_round_trip_time_seconds`](https://github.com/etcd-io/etcd/pull/9762) Prometheus metric histogram upper-bound.
-  - Previously, highest bucket only collects requests taking 0.8192 seconds or more.
-  - Now, highest buckets collect 0.8192 seconds, 1.6384 seconds, and 3.2768 seconds or more.
-- Add [`etcd_server_is_leader`](https://github.com/etcd-io/etcd/pull/9587) Prometheus metric.
-- Add [`etcd_server_id`](https://github.com/etcd-io/etcd/pull/9998) Prometheus metric.
-- Add [`etcd_cluster_version`](https://github.com/etcd-io/etcd/pull/10257) Prometheus metric.
-- Add [`etcd_server_version`](https://github.com/etcd-io/etcd/pull/8960) Prometheus metric.
-  - To replace [Kubernetes `etcd-version-monitor`](https://github.com/etcd-io/etcd/issues/8948).
-- Add [`etcd_server_go_version`](https://github.com/etcd-io/etcd/pull/9957) Prometheus metric.
-- Add [`etcd_server_health_success`](https://github.com/etcd-io/etcd/pull/10156) Prometheus metric.
-- Add [`etcd_server_health_failures`](https://github.com/etcd-io/etcd/pull/10156) Prometheus metric.
-- Add [`etcd_server_read_indexes_failed_total`](https://github.com/etcd-io/etcd/pull/10094) Prometheus metric.
-- Add [`etcd_server_heartbeat_send_failures_total`](https://github.com/etcd-io/etcd/pull/9761) Prometheus metric.
-- Add [`etcd_server_slow_apply_total`](https://github.com/etcd-io/etcd/pull/9761) Prometheus metric.
-- Add [`etcd_server_slow_read_indexes_total`](https://github.com/etcd-io/etcd/pull/9897) Prometheus metric.
-- Add [`etcd_server_quota_backend_bytes`](https://github.com/etcd-io/etcd/pull/9820) Prometheus metric.
-  - Use it with `etcd_mvcc_db_total_size_in_bytes` and `etcd_mvcc_db_total_size_in_use_in_bytes`.
-  - `etcd_server_quota_backend_bytes 2.147483648e+09` means current quota size is 2 GB.
-  - `etcd_mvcc_db_total_size_in_bytes 20480` means current physically allocated DB size is 20 KB.
-  - `etcd_mvcc_db_total_size_in_use_in_bytes 16384` means future DB size if defragment operation is complete.
-  - `etcd_mvcc_db_total_size_in_bytes - etcd_mvcc_db_total_size_in_use_in_bytes` is the number of bytes that can be saved on disk with defragment operation.
-- Add [`etcd_mvcc_db_total_size_in_use_in_bytes`](https://github.com/etcd-io/etcd/pull/9256) Prometheus metric.
-  - Use it with `etcd_mvcc_db_total_size_in_bytes` and `etcd_mvcc_db_total_size_in_use_in_bytes`.
-  - `etcd_server_quota_backend_bytes 2.147483648e+09` means current quota size is 2 GB.
-  - `etcd_mvcc_db_total_size_in_bytes 20480` means current physically allocated DB size is 20 KB.
-  - `etcd_mvcc_db_total_size_in_use_in_bytes 16384` means future DB size if defragment operation is complete.
-  - `etcd_mvcc_db_total_size_in_bytes - etcd_mvcc_db_total_size_in_use_in_bytes` is the number of bytes that can be saved on disk with defragment operation.
-- Add [`etcd_mvcc_db_open_read_transactions`](https://github.com/etcd-io/etcd/pull/10523/commits/ad80752715aaed449629369687c5fd30eb1bda76) Prometheus metric.
-- Add [`etcd_snap_fsync_duration_seconds`](https://github.com/etcd-io/etcd/pull/9762) Prometheus metric.
-- Add [`etcd_disk_backend_defrag_duration_seconds`](https://github.com/etcd-io/etcd/pull/9761) Prometheus metric.
-- Add [`etcd_mvcc_hash_duration_seconds`](https://github.com/etcd-io/etcd/pull/9761) Prometheus metric.
-- Add [`etcd_mvcc_hash_rev_duration_seconds`](https://github.com/etcd-io/etcd/pull/9761) Prometheus metric.
-- Add [`etcd_debugging_disk_backend_commit_rebalance_duration_seconds`](https://github.com/etcd-io/etcd/pull/9834) Prometheus metric.
-- Add [`etcd_debugging_disk_backend_commit_spill_duration_seconds`](https://github.com/etcd-io/etcd/pull/9834) Prometheus metric.
-- Add [`etcd_debugging_disk_backend_commit_write_duration_seconds`](https://github.com/etcd-io/etcd/pull/9834) Prometheus metric.
-- Add [`etcd_debugging_lease_granted_total`](https://github.com/etcd-io/etcd/pull/9778) Prometheus metric.
-- Add [`etcd_debugging_lease_revoked_total`](https://github.com/etcd-io/etcd/pull/9778) Prometheus metric.
-- Add [`etcd_debugging_lease_renewed_total`](https://github.com/etcd-io/etcd/pull/9778) Prometheus metric.
-- Add [`etcd_debugging_lease_ttl_total`](https://github.com/etcd-io/etcd/pull/9778) Prometheus metric.
-- Add [`etcd_network_snapshot_send_inflights_total`](https://github.com/etcd-io/etcd/pull/11009) Prometheus metric.
-- Add [`etcd_network_snapshot_receive_inflights_total`](https://github.com/etcd-io/etcd/pull/11009) Prometheus metric.
-- Add [`etcd_server_snapshot_apply_in_progress_total`](https://github.com/etcd-io/etcd/pull/11009) Prometheus metric.
-- Add [`etcd_server_is_learner`](https://github.com/etcd-io/etcd/pull/10731) Prometheus metric.
-- Add [`etcd_server_learner_promote_failures`](https://github.com/etcd-io/etcd/pull/10731) Prometheus metric.
-- Add [`etcd_server_learner_promote_successes`](https://github.com/etcd-io/etcd/pull/10731) Prometheus metric.
-- Increase [`etcd_debugging_mvcc_index_compaction_pause_duration_milliseconds`](https://github.com/etcd-io/etcd/pull/9762) Prometheus metric histogram upper-bound.
-  - Previously, highest bucket only collects requests taking 1.024 seconds or more.
-  - Now, highest buckets collect 1.024 seconds, 2.048 seconds, and 4.096 seconds or more.
-- Fix missing [`etcd_network_peer_sent_failures_total`](https://github.com/etcd-io/etcd/pull/9437) Prometheus metric count.
-- Fix [`etcd_debugging_server_lease_expired_total`](https://github.com/etcd-io/etcd/pull/9557) Prometheus metric.
-- Fix [race conditions in v2 server stat collecting](https://github.com/etcd-io/etcd/pull/9562).
-- Change [gRPC proxy to expose etcd server endpoint /metrics](https://github.com/etcd-io/etcd/pull/10618).
-  - The metrics that were exposed via the proxy were not etcd server members but instead the proxy itself.
-- Fix bug where [db_compaction_total_duration_milliseconds metric incorrectly measured duration as 0](https://github.com/etcd-io/etcd/pull/10646).
-- Deprecating `etcd_debugging_mvcc_db_total_size_in_bytes` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_db_total_size_in_bytes`](https://github.com/etcd-io/etcd/pull/9819) instead.
-- Deprecating `etcd_debugging_mvcc_put_total` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_put_total`](https://github.com/etcd-io/etcd/pull/10962) instead.
-- Deprecating `etcd_debugging_mvcc_delete_total` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_delete_total`](https://github.com/etcd-io/etcd/pull/10962) instead.
-- Deprecating `etcd_debugging_mvcc_range_total` Prometheus metric (to be removed in v3.5). Use [`etcd_mvcc_range_total`](https://github.com/etcd-io/etcd/pull/10968) instead.
-- Deprecating `etcd_debugging_mvcc_txn_total`Prometheus metric  (to be removed in v3.5). Use [`etcd_mvcc_txn_total`](https://github.com/etcd-io/etcd/pull/10968) instead.
-
-### Security, Authentication
-
-See [security doc](https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/security.md) for more details.
-
-- Support TLS cipher suite whitelisting.
-  - To block [weak cipher suites](https://github.com/etcd-io/etcd/issues/8320).
-  - TLS handshake fails when client hello is requested with invalid cipher suites.
-  - Add [`etcd --cipher-suites`](https://github.com/etcd-io/etcd/pull/9801) flag.
-  - If empty, Go auto-populates the list.
-- Add [`etcd --host-whitelist`](https://github.com/etcd-io/etcd/pull/9372) flag, [`etcdserver.Config.HostWhitelist`](https://github.com/etcd-io/etcd/pull/9372), and [`embed.Config.HostWhitelist`](https://github.com/etcd-io/etcd/pull/9372), to prevent ["DNS Rebinding"](https://en.wikipedia.org/wiki/DNS_rebinding) attack.
-  - Any website can simply create an authorized DNS name, and direct DNS to `"localhost"` (or any other address). Then, all HTTP endpoints of etcd server listening on `"localhost"` becomes accessible, thus vulnerable to [DNS rebinding attacks (CVE-2018-5702)](https://bugs.chromium.org/p/project-zero/issues/detail?id=1447#c2).
-  - Client origin enforce policy works as follow:
-    - If client connection is secure via HTTPS, allow any hostnames..
-    - If client connection is not secure and `"HostWhitelist"` is not empty, only allow HTTP requests whose Host field is listed in whitelist.
-  - By default, `"HostWhitelist"` is `"*"`, which means insecure server allows all client HTTP requests.
-  - Note that the client origin policy is enforced whether authentication is enabled or not, for tighter controls.
-  - When specifying hostnames, loopback addresses are not added automatically. To allow loopback interfaces, add them to whitelist manually (e.g. `"localhost"`, `"127.0.0.1"`, etc.).
-  - e.g. `etcd --host-whitelist example.com`, then the server will reject all HTTP requests whose Host field is not `example.com` (also rejects requests to `"localhost"`).
-- Support [`etcd --cors`](https://github.com/etcd-io/etcd/pull/9490) in v3 HTTP requests (gRPC gateway).
-- Support [`ttl` field for `etcd` Authentication JWT token](https://github.com/etcd-io/etcd/pull/8302).
-  - e.g. `etcd --auth-token jwt,pub-key=<pub key path>,priv-key=<priv key path>,sign-method=<sign method>,ttl=5m`.
-- Allow empty token provider in [`etcdserver.ServerConfig.AuthToken`](https://github.com/etcd-io/etcd/pull/9369).
-- Fix [TLS reload](https://github.com/etcd-io/etcd/pull/9570) when [certificate SAN field only includes IP addresses but no domain names](https://github.com/etcd-io/etcd/issues/9541).
-  - In Go, server calls `(*tls.Config).GetCertificate` for TLS reload if and only if server's `(*tls.Config).Certificates` field is not empty, or `(*tls.ClientHelloInfo).ServerName` is not empty with a valid SNI from the client. Previously, etcd always populates `(*tls.Config).Certificates` on the initial client TLS handshake, as non-empty. Thus, client was always expected to supply a matching SNI in order to pass the TLS verification and to trigger `(*tls.Config).GetCertificate` to reload TLS assets.
-  - However, a certificate whose SAN field does [not include any domain names but only IP addresses](https://github.com/etcd-io/etcd/issues/9541) would request `*tls.ClientHelloInfo` with an empty `ServerName` field, thus failing to trigger the TLS reload on initial TLS handshake; this becomes a problem when expired certificates need to be replaced online.
-  - Now, `(*tls.Config).Certificates` is created empty on initial TLS client handshake, first to trigger `(*tls.Config).GetCertificate`, and then to populate rest of the certificates on every new TLS connection, even when client SNI is empty (e.g. cert only includes IPs).
-
-### etcd server
-
-- Add [`rpctypes.ErrLeaderChanged`](https://github.com/etcd-io/etcd/pull/10094).
-  - Now linearizable requests with read index would fail fast when there is a leadership change, instead of waiting until context timeout.
-- Add [`etcd --initial-election-tick-advance`](https://github.com/etcd-io/etcd/pull/9591) flag to configure initial election tick fast-forward.
-  - By default, `etcd --initial-election-tick-advance=true`, then local member fast-forwards election ticks to speed up "initial" leader election trigger.
-  - This benefits the case of larger election ticks. For instance, cross datacenter deployment may require longer election timeout of 10-second. If true, local node does not need wait up to 10-second. Instead, forwards its election ticks to 8-second, and have only 2-second left before leader election.
-  - Major assumptions are that: cluster has no active leader thus advancing ticks enables faster leader election. Or cluster already has an established leader, and rejoining follower is likely to receive heartbeats from the leader after tick advance and before election timeout.
-  - However, when network from leader to rejoining follower is congested, and the follower does not receive leader heartbeat within left election ticks, disruptive election has to happen thus affecting cluster availabilities.
-  - Now, this can be disabled by setting `etcd --initial-election-tick-advance=false`.
-  - Disabling this would slow down initial bootstrap process for cross datacenter deployments. Make tradeoffs by configuring `etcd --initial-election-tick-advance` at the cost of slow initial bootstrap.
-  - If single-node, it advances ticks regardless.
-  - Address [disruptive rejoining follower node](https://github.com/etcd-io/etcd/issues/9333).
-- Add [`etcd --pre-vote`](https://github.com/etcd-io/etcd/pull/9352) flag to enable to run an additional Raft election phase.
-  - For instance, a flaky(or rejoining) member may drop in and out, and start campaign. This member will end up with a higher term, and ignore all incoming messages with lower term. In this case, a new leader eventually need to get elected, thus disruptive to cluster availability. Raft implements Pre-Vote phase to prevent this kind of disruptions. If enabled, Raft runs an additional phase of election to check if pre-candidate can get enough votes to win an election.
-  - `etcd --pre-vote=false` by default.
-  - v3.5 will enable `etcd --pre-vote=true` by default.
-- Add `etcd --experimental-compaction-batch-limit` to [sets the maximum revisions deleted in each compaction batch](https://github.com/etcd-io/etcd/pull/11034).
-- Reduced default compaction batch size from 10k revisions to 1k revisions to improve p99 latency during compactions and reduced wait between compactions from 100ms to 10ms.
-- Add [`etcd --discovery-srv-name`](https://github.com/etcd-io/etcd/pull/8690) flag to support custom DNS SRV name with discovery.
-  - If not given, etcd queries `_etcd-server-ssl._tcp.[YOUR_HOST]` and `_etcd-server._tcp.[YOUR_HOST]`.
-  - If `etcd --discovery-srv-name="foo"`, then query `_etcd-server-ssl-foo._tcp.[YOUR_HOST]` and `_etcd-server-foo._tcp.[YOUR_HOST]`.
-  - Useful for operating multiple etcd clusters under the same domain.
-- Support TLS cipher suite whitelisting.
-  - To block [weak cipher suites](https://github.com/etcd-io/etcd/issues/8320).
-  - TLS handshake fails when client hello is requested with invalid cipher suites.
-  - Add [`etcd --cipher-suites`](https://github.com/etcd-io/etcd/pull/9801) flag.
-  - If empty, Go auto-populates the list.
-- Support [`etcd --cors`](https://github.com/etcd-io/etcd/pull/9490) in v3 HTTP requests (gRPC gateway).
-- Rename [`etcd --log-output` to `etcd --log-outputs`](https://github.com/etcd-io/etcd/pull/9624) to support multiple log outputs.
-  - **`etcd --log-output` will be deprecated in v3.5**.
-- Add [`etcd --logger`](https://github.com/etcd-io/etcd/pull/9572) flag to support [structured logger and multiple log outputs](https://github.com/etcd-io/etcd/issues/9438) in server-side.
-  - **`etcd --logger=capnslog` will be deprecated in v3.5**.
-  - Main motivation is to promote automated etcd monitoring, rather than looking back server logs when it starts breaking. Future development will make etcd log as few as possible, and make etcd easier to monitor with metrics and alerts.
-  - `etcd --logger=capnslog --log-outputs=default` is the default setting and same as previous etcd server logging format.
-  - `etcd --logger=zap --log-outputs=default` is not supported when `etcd --logger=zap`.
-    - Use `etcd --logger=zap --log-outputs=stderr` instead.
-    - Or, use `etcd --logger=zap --log-outputs=systemd/journal` to send logs to the local systemd journal.
-    - Previously, if etcd parent process ID (PPID) is 1 (e.g. run with systemd), `etcd --logger=capnslog --log-outputs=default` redirects server logs to local systemd journal. And if write to journald fails, it writes to `os.Stderr` as a fallback.
-    - However, even with PPID 1, it can fail to dial systemd journal (e.g. run embedded etcd with Docker container). Then, [every single log write will fail](https://github.com/etcd-io/etcd/pull/9729) and fall back to `os.Stderr`, which is inefficient.
-    - To avoid this problem, systemd journal logging must be configured manually.
-  - `etcd --logger=zap --log-outputs=stderr` will log server operations in [JSON-encoded format](https://godoc.org/go.uber.org/zap#NewProductionEncoderConfig) and writes logs to `os.Stderr`. Use this to override journald log redirects.
-  - `etcd --logger=zap --log-outputs=stdout` will log server operations in [JSON-encoded format](https://godoc.org/go.uber.org/zap#NewProductionEncoderConfig) and writes logs to `os.Stdout` Use this to override journald log redirects.
-  - `etcd --logger=zap --log-outputs=a.log` will log server operations in [JSON-encoded format](https://godoc.org/go.uber.org/zap#NewProductionEncoderConfig) and writes logs to the specified file `a.log`.
-  - `etcd --logger=zap --log-outputs=a.log,b.log,c.log,stdout` [writes server logs to multiple files `a.log`, `b.log` and `c.log` at the same time](https://github.com/etcd-io/etcd/pull/9579) and outputs to `os.Stderr`, in [JSON-encoded format](https://godoc.org/go.uber.org/zap#NewProductionEncoderConfig).
-  - `etcd --logger=zap --log-outputs=/dev/null` will discard all server logs.
-- Add [`etcd --log-level`](https://github.com/etcd-io/etcd/pull/10947) flag to support log level.
-  - v3.5 will deprecate `etcd --debug` flag in favor of `etcd --log-level=debug`.
-- Add [`etcd --backend-batch-limit`](https://github.com/etcd-io/etcd/pull/10283) flag.
-- Add [`etcd --backend-batch-interval`](https://github.com/etcd-io/etcd/pull/10283) flag.
-- Fix [`mvcc` "unsynced" watcher restore operation](https://github.com/etcd-io/etcd/pull/9281).
-  - "unsynced" watcher is watcher that needs to be in sync with events that have happened.
-  - That is, "unsynced" watcher is the slow watcher that was requested on old revision.
-  - "unsynced" watcher restore operation was not correctly populating its underlying watcher group.
-  - Which possibly causes [missing events from "unsynced" watchers](https://github.com/etcd-io/etcd/issues/9086).
-  - A node gets network partitioned with a watcher on a future revision, and falls behind receiving a leader snapshot after partition gets removed. When applying this snapshot, etcd watch storage moves current synced watchers to unsynced since sync watchers might have become stale during network partition. And reset synced watcher group to restart watcher routines. Previously, there was a bug when moving from synced watcher group to unsynced, thus client would miss events when the watcher was requested to the network-partitioned node.
-- Fix [`mvcc` server panic from restore operation](https://github.com/etcd-io/etcd/pull/9775).
-  - Let's assume that a watcher had been requested with a future revision X and sent to node A that became network-partitioned thereafter. Meanwhile, cluster makes progress. Then when the partition gets removed, the leader sends a snapshot to node A. Previously if the snapshot's latest revision is still lower than the watch revision X,  **etcd server panicked** during snapshot restore operation.
-  - Now, this server-side panic has been fixed.
-- Fix [server panic on invalid Election Proclaim/Resign HTTP(S) requests](https://github.com/etcd-io/etcd/pull/9379).
-  - Previously, wrong-formatted HTTP requests to Election API could trigger panic in etcd server.
-  - e.g. `curl -L http://localhost:2379/v3/election/proclaim -X POST -d '{"value":""}'`, `curl -L http://localhost:2379/v3/election/resign -X POST -d '{"value":""}'`.
-- Fix [revision-based compaction retention parsing](https://github.com/etcd-io/etcd/pull/9339).
-  - Previously, `etcd --auto-compaction-mode revision --auto-compaction-retention 1` was [translated to revision retention 3600000000000](https://github.com/etcd-io/etcd/issues/9337).
-  - Now, `etcd --auto-compaction-mode revision --auto-compaction-retention 1` is correctly parsed as revision retention 1.
-- Prevent [overflow by large `TTL` values for `Lease` `Grant`](https://github.com/etcd-io/etcd/pull/9399).
-  - `TTL` parameter to `Grant` request is unit of second.
-  - Leases with too large `TTL` values exceeding `math.MaxInt64` [expire in unexpected ways](https://github.com/etcd-io/etcd/issues/9374).
-  - Server now returns `rpctypes.ErrLeaseTTLTooLarge` to client, when the requested `TTL` is larger than *9,000,000,000 seconds* (which is >285 years).
-  - Again, etcd `Lease` is meant for short-periodic keepalives or sessions, in the range of seconds or minutes. Not for hours or days!
-- Fix [expired lease revoke](https://github.com/etcd-io/etcd/pull/10693).
-  - Fix ["the key is not deleted when the bound lease expires"](https://github.com/etcd-io/etcd/issues/10686).
-- Enable etcd server [`raft.Config.CheckQuorum` when starting with `ForceNewCluster`](https://github.com/etcd-io/etcd/pull/9347).
-- Allow [non-WAL files in `etcd --wal-dir` directory](https://github.com/etcd-io/etcd/pull/9743).
-  - Previously, existing files such as [`lost+found`](https://github.com/etcd-io/etcd/issues/7287) in WAL directory prevent etcd server boot.
-  - Now, WAL directory that contains only `lost+found` or a file that's not suffixed with `.wal` is considered non-initialized.
-- Fix [`ETCD_CONFIG_FILE` env variable parsing in `etcd`](https://github.com/etcd-io/etcd/pull/10762).
-- Fix [race condition in `rafthttp` transport pause/resume](https://github.com/etcd-io/etcd/pull/10826).
-- Fix [server crash from creating an empty role](https://github.com/etcd-io/etcd/pull/10907).
-  - Previously, creating a role with an empty name crashed etcd server with an error code `Unavailable`.
-  - Now, creating a role with an empty name is not allowed with an error code `InvalidArgument`.
-
-### API
-
-- Add `isLearner` field to `etcdserverpb.Member`, `etcdserverpb.MemberAddRequest` and `etcdserverpb.StatusResponse` as part of [raft learner implementation](https://github.com/etcd-io/etcd/pull/10725).
-- Add `MemberPromote` rpc to `etcdserverpb.Cluster` interface and the corresponding `MemberPromoteRequest` and `MemberPromoteResponse` as part of [raft learner implementation](https://github.com/etcd-io/etcd/pull/10725).
-- Add [`snapshot`](https://github.com/etcd-io/etcd/pull/9118) package for snapshot restore/save operations (see [`godoc.org/github.com/etcd/clientv3/snapshot`](https://godoc.org/github.com/coreos/etcd/clientv3/snapshot) for more).
-- Add [`watch_id` field to `etcdserverpb.WatchCreateRequest`](https://github.com/etcd-io/etcd/pull/9065) to allow user-provided watch ID to `mvcc`.
-  - Corresponding `watch_id` is returned via `etcdserverpb.WatchResponse`, if any.
-- Add [`fragment` field to `etcdserverpb.WatchCreateRequest`](https://github.com/etcd-io/etcd/pull/9291) to request etcd server to [split watch events](https://github.com/etcd-io/etcd/issues/9294) when the total size of events exceeds `etcd --max-request-bytes` flag value plus gRPC-overhead 512 bytes.
-  - The default server-side request bytes limit is `embed.DefaultMaxRequestBytes` which is 1.5 MiB plus gRPC-overhead 512 bytes.
-  - If watch response events exceed this server-side request limit and watch request is created with `fragment` field `true`, the server will split watch events into a set of chunks, each of which is a subset of watch events below server-side request limit.
-  - Useful when client-side has limited bandwidths.
-  - For example, watch response contains 10 events, where each event is 1 MiB. And server `etcd --max-request-bytes` flag value is 1 MiB. Then, server will send 10 separate fragmented events to the client.
-  - For example, watch response contains 5 events, where each event is 2 MiB. And server `etcd --max-request-bytes` flag value is 1 MiB and `clientv3.Config.MaxCallRecvMsgSize` is 1 MiB. Then, server will try to send 5 separate fragmented events to the client, and the client will error with `"code = ResourceExhausted desc = grpc: received message larger than max (...)"`.
-  - Client must implement fragmented watch event merge (which `clientv3` does in etcd v3.4).
-- Add [`raftAppliedIndex` field to `etcdserverpb.StatusResponse`](https://github.com/etcd-io/etcd/pull/9176) for current Raft applied index.
-- Add [`errors` field to `etcdserverpb.StatusResponse`](https://github.com/etcd-io/etcd/pull/9206) for server-side error.
-  - e.g. `"etcdserver: no leader", "NOSPACE", "CORRUPT"`
-- Add [`dbSizeInUse` field to `etcdserverpb.StatusResponse`](https://github.com/etcd-io/etcd/pull/9256) for actual DB size after compaction.
-- Add [`WatchRequest.WatchProgressRequest`](https://github.com/etcd-io/etcd/pull/9869).
-  - To manually trigger broadcasting watch progress event (empty watch response with latest header) to all associated watch streams.
-  - Think of it as `WithProgressNotify` that can be triggered manually.
-
-Note: **v3.5 will deprecate `etcd --log-package-levels` flag for `capnslog`**; `etcd --logger=zap --log-outputs=stderr` will the default. **v3.5 will deprecate `[CLIENT-URL]/config/local/log` endpoint.**
-
-### Package `embed`
-
-- Add [`embed.Config.CipherSuites`](https://github.com/etcd-io/etcd/pull/9801) to specify a list of supported cipher suites for TLS handshake between client/server  and peers.
-  - If empty, Go auto-populates the list.
-  - Both `embed.Config.ClientTLSInfo.CipherSuites` and `embed.Config.CipherSuites` cannot be non-empty at the same time.
-  - If not empty, specify either `embed.Config.ClientTLSInfo.CipherSuites` or `embed.Config.CipherSuites`.
-- Add [`embed.Config.InitialElectionTickAdvance`](https://github.com/etcd-io/etcd/pull/9591) to enable/disable initial election tick fast-forward.
-  - `embed.NewConfig()` would return `*embed.Config` with `InitialElectionTickAdvance` as true by default.
-- Define [`embed.CompactorModePeriodic`](https://godoc.org/github.com/etcd-io/etcd/embed#pkg-variables) for `compactor.ModePeriodic`.
-- Define [`embed.CompactorModeRevision`](https://godoc.org/github.com/etcd-io/etcd/embed#pkg-variables) for `compactor.ModeRevision`.
-- Change [`embed.Config.CorsInfo` in `*cors.CORSInfo` type to `embed.Config.CORS` in `map[string]struct{}` type](https://github.com/etcd-io/etcd/pull/9490).
-- Remove [`embed.Config.SetupLogging`](https://github.com/etcd-io/etcd/pull/9572).
-  - Now logger is set up automatically based on [`embed.Config.Logger`, `embed.Config.LogOutputs`, `embed.Config.Debug` fields](https://github.com/etcd-io/etcd/pull/9572).
-- Add [`embed.Config.Logger`](https://github.com/etcd-io/etcd/pull/9518) to support [structured logger `zap`](https://github.com/uber-go/zap) in server-side.
-- Add [`embed.Config.LogLevel`](https://github.com/etcd-io/etcd/pull/10947).
-- Rename `embed.Config.SnapCount` field to [`embed.Config.SnapshotCount`](https://github.com/etcd-io/etcd/pull/9745), to be consistent with the flag name `etcd --snapshot-count`.
-- Rename [**`embed.Config.LogOutput`** to **`embed.Config.LogOutputs`**](https://github.com/etcd-io/etcd/pull/9624) to support multiple log outputs.
-- Change [**`embed.Config.LogOutputs`** type from `string` to `[]string`](https://github.com/etcd-io/etcd/pull/9579) to support multiple log outputs.
-- Add [`embed.Config.BackendBatchLimit`](https://github.com/etcd-io/etcd/pull/10283) field.
-- Add [`embed.Config.BackendBatchInterval`](https://github.com/etcd-io/etcd/pull/10283) field.
-- Make [`embed.DefaultEnableV2` `false` default](https://github.com/etcd-io/etcd/pull/10935).
-
-### Package `pkg/adt`
-
-- Change [`pkg/adt.IntervalTree` from `struct` to `interface`](https://github.com/etcd-io/etcd/pull/10959).
-  - See [`pkg/adt` README](https://github.com/etcd-io/etcd/tree/master/pkg/adt) and [`pkg/adt` godoc](https://godoc.org/go.etcd.io/etcd/pkg/adt).
-- Improve [`pkg/adt.IntervalTree` test coverage](https://github.com/etcd-io/etcd/pull/10959).
-  - See [`pkg/adt` README](https://github.com/etcd-io/etcd/tree/master/pkg/adt) and [`pkg/adt` godoc](https://godoc.org/go.etcd.io/etcd/pkg/adt).
-- Fix [Red-Black tree to maintain black-height property](https://github.com/etcd-io/etcd/pull/10978).
-  - Previously, delete operation violates [black-height property](https://github.com/etcd-io/etcd/issues/10965).
-
-### Package `integration`
-
-- Add [`CLUSTER_DEBUG` to enable test cluster logging](https://github.com/etcd-io/etcd/pull/9678).
-  - Deprecated `capnslog` in integration tests.
-
-### client v3
-
-- Add [`MemberAddAsLearner`](https://github.com/etcd-io/etcd/pull/10725) to `Clientv3.Cluster` interface. This API is used to add a learner member to etcd cluster.
-- Add [`MemberPromote`](https://github.com/etcd-io/etcd/pull/10727) to `Clientv3.Cluster` interface. This API is used to promote a learner member in etcd cluster.
-- Client may receive [`rpctypes.ErrLeaderChanged`](https://github.com/etcd-io/etcd/pull/10094) from server.
-  - Now linearizable requests with read index would fail fast when there is a leadership change, instead of waiting until context timeout.
-- Add [`WithFragment` `OpOption`](https://github.com/etcd-io/etcd/pull/9291) to support [watch events fragmentation](https://github.com/etcd-io/etcd/issues/9294) when the total size of events exceeds `etcd --max-request-bytes` flag value plus gRPC-overhead 512 bytes.
-  - Watch fragmentation is disabled by default.
-  - The default server-side request bytes limit is `embed.DefaultMaxRequestBytes` which is 1.5 MiB plus gRPC-overhead 512 bytes.
-  - If watch response events exceed this server-side request limit and watch request is created with `fragment` field `true`, the server will split watch events into a set of chunks, each of which is a subset of watch events below server-side request limit.
-  - Useful when client-side has limited bandwidths.
-  - For example, watch response contains 10 events, where each event is 1 MiB. And server `etcd --max-request-bytes` flag value is 1 MiB. Then, server will send 10 separate fragmented events to the client.
-  - For example, watch response contains 5 events, where each event is 2 MiB. And server `etcd --max-request-bytes` flag value is 1 MiB and `clientv3.Config.MaxCallRecvMsgSize` is 1 MiB. Then, server will try to send 5 separate fragmented events to the client, and the client will error with `"code = ResourceExhausted desc = grpc: received message larger than max (...)"`.
-- Add [`Watcher.RequestProgress` method](https://github.com/etcd-io/etcd/pull/9869).
-  - To manually trigger broadcasting watch progress event (empty watch response with latest header) to all associated watch streams.
-  - Think of it as `WithProgressNotify` that can be triggered manually.
-- Fix [lease keepalive interval updates when response queue is full](https://github.com/etcd-io/etcd/pull/9952).
-  - If `<-chan *clientv3LeaseKeepAliveResponse` from `clientv3.Lease.KeepAlive` was never consumed or channel is full, client was [sending keepalive request every 500ms](https://github.com/etcd-io/etcd/issues/9911) instead of expected rate of every "TTL / 3" duration.
-- Change [snapshot file permissions](https://github.com/etcd-io/etcd/pull/9977): On Linux, the snapshot file changes from readable by all (mode 0644) to readable by the user only (mode 0600).
-- Client may choose to send keepalive pings to server using [`PermitWithoutStream`](https://github.com/etcd-io/etcd/pull/10146).
-  - By setting `PermitWithoutStream` to true, client can send keepalive pings to server without any active streams(RPCs). In other words, it allows sending keepalive pings with unary or simple RPC calls.
-  - `PermitWithoutStream` is set to false by default.
-- Fix logic on [release lock key if cancelled](https://github.com/etcd-io/etcd/pull/10153) in `clientv3/concurrency` package.
-- Fix [`(*Client).Endpoints()` method race condition](https://github.com/etcd-io/etcd/pull/10595).
-- Deprecated [`grpc.ErrClientConnClosing`](https://github.com/etcd-io/etcd/pull/10981).
-  - `clientv3` and `proxy/grpcproxy` now does not return `grpc.ErrClientConnClosing`.
-  - `grpc.ErrClientConnClosing` has been [deprecated in gRPC >= 1.10](https://github.com/grpc/grpc-go/pull/1854).
-  - Use `clientv3.IsConnCanceled(error)` or `google.golang.org/grpc/status.FromError(error)` instead.
-
-### etcdctl v3
-
-- Make [`ETCDCTL_API=3 etcdctl` default](https://github.com/etcd-io/etcd/issues/9600).
-  - Now, `etcdctl set foo bar` must be `ETCDCTL_API=2 etcdctl set foo bar`.
-  - Now, `ETCDCTL_API=3 etcdctl put foo bar` could be just `etcdctl put foo bar`.
-- Add [`etcdctl member add --learner` and `etcdctl member promote`](https://github.com/etcd-io/etcd/pull/10725) to add and promote raft learner member in etcd cluster.
-- Add [`etcdctl --password`](https://github.com/etcd-io/etcd/pull/9730) flag.
-  - To support [`:` character in user name](https://github.com/etcd-io/etcd/issues/9691).
-  - e.g. `etcdctl --user user --password password get foo`
-- Add [`etcdctl user add --new-user-password`](https://github.com/etcd-io/etcd/pull/9730) flag.
-- Add [`etcdctl check datascale`](https://github.com/etcd-io/etcd/pull/9185) command.
-- Add [`etcdctl check datascale --auto-compact, --auto-defrag`](https://github.com/etcd-io/etcd/pull/9351) flags.
-- Add [`etcdctl check perf --auto-compact, --auto-defrag`](https://github.com/etcd-io/etcd/pull/9330) flags.
-- Add [`etcdctl defrag --cluster`](https://github.com/etcd-io/etcd/pull/9390) flag.
-- Add ["raft applied index" field to `endpoint status`](https://github.com/etcd-io/etcd/pull/9176).
-- Add ["errors" field to `endpoint status`](https://github.com/etcd-io/etcd/pull/9206).
-- Add [`etcdctl endpoint health --write-out` support](https://github.com/etcd-io/etcd/pull/9540).
-  - Previously, [`etcdctl endpoint health --write-out json` did not work](https://github.com/etcd-io/etcd/issues/9532).
-- Add [missing newline in `etcdctl endpoint health`](https://github.com/etcd-io/etcd/pull/10793).
-- Fix [`etcdctl watch [key] [range_end] -- [exec-command…]`](https://github.com/etcd-io/etcd/pull/9688) parsing.
-  - Previously,  `ETCDCTL_API=3 etcdctl watch foo -- echo watch event received` panicked.
-- Fix [`etcdctl move-leader` command for TLS-enabled endpoints](https://github.com/etcd-io/etcd/pull/9807).
-- Add [`progress` command to `etcdctl watch --interactive`](https://github.com/etcd-io/etcd/pull/9869).
-  - To manually trigger broadcasting watch progress event (empty watch response with latest header) to all associated watch streams.
-  - Think of it as `WithProgressNotify` that can be triggered manually.
-- Add [timeout](https://github.com/etcd-io/etcd/pull/10301) to `etcdctl snapshot
-  save`.
-  - User can specify timeout of `etcdctl snapshot save` command using flag `--command-timeout`.
-  - Fix etcdctl to [strip out insecure endpoints from DNS SRV records when using discovery](https://github.com/etcd-io/etcd/pull/10443)
-
-### gRPC proxy
-
-- Fix [etcd server panic from restore operation](https://github.com/etcd-io/etcd/pull/9775).
-  - Let's assume that a watcher had been requested with a future revision X and sent to node A that became network-partitioned thereafter. Meanwhile, cluster makes progress. Then when the partition gets removed, the leader sends a snapshot to node A. Previously if the snapshot's latest revision is still lower than the watch revision X,  **etcd server panicked** during snapshot restore operation.
-  - Especially, gRPC proxy was affected, since it detects a leader loss with a key `"proxy-namespace__lostleader"` and a watch revision `"int64(math.MaxInt64 - 2)"`.
-  - Now, this server-side panic has been fixed.
-- Fix [memory leak in cache layer](https://github.com/etcd-io/etcd/pull/10327).
-- Change [gRPC proxy to expose etcd server endpoint /metrics](https://github.com/etcd-io/etcd/pull/10618).
-  - The metrics that were exposed via the proxy were not etcd server members but instead the proxy itself.
-
-### gRPC gateway
-
-- Replace [gRPC gateway](https://github.com/grpc-ecosystem/grpc-gateway) endpoint `/v3beta` with [`/v3`](https://github.com/etcd-io/etcd/pull/9298).
-  - Deprecated [`/v3alpha`](https://github.com/etcd-io/etcd/pull/9298).
-  - To deprecate [`/v3beta`](https://github.com/etcd-io/etcd/issues/9189) in v3.5.
-  - In v3.4, `curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` still works as a fallback to `curl -L http://localhost:2379/v3/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'`, but `curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` won't work in v3.5. Use `curl -L http://localhost:2379/v3/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` instead.
-- Add API endpoints [`/{v3beta,v3}/lease/leases, /{v3beta,v3}/lease/revoke, /{v3beta,v3}/lease/timetolive`](https://github.com/etcd-io/etcd/pull/9450).
-  - To deprecate [`/{v3beta,v3}/kv/lease/leases, /{v3beta,v3}/kv/lease/revoke, /{v3beta,v3}/kv/lease/timetolive`](https://github.com/etcd-io/etcd/issues/9430) in v3.5.
-- Support [`etcd --cors`](https://github.com/etcd-io/etcd/pull/9490) in v3 HTTP requests (gRPC gateway).
-
-### Package `raft`
-
-- Fix [deadlock during PreVote migration process](https://github.com/etcd-io/etcd/pull/8525).
-- Add [`raft.ErrProposalDropped`](https://github.com/etcd-io/etcd/pull/9067).
-  - Now [`(r *raft) Step` returns `raft.ErrProposalDropped`](https://github.com/etcd-io/etcd/pull/9137) if a proposal has been ignored.
-  - e.g. a node is removed from cluster, or [`raftpb.MsgProp` arrives at current leader while there is an ongoing leadership transfer](https://github.com/etcd-io/etcd/issues/8975).
-- Improve [Raft `becomeLeader` and `stepLeader`](https://github.com/etcd-io/etcd/pull/9073) by keeping track of latest `pb.EntryConfChange` index.
-  - Previously record `pendingConf` boolean field scanning the entire tail of the log, which can delay hearbeat send.
-- Fix [missing learner nodes on `(n *node) ApplyConfChange`](https://github.com/etcd-io/etcd/pull/9116).
-- Add [`raft.Config.MaxUncommittedEntriesSize`](https://github.com/etcd-io/etcd/pull/10167) to limit the total size of the uncommitted entries in bytes.
-  - Once exceeded, raft returns `raft.ErrProposalDropped` error.
-  - Prevent [unbounded Raft log growth](https://github.com/cockroachdb/cockroach/issues/27772).
-  - There was a bug in [PR#10167](https://github.com/etcd-io/etcd/pull/10167) but fixed via [PR#10199](https://github.com/etcd-io/etcd/pull/10199).
-- Add [`raft.Ready.CommittedEntries` pagination using `raft.Config.MaxSizePerMsg`](https://github.com/etcd-io/etcd/pull/9982).
-  - This prevents out-of-memory errors if the raft log has become very large and commits all at once.
-  - Fix [correctness bug in CommittedEntries pagination](https://github.com/etcd-io/etcd/pull/10063).
-- Optimize [message send flow control](https://github.com/etcd-io/etcd/pull/9985).
-  - Leader now sends more append entries if it has more non-empty entries to send after updating flow control information.
-  - Now, Raft allows multiple in-flight append messages.
-- Optimize [memory allocation when boxing slice in `maybeCommit`](https://github.com/etcd-io/etcd/pull/10679).
-  - By boxing a heap-allocated slice header instead of the slice header on the stack, we can avoid an allocation when passing through the sort.Interface interface.
-- Avoid [memory allocation in Raft entry `String` method](https://github.com/etcd-io/etcd/pull/10680).
-- Avoid [multiple memory allocations when merging stable and unstable log](https://github.com/etcd-io/etcd/pull/10684).
-- Extract [progress tracking into own component](https://github.com/etcd-io/etcd/pull/10683).
-  - Add [package `raft/tracker`](https://github.com/etcd-io/etcd/pull/10807).
-  - Optimize [string representation of `Progress`](https://github.com/etcd-io/etcd/pull/10882).
-- Make [relationship between `node` and `RawNode` explicit](https://github.com/etcd-io/etcd/pull/10803).
-- Prevent [learners from becoming leader](https://github.com/etcd-io/etcd/pull/10822).
-- Add [package `raft/quorum` to reason about committed indexes as well as vote outcomes for both majority and joint quorums](https://github.com/etcd-io/etcd/pull/10779).
-  - Bundle [Voters and Learner into `raft/tracker.Config` struct](https://github.com/etcd-io/etcd/pull/10865).
-- Use [membership sets in progress tracking](https://github.com/etcd-io/etcd/pull/10779).
-- Implement [joint quorum computation](https://github.com/etcd-io/etcd/pull/10779).
-- Refactor [`raft/node.go` to centralize configuration change application](https://github.com/etcd-io/etcd/pull/10865).
-- Allow [voter to become learner through snapshot](https://github.com/etcd-io/etcd/pull/10864).
-- Add [package `raft/confchange` to internally support joint consensus](https://github.com/etcd-io/etcd/pull/10779).
-- Use [`RawNode` for node's event loop](https://github.com/etcd-io/etcd/pull/10892).
-- Add [`RawNode.Bootstrap` method](https://github.com/etcd-io/etcd/pull/10892).
-- Add [`raftpb.ConfChangeV2` to use joint quorums](https://github.com/etcd-io/etcd/pull/10914).
-  - `raftpb.ConfChange` continues to work as today: it allows carrying out a single configuration change. A `pb.ConfChange` proposal gets added to the Raft log as such and is thus also observed by the app during Ready handling, and fed back to ApplyConfChange.
-  - `raftpb.ConfChangeV2` allows joint configuration changes but will continue to carry out configuration changes in "one phase" (i.e. without ever entering a joint config) when this is possible.
-  - `raftpb.ConfChangeV2` messages initiate configuration changes. They support both the simple "one at a time" membership change protocol and full Joint Consensus allowing for arbitrary changes in membership.
-- Change [`raftpb.ConfState.Nodes` to `raftpb.ConfState.Voters`](https://github.com/etcd-io/etcd/pull/10914).
-- Allow [learners to vote, but still learners do not count in quorum](https://github.com/etcd-io/etcd/pull/10998).
-  - necessary in the situation in which a learner has been promoted (i.e. is now a voter) but has not learned about this yet.
-- Fix [restoring joint consensus](https://github.com/etcd-io/etcd/pull/11003).
-- Visit [`Progress` in stable order](https://github.com/etcd-io/etcd/pull/11004).
-- Proactively [probe newly added followers](https://github.com/etcd-io/etcd/pull/11037).
-  - The general expectation in `tracker.Progress.Next == c.LastIndex` is that the follower has no log at all (and will thus likely need a snapshot), though the app may have applied a snapshot out of band before adding the replica (thus making the first index the better choice).
-  - Previously, when the leader applied a new configuration that added voters, it would not immediately probe these voters, delaying when they would be caught up.
-
-### Package `wal`
-
-- Add [`Verify` function to perform corruption check on WAL contents](https://github.com/etcd-io/etcd/pull/10603).
-- Fix [`wal` directory cleanup on creation failures](https://github.com/etcd-io/etcd/pull/10689).
-
-### Tooling
-
-- Add [`etcd-dump-logs --entry-type`](https://github.com/etcd-io/etcd/pull/9628) flag to support WAL log filtering by entry type.
-- Add [`etcd-dump-logs --stream-decoder`](https://github.com/etcd-io/etcd/pull/9790) flag to support custom decoder.
-- Add [`SHA256SUMS`](https://github.com/etcd-io/etcd/pull/11087) file to release assets.
-  - etcd maintainers are a distributed team, this change allows for releases to be cut and validation provided without requiring a signing key.
-
-### Go
-
-- Require [*Go 1.12+*](https://github.com/etcd-io/etcd/pull/10045).
-- Compile with [*Go 1.12.9*](https://golang.org/doc/devel/release.html#go1.12) including [*Go 1.12.8*](https://groups.google.com/d/msg/golang-announce/65QixT3tcmg/DrFiG6vvCwAJ) security fixes.
-
-### Dockerfile
-
-- [Rebase etcd image from Alpine to Debian](https://github.com/etcd-io/etcd/pull/10805) to improve security and maintenance effort for etcd release.
-
-<hr>
-

CHANGELOG-3.5.md

@@ -1,262 +0,0 @@
-
-
-Previous change logs can be found at [CHANGELOG-3.4](https://github.com/etcd-io/etcd/blob/master/CHANGELOG-3.4.md).
-
-
-The minimum recommended etcd versions to run in **production** are 3.2.28+, 3.3.18+, and 3.4.2+.
-
-
-<hr>
-
-
-## v3.5.0 (2021 TBD)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0...v3.5.0) and [v3.5 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_5.md) for any breaking changes.
-
-- [v3.5.0](https://github.com/etcd-io/etcd/releases/tag/v3.5.0) (2020 TBD), see [code changes](https://github.com/etcd-io/etcd/compare/v3.5.0-rc.1...v3.5.0).
-- [v3.5.0-rc.1](https://github.com/etcd-io/etcd/releases/tag/v3.5.0-rc.1) (2020 TBD), see [code changes](https://github.com/etcd-io/etcd/compare/v3.5.0-rc.0...v3.5.0-rc.1).
-- [v3.5.0-rc.0](https://github.com/etcd-io/etcd/releases/tag/v3.5.0-rc.0) (2020 TBD), see [code changes](https://github.com/etcd-io/etcd/compare/v3.4.0...v3.5.0-rc.0).
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.5 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_3_5.md).**
-
-### Breaking Changes
-
-- `go.etcd.io/etcd` Go packages have moved to `go.etcd.io/etcd/{api,pkg,raft,client,etcdctl,server,raft,tests}/v3` to follow the [Go modules](https://github.com/golang/go/wiki/Modules) conventions
-- `go.etcd.io/clientv3/snapshot` SnapshotManager class have moved to `go.etcd.io/clientv3/etcdctl`. 
-   The method `snapshot.Save` to download a snapshot from the remote server was preserved in 'go.etcd.io/clientv3/snapshot`. 
-- `go.etcd.io/client' package got migrated to 'go.etcd.io/client/v2'.
-- Changed behavior of clienv3 API [MemberList](https://github.com/etcd-io/etcd/pull/11639).
-  - Previously, it is directly served with server's local data, which could be stale.
-  - Now, it is served with linearizable guarantee. If the server is disconnected from quorum, `MemberList` call will fail.
-- [gRPC gateway](https://github.com/grpc-ecosystem/grpc-gateway) only supports [`/v3`](TODO) endpoint.
-  - Deprecated [`/v3beta`](https://github.com/etcd-io/etcd/pull/9298).
-  - `curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` does work in v3.5. Use `curl -L http://localhost:2379/v3/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` instead.
-- **`etcd --experimental-enable-v2v3` flag has been deprecated.** Use **`etcd --enable-v2v3`** instead.
-  - Change [`etcd --experimental-enable-v2v3`](TODO) flag to `etcd --enable-v2v3`; v2 storage emulation is now stable.
-- **`etcd --experimental-backend-bbolt-freelist-type` flag has been deprecated.** Use **`etcd --backend-bbolt-freelist-type`** instead. The default type is hashmap and it is stable now.
-- **`etcd --debug` flag has been deprecated.** Use **`etcd --log-level=debug`** instead.
-- Remove [`embed.Config.Debug`](https://github.com/etcd-io/etcd/pull/10947).
-- **`etcd --log-output` flag has been deprecated.** Use **`etcd --log-outputs`** instead.
-- **`etcd --logger=zap --log-outputs=stderr`** is now the default.
-- **`etcd --logger=capnslog` flag value has been deprecated.**
-- **`etcd --logger=zap --log-outputs=default` flag value is not supported.**.
-  - Use `etcd --logger=zap --log-outputs=stderr`.
-  - Or, use `etcd --logger=zap --log-outputs=systemd/journal` to send logs to the local systemd journal.
-  - Previously, if etcd parent process ID (PPID) is 1 (e.g. run with systemd), `etcd --logger=capnslog --log-outputs=default` redirects server logs to local systemd journal. And if write to journald fails, it writes to `os.Stderr` as a fallback.
-  - However, even with PPID 1, it can fail to dial systemd journal (e.g. run embedded etcd with Docker container). Then, [every single log write will fail](https://github.com/etcd-io/etcd/pull/9729) and fall back to `os.Stderr`, which is inefficient.
-  - To avoid this problem, systemd journal logging must be configured manually.
-- **`etcd --log-outputs=stderr`** is now the default.
-- **`etcd --log-package-levels` flag for `capnslog` has been deprecated.** Now, **`etcd --logger=zap --log-outputs=stderr`** is the default.
-- **`[CLIENT-URL]/config/local/log` endpoint has been deprecated, as is `etcd --log-package-levels` flag.**
-  - `curl http://127.0.0.1:2379/config/local/log -XPUT -d '{"Level":"DEBUG"}'` won't work.
-  - Please use `etcd --logger=zap --log-outputs=stderr` instead.
-- Deprecated `etcd_debugging_mvcc_db_total_size_in_bytes` Prometheus metric. Use `etcd_mvcc_db_total_size_in_bytes` instead.
-- Deprecated `etcd_debugging_mvcc_put_total` Prometheus metric. Use `etcd_mvcc_put_total` instead.
-- Deprecated `etcd_debugging_mvcc_delete_total` Prometheus metric. Use `etcd_mvcc_delete_total` instead.
-- Deprecated `etcd_debugging_mvcc_txn_total` Prometheus metric. Use `etcd_mvcc_txn_total` instead.
-- Deprecated `etcd_debugging_mvcc_range_total` Prometheus metric. Use `etcd_mvcc_range_total` instead.
-- Master branch `/version` outputs `3.5.0-pre`, instead of `3.4.0+git`.
-- Changed `proxy` package function signature to [support structured logger](https://github.com/etcd-io/etcd/pull/11614).
-  - Previously, `NewClusterProxy(c *clientv3.Client, advaddr string, prefix string) (pb.ClusterServer, <-chan struct{})`, now `NewClusterProxy(lg *zap.Logger, c *clientv3.Client, advaddr string, prefix string) (pb.ClusterServer, <-chan struct{})`.
-  - Previously, `Register(c *clientv3.Client, prefix string, addr string, ttl int)`, now `Register(lg *zap.Logger, c *clientv3.Client, prefix string, addr string, ttl int) <-chan struct{}`.
-  - Previously, `NewHandler(t *http.Transport, urlsFunc GetProxyURLs, failureWait time.Duration, refreshInterval time.Duration) http.Handler`, now `NewHandler(lg *zap.Logger, t *http.Transport, urlsFunc GetProxyURLs, failureWait time.Duration, refreshInterval time.Duration) http.Handler`.
-- Changed `pkg/flags` function signature to [support structured logger](https://github.com/etcd-io/etcd/pull/11616).
-  - Previously, `SetFlagsFromEnv(prefix string, fs *flag.FlagSet) error`, now `SetFlagsFromEnv(lg *zap.Logger, prefix string, fs *flag.FlagSet) error`.
-  - Previously, `SetPflagsFromEnv(prefix string, fs *pflag.FlagSet) error`, now `SetPflagsFromEnv(lg *zap.Logger, prefix string, fs *pflag.FlagSet) error`.
-- ClientV3 supports [grpc resolver API](https://github.com/etcd-io/etcd/blob/master/client/v3/naming/resolver/resolver.go).
-  - Endpoints can be managed using [endpoints.Manager](https://github.com/etcd-io/etcd/blob/master/client/v3/naming/endpoints/endpoints.go)
-  - Previously supported [GRPCResolver was decomissioned](https://github.com/etcd-io/etcd/pull/12675). Use [resolver](https://github.com/etcd-io/etcd/blob/master/client/v3/naming/resolver/resolver.go) instead.
-
-
-### `etcdctl`
-
-- Make sure [save snapshot downloads checksum for integrity checks](https://github.com/etcd-io/etcd/pull/11896).
-
-### Security
-
-- Add [`TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256` and `TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256` to `etcd --cipher-suites`](https://github.com/etcd-io/etcd/pull/11864).
-- Changed [the format of WAL entries related to auth for not keeping password as a plain text](https://github.com/etcd-io/etcd/pull/11943).
-- Add third party [Security Audit Report](https://github.com/etcd-io/etcd/pull/12201).
-- A [log warning](https://github.com/etcd-io/etcd/pull/12242) is added when etcd use any existing directory that has a permission different than 700 on Linux and 777 on Windows.
-
-### Metrics, Monitoring
-
-See [List of metrics](https://github.com/etcd-io/etcd/tree/master/Documentation/metrics) for all metrics per release.
-
-Note that any `etcd_debugging_*` metrics are experimental and subject to change.
-
-- Deprecated `etcd_debugging_mvcc_db_total_size_in_bytes` Prometheus metric. Use `etcd_mvcc_db_total_size_in_bytes` instead.
-- Deprecated `etcd_debugging_mvcc_put_total` Prometheus metric. Use `etcd_mvcc_put_total` instead.
-- Deprecated `etcd_debugging_mvcc_delete_total` Prometheus metric. Use `etcd_mvcc_delete_total` instead.
-- Deprecated `etcd_debugging_mvcc_txn_total` Prometheus metric. Use `etcd_mvcc_txn_total` instead.
-- Deprecated `etcd_debugging_mvcc_range_total` Prometheus metric. Use `etcd_mvcc_range_total` instead.
-- Add [`etcd_debugging_mvcc_current_revision`](https://github.com/etcd-io/etcd/pull/11126) Prometheus metric.
-- Add [`etcd_debugging_mvcc_compact_revision`](https://github.com/etcd-io/etcd/pull/11126) Prometheus metric.
-- Change [`etcd_cluster_version`](https://github.com/etcd-io/etcd/pull/11254) Prometheus metrics to include only major and minor version.
-- Add [`etcd_debugging_mvcc_total_put_size_in_bytes`](https://github.com/etcd-io/etcd/pull/11374) Prometheus metric.
-- Add [`etcd_server_client_requests_total` with `"type"` and `"client_api_version"` labels](https://github.com/etcd-io/etcd/pull/11687).
-- Add [`etcd_wal_write_bytes_total`](https://github.com/etcd-io/etcd/pull/11738).
-- Add [`etcd_debugging_auth_revision`](https://github.com/etcd-io/etcd/commit/f14d2a087f7b0fd6f7980b95b5e0b945109c95f3).
-- Add [`os_fd_used` and `os_fd_limit` to monitor current OS file descriptors](https://github.com/etcd-io/etcd/pull/12214).
-
-### etcd server
-
-- [`etcd --enable-v2v3`](TODO) flag is now stable.
-  - `etcd --experimental-enable-v2v3` has been deprecated.
-  - Added [more v2v3 integration tests](https://github.com/etcd-io/etcd/pull/9634).
-  - `etcd --enable-v2=true --enable-v2v3=''` by default, to enable v2 API server that is backed by **v2 store**.
-  - `etcd --enable-v2=true --enable-v2v3=/aaa` to enable v2 API server that is backed by **v3 storage**.
-  - `etcd --enable-v2=false --enable-v2v3=''` to disable v2 API server.
-  - `etcd --enable-v2=false --enable-v2v3=/aaa` to disable v2 API server. TODO: error?
-  - Add [`TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256` and `TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256` to `etcd --cipher-suites`](https://github.com/etcd-io/etcd/pull/11864).
-  - Automatically [create parent directory if it does not exist](https://github.com/etcd-io/etcd/pull/9626) (fix [issue#9609](https://github.com/etcd-io/etcd/issues/9609)).
-  - v4.0 will configure `etcd --enable-v2=true --enable-v2v3=/aaa` to enable v2 API server that is backed by **v3 storage**.
-- [`etcd --backend-bbolt-freelist-type`] flag is now stable.
-  - `etcd --experimental-backend-bbolt-freelist-type` has been deprecated.
-- Support [rollback/downgrade](TODO).
-- Deprecate v2 apply on cluster version. [Use v3 request to set cluster version and recover cluster version from v3 backend](https://github.com/etcd-io/etcd/pull/11427).
-- [Fix corruption bug in defrag](https://github.com/etcd-io/etcd/pull/11613).
-- Fix [quorum protection logic when promoting a learner](https://github.com/etcd-io/etcd/pull/11640).
-- Improve [peer corruption checker](https://github.com/etcd-io/etcd/pull/11621) to work when peer mTLS is enabled.
-- Log [`[CLIENT-PORT]/health` check in server side](https://github.com/etcd-io/etcd/pull/11704).
-- Log [successful etcd server-side health check in debug level](https://github.com/etcd-io/etcd/pull/12677).
-- Improve [compaction performance when latest index is greater than 1-million](https://github.com/etcd-io/etcd/pull/11734).
-- [Refactor consistentindex](https://github.com/etcd-io/etcd/pull/11699).
-- [Add log when etcdserver failed to apply command](https://github.com/etcd-io/etcd/pull/11670).
-- Improve [count-only range performance](https://github.com/etcd-io/etcd/pull/11771).
-- Remove [redundant storage restore operation to shorten the startup time](https://github.com/etcd-io/etcd/pull/11779).
-  - With 40 million key test data,it can shorten the startup time from 5 min to 2.5 min.
-- [Fix deadlock bug in mvcc](https://github.com/etcd-io/etcd/pull/11817).
-- Fix [inconsistency between WAL and server snapshot](https://github.com/etcd-io/etcd/pull/11888).
-  - Previously, server restore fails if it had crashed after persisting raft hard state but before saving snapshot.
-  - See https://github.com/etcd-io/etcd/issues/10219 for more.
-  - Add [missing CRC checksum check in WAL validate method otherwise causes panic](https://github.com/etcd-io/etcd/pull/11924).
-  - See https://github.com/etcd-io/etcd/issues/11918.
-- Improve logging around snapshot send and receive.
-- [Push down RangeOptions.limit argv into index tree to reduce memory overhead](https://github.com/etcd-io/etcd/pull/11990).
-- Add [reason field for /health response](https://github.com/etcd-io/etcd/pull/11983).
-- Add [`--unsafe-no-fsync`](https://github.com/etcd-io/etcd/pull/11946) flag.
-  - Setting the flag disables all uses of fsync, which is unsafe and will cause data loss. This flag makes it possible to run an etcd node for testing and development without placing lots of load on the file system.
-- Add [etcd --auth-token-ttl](https://github.com/etcd-io/etcd/pull/11980) flag to customize `simpleTokenTTL` settings.
-- Improve [`runtime.FDUsage` call pattern to reduce objects malloc of Memory Usage and CPU Usage](https://github.com/etcd-io/etcd/pull/11986).
-- Improve [mvcc.watchResponse channel Memory Usage](https://github.com/etcd-io/etcd/pull/11987).
-- Log [expensive request info in UnaryInterceptor](https://github.com/etcd-io/etcd/pull/12086).
-- [Fix invalid Go type in etcdserverpb](https://github.com/etcd-io/etcd/pull/12000).
-- [Improve healthcheck by using v3 range request and its corresponding timeout](https://github.com/etcd-io/etcd/pull/12195).
-- Add [`etcd --experimental-watch-progress-notify-interval`](https://github.com/etcd-io/etcd/pull/12216) flag to make watch progress notify interval configurable.
-- Fix [server panic in slow writes warnings](https://github.com/etcd-io/etcd/issues/12197).
-  - Fixed via [PR#12238](https://github.com/etcd-io/etcd/pull/12238).
-- [Fix server panic](https://github.com/etcd-io/etcd/pull/12288) when force-new-cluster flag is enabled in a cluster which had learner node.
-- Add [`--self-signed-cert-validity`](https://github.com/etcd-io/etcd/pull/12429) flag to support setting certificate expiration time.
-  - Notice, certificates generated by etcd are valid for 1 year by default when specifying the auto-tls or peer-auto-tls option.
-
-### Package `runtime`
-
-- Optimize [`runtime.FDUsage` by removing unnecessary sorting](https://github.com/etcd-io/etcd/pull/12214).
-
-### Package `embed`
-
-- Remove [`embed.Config.Debug`](https://github.com/etcd-io/etcd/pull/10947).
-  - Use `embed.Config.LogLevel` instead.
-- Add [`embed.Config.ZapLoggerBuilder`](https://github.com/etcd-io/etcd/pull/11147) to allow creating a custom zap logger.
-- Replace [global `*zap.Logger` with etcd server logger object](https://github.com/etcd-io/etcd/pull/12212).
-
-### Package `clientv3`
-
-- Remove [excessive watch cancel logging messages](https://github.com/etcd-io/etcd/pull/12187).
-  - See [kubernetes/kubernetes#93450](https://github.com/kubernetes/kubernetes/issues/93450).
-- Add [`TryLock`](https://github.com/etcd-io/etcd/pull/11104) method to `clientv3/concurrency/Mutex`. A non-blocking method on `Mutex` which does not wait to get lock on the Mutex, returns immediately if Mutex is locked by another session.
-- Fix [client balancer failover against multiple endpoints](https://github.com/etcd-io/etcd/pull/11184).
-  - Fix [`"kube-apiserver: failover on multi-member etcd cluster fails certificate check on DNS mismatch"`](https://github.com/kubernetes/kubernetes/issues/83028).
-- Fix [IPv6 endpoint parsing in client](https://github.com/etcd-io/etcd/pull/11211).
-  - Fix ["1.16: etcd client does not parse IPv6 addresses correctly when members are joining" (kubernetes#83550)](https://github.com/kubernetes/kubernetes/issues/83550).
-- Fix [errors caused by grpc changing balancer/resolver API](https://github.com/etcd-io/etcd/pull/11564). This change is compatible with grpc >= [v1.26.0](https://github.com/grpc/grpc-go/releases/tag/v1.26.0), but is not compatible with < v1.26.0 version.
-- Use [ServerName as the authority](https://github.com/etcd-io/etcd/pull/11574) after bumping to grpc v1.26.0. Remove workaround in [#11184](https://github.com/etcd-io/etcd/pull/11184).
-- Fix [`"hasleader"` metadata embedding](https://github.com/etcd-io/etcd/pull/11687).
-  - Previously, `clientv3.WithRequireLeader(ctx)` was overwriting existing context keys.
-- Fix [watch leak caused by lazy cancellation](https://github.com/etcd-io/etcd/pull/11850). When clients cancel their watches, a cancel request will now be immediately sent to the server instead of waiting for the next watch event.
-- Make sure [save snapshot downloads checksum for integrity checks](https://github.com/etcd-io/etcd/pull/11896).
-- Fix [auth token invalid after watch reconnects](https://github.com/etcd-io/etcd/pull/12264). Get AuthToken automatically when clientConn is ready.
-- Improve [clientv3:get AuthToken gracefully without extra connection](https://github.com/etcd-io/etcd/pull/12165).
-- Changed [clientv3 dialing code](https://github.com/etcd-io/etcd/pull/12671) to use grpc resolver API instead of custom balancer.
-  - Endpoints self identify now as `etcd-endpoints://{id}/#initially={list of endpoints}` e.g. `etcd-endpoints://0xc0009d8540/#initially=[localhost:2079]`
-
-### Package `lease`
-
-- Fix [memory leak in follower nodes](https://github.com/etcd-io/etcd/pull/11731).
-  - https://github.com/etcd-io/etcd/issues/11495
-  - https://github.com/etcd-io/etcd/issues/11730
-- Make sure [grant/revoke won't be applied repeatedly after restarting etcd](https://github.com/etcd-io/etcd/pull/11935).
-
-### Package `wal`
-
-- Add [`etcd_wal_write_bytes_total`](https://github.com/etcd-io/etcd/pull/11738).
-- Handle [out-of-range slice bound in `ReadAll` and entry limit in `decodeRecord`](https://github.com/etcd-io/etcd/pull/11793).
-
-### etcdctl v3
-
-- Fix `etcdctl member add` command to prevent potential timeout. ([PR#11194](https://github.com/etcd-io/etcd/pull/11194) and [PR#11638](https://github.com/etcd-io/etcd/pull/11638))
-- Add [`etcdctl watch --progress-notify`](https://github.com/etcd-io/etcd/pull/11462) flag.
-- Add [`etcdctl auth status`](https://github.com/etcd-io/etcd/pull/11536) command to check if authentication is enabled
-- Add [`etcdctl get --count-only`](https://github.com/etcd-io/etcd/pull/11743) flag for output type `fields`.
-- Add [`etcdctl member list -w=json --hex`](https://github.com/etcd-io/etcd/pull/11812) flag to print memberListResponse in hex format json.
-
-### gRPC gateway
-
-- [gRPC gateway](https://github.com/grpc-ecosystem/grpc-gateway) only supports [`/v3`](TODO) endpoint.
-  - Deprecated [`/v3beta`](https://github.com/etcd-io/etcd/pull/9298).
-  - `curl -L http://localhost:2379/v3beta/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` does work in v3.5. Use `curl -L http://localhost:2379/v3/kv/put -X POST -d '{"key": "Zm9v", "value": "YmFy"}'` instead.
-
-### gRPC Proxy
-
-- Fix [`panic on error`](https://github.com/etcd-io/etcd/pull/11694) for metrics handler.
-- Add [gRPC keepalive related flags](https://github.com/etcd-io/etcd/pull/11711) `grpc-keepalive-min-time`, `grpc-keepalive-interval` and `grpc-keepalive-timeout`.
-- [Fix grpc watch proxy hangs when failed to cancel a watcher](https://github.com/etcd-io/etcd/pull/12030) .
-- Add [metrics handler for grpcproxy self](https://github.com/etcd-io/etcd/pull/12107).
-- Add [health handler for grpcproxy self](https://github.com/etcd-io/etcd/pull/12114).
-
-### Auth
-
-- Fix [NoPassword check when adding user through GRPC gateway](https://github.com/etcd-io/etcd/pull/11418) ([issue#11414](https://github.com/etcd-io/etcd/issues/11414))
-- Fix bug where [some auth related messages are logged at wrong level](https://github.com/etcd-io/etcd/pull/11586)
-- [Fix a data corruption bug by saving consistent index](https://github.com/etcd-io/etcd/pull/11652).
-- [Improve checkPassword performance](https://github.com/etcd-io/etcd/pull/11735).
-- [Add authRevision field in AuthStatus](https://github.com/etcd-io/etcd/pull/11659).
-
-### API
-
-- Add [`/v3/auth/status`](https://github.com/etcd-io/etcd/pull/11536) endpoint to check if authentication is enabled
-- [Add `Linearizable` field to `etcdserverpb.MemberListRequest`](https://github.com/etcd-io/etcd/pull/11639).
-
-### Package `netutil`
-
-- Remove [`netutil.DropPort/RecoverPort/SetLatency/RemoveLatency`](https://github.com/etcd-io/etcd/pull/12491).
-  - These are not used anymore. They were only used for older versions of functional testing.
-  - Removed to adhere to best security practices, minimize arbitrary shell invocation.
-
-### `tools/etcd-dump-metrics`
-
-- Implement [input validation to prevent arbitrary shell invocation](https://github.com/etcd-io/etcd/pull/12491).
-
-### Dependency
-
-- Upgrade [`google.golang.org/grpc`](https://github.com/grpc/grpc-go/releases) from [**`v1.23.0`**](https://github.com/grpc/grpc-go/releases/tag/v1.23.0) to [**`v1.26.0`**](https://github.com/grpc/grpc-go/releases/tag/v1.26.0).
-- Upgrade [`go.uber.org/zap`](https://github.com/uber-go/zap/releases) from [**`v1.14.1`**](https://github.com/uber-go/zap/releases/tag/v1.14.1) to [**`v1.15.0`**](https://github.com/uber-go/zap/releases/tag/v1.15.0).
-
-### Release
-
-- Add s390x build support ([PR#11548](https://github.com/etcd-io/etcd/pull/11548) and [PR#11358](https://github.com/etcd-io/etcd/pull/11358))
-
-### Go
-
-- Require [*Go 1.15+*](https://github.com/etcd-io/etcd/pull/11110).
-- Compile with [*Go 1.15*](https://golang.org/doc/devel/release.html#go1.15)
-- etcd uses go [modules](https://github.com/etcd-io/etcd/pull/12279) (instead of vendor dir) to track dependencies.
-
-### Project Governance
-
-- The etcd team has added, a well defined and openly discussed, project [governance](https://github.com/etcd-io/etcd/pull/11175).
-
-
-<hr>
-

CHANGELOG-4.0.md

@@ -1,53 +0,0 @@
-
-
-Previous change logs can be found at [CHANGELOG-3.x](https://github.com/etcd-io/etcd/blob/master/CHANGELOG-3.x.md).
-
-
-The minimum recommended etcd versions to run in **production** are 3.2.28+, 3.3.18+, and 3.4.2+.
-
-
-<hr>
-
-
-## v4.0.0 (TBD)
-
-See [code changes](https://github.com/etcd-io/etcd/compare/v3.5.0...v4.0.0) and [v4.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_4_0.md) for any breaking changes.
-
-**Again, before running upgrades from any previous release, please make sure to read change logs below and [v4.0 upgrade guide](https://github.com/etcd-io/etcd/blob/master/Documentation/upgrades/upgrade_4_0.md).**
-
-### Breaking Changes
-
-- [Secure etcd by default](https://github.com/etcd-io/etcd/issues/9475)?
-- Change `/health` endpoint output.
-  - Previously, `{"health":"true"}`.
-  - Now, `{"health":true}`.
-  - Breaks [Kubernetes `kubectl get componentstatuses` command](https://github.com/kubernetes/kubernetes/issues/58240).
-- Deprecate [`etcd --proxy*`](TODO) flags; **no more v2 proxy**.
-- Deprecate [v2 storage backend](https://github.com/etcd-io/etcd/issues/9232); **no more v2 store**.
-  - v2 API is still supported via [v2 emulation](TODO).
-- Deprecate [`etcdctl backup`](TODO) command.
-- `clientv3.Client.KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAliveResponse, error)` is now [`clientv4.Client.KeepAlive(ctx context.Context, id LeaseID) <-chan *LeaseKeepAliveResponse`](TODO).
-  - Similar to `Watch`, [`KeepAlive` does not return errors](https://github.com/etcd-io/etcd/issues/7488).
-  - If there's an unknown server error, kill all open channels and create a new stream on the next `KeepAlive` call.
-- Rename `github.com/coreos/client` to `github.com/coreos/clientv2`.
-- [`etcd --experimental-initial-corrupt-check`](TODO) has been  deprecated.
-  - Use [`etcd --initial-corrupt-check`](TODO) instead.
-- [`etcd --experimental-corrupt-check-time`](TODO) has been  deprecated.
-  - Use [`etcd --corrupt-check-time`](TODO) instead.
-- Enable TLS 1.13, deprecate TLS cipher suites.
-
-### etcd server
-
-- [`etcd --initial-corrupt-check`](TODO) flag is now stable (`etcd --experimental-initial-corrupt-check` has been  deprecated).
-  - `etcd --initial-corrupt-check=true` by default, to check cluster database hashes before serving client/peer traffic.
-- [`etcd --corrupt-check-time`](TODO) flag is now stable (`etcd --experimental-corrupt-check-time` has been  deprecated).
-  - `etcd --corrupt-check-time=12h` by default, to check cluster database hashes for every 12-hour.
-- Enable TLS 1.13, deprecate TLS cipher suites.
-
-### Go
-
-- Require [*Go 2*](https://blog.golang.org/go2draft).
-
-
-<hr>
-

CONTRIBUTING.md

@@ -15,13 +15,13 @@ etcd is Apache 2.0 licensed and accepts contributions via GitHub pull requests.
 
 ## 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/etcd-io/etcd/blob/master/Documentation/reporting-bugs.md) before submitting a bug report. This document might contain links to known issues, another good reason to take a look there before reporting a bug.
+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://etcd.io/docs/latest/reporting_bugs) before submitting a bug report. This document might contain links to known issues, another good reason to take a look there before reporting a bug.
 
 ## Contribution flow
 
 This is a rough outline of what a contributor's workflow looks like:
 
-- Create a topic branch from where to base the contribution. This is usually master.
+- Create a topic branch from where to base the contribution. This is usually main.
 - Make commits of logical units.
 - Make sure commit messages are in the proper format (see below).
 - Push changes in a topic branch to a personal fork of the repository.

Dockerfile-release.amd64

@@ -1,7 +1,9 @@
-FROM k8s.gcr.io/build-image/debian-base:buster-v1.4.0
+# TODO: move to k8s.gcr.io/build-image/debian-base:bullseye-v1.y.z when patched
+FROM debian:bullseye-20220328
 
 ADD etcd /usr/local/bin/
 ADD etcdctl /usr/local/bin/
+ADD etcdutl /usr/local/bin/
 RUN mkdir -p /var/etcd/
 RUN mkdir -p /var/lib/etcd/
 

Dockerfile-release.arm64

@@ -1,9 +1,12 @@
-FROM k8s.gcr.io/build-image/debian-base-arm64:buster-v1.4.0
+# TODO: move to k8s.gcr.io/build-image/debian-base-arm64:bullseye-1.y.z when patched
+FROM arm64v8/debian:bullseye-20220328
 
 ADD etcd /usr/local/bin/
 ADD etcdctl /usr/local/bin/
+ADD etcdutl /usr/local/bin/
 ADD var/etcd /var/etcd
 ADD var/lib/etcd /var/lib/etcd
+ENV ETCD_UNSUPPORTED_ARCH=arm64
 
 EXPOSE 2379 2380
 

Dockerfile-release.ppc64le

@@ -1,7 +1,9 @@
-FROM k8s.gcr.io/build-image/debian-base-ppc64le:buster-v1.4.0
+# TODO: move to k8s.gcr.io/build-image/debian-base-ppc64le:bullseye-1.y.z when patched
+FROM ppc64le/debian:bullseye-20220328
 
 ADD etcd /usr/local/bin/
 ADD etcdctl /usr/local/bin/
+ADD etcdutl /usr/local/bin/
 ADD var/etcd /var/etcd
 ADD var/lib/etcd /var/lib/etcd
 

Dockerfile-release.s390x

@@ -1,7 +1,9 @@
-FROM k8s.gcr.io/build-image/debian-base-s390x:buster-v1.4.0
+# TODO: move to k8s.gcr.io/build-image/debian-base-s390x:bullseye-1.y.z when patched
+FROM s390x/debian:bullseye-20220328
 
 ADD etcd /usr/local/bin/
 ADD etcdctl /usr/local/bin/
+ADD etcdutl /usr/local/bin/
 ADD var/etcd /var/etcd
 ADD var/lib/etcd /var/lib/etcd
 

Documentation/README.md

@@ -2,5 +2,5 @@
 
 etcd is a distributed key-value store designed to reliably and quickly preserve and provide access to critical data. It enables reliable distributed coordination through distributed locking, leader elections, and write barriers. An etcd cluster is intended for high availability and permanent data storage and retrieval.
 
-These documents have moved to the [etcd-io/website repo](https://github.com/etcd-io/website/), and can be viewed live at [https://etcd.io/docs/current/](https://etcd.io/docs/current/).
+These documents have moved to the [etcd-io/website repo](https://github.com/etcd-io/website/), and can be viewed live at [https://etcd.io/docs/latest/](https://etcd.io/docs/latest/).
 

Documentation/dev-guide/apispec/swagger/rpc.swagger.json

@@ -1247,7 +1247,7 @@
         "tags": [
           "Maintenance"
         ],
-        "summary": "Downgrade requests downgrade, cancel downgrade on the cluster version.",
+        "summary": "Downgrade requests downgrades, verifies feasibility or cancels downgrade\non the cluster version.\nSupported since etcd 3.5.",
         "operationId": "Maintenance_Downgrade",
         "parameters": [
           {

Makefile

@@ -12,6 +12,7 @@
 
 UNAME := $(shell uname)
 XARGS = xargs
+ARCH ?= $(shell go env GOARCH)
 
 # -r is only necessary on GNU xargs.
 ifeq ($(UNAME), Linux)
@@ -24,11 +25,12 @@ build:
 	GO_BUILD_FLAGS="-v" ./build.sh
 	./bin/etcd --version
 	./bin/etcdctl version
+	./bin/etcdutl version
 
 clean:
 	rm -f ./codecov
 	rm -rf ./covdir
-	rm -f ./bin/Dockerfile-release
+	rm -f ./bin/Dockerfile-release*
 	rm -rf ./bin/etcd*
 	rm -rf ./default.etcd
 	rm -rf ./tests/e2e/default.etcd
@@ -53,7 +55,7 @@ docker-remove:
 
 
 
-GO_VERSION ?= 1.15.7
+GO_VERSION ?= 1.16.15
 ETCD_VERSION ?= $(shell git rev-parse --short HEAD || echo "GitNotFound")
 
 TEST_SUFFIX = $(shell date +%s | base64 | head -c 15)
@@ -71,7 +73,7 @@ TMP_DOCKERFILE:=$(shell mktemp)
 #   GO_VERSION=1.14.3 make build-docker-test
 #   make build-docker-test
 #
-#   gcloud docker -- login -u _json_key -p "$(cat /etc/gcp-key-etcd-development.json)" https://gcr.io
+#   gcloud auth configure-docker
 #   GO_VERSION=1.14.3 make push-docker-test
 #   make push-docker-test
 #
@@ -88,7 +90,7 @@ build-docker-test:
 
 push-docker-test:
 	$(info GO_VERSION: $(GO_VERSION))
-	gcloud docker -- push gcr.io/etcd-development/etcd-test:go$(GO_VERSION)
+	docker push gcr.io/etcd-development/etcd-test:go$(GO_VERSION)
 
 pull-docker-test:
 	$(info GO_VERSION: $(GO_VERSION))
@@ -151,15 +153,18 @@ test:
 	$(TEST_OPTS) ./test.sh 2>&1 | tee test-$(TEST_SUFFIX).log
 	! egrep "(--- FAIL:|DATA RACE|panic: test timed out|appears to have leaked)" -B50 -A10 test-$(TEST_SUFFIX).log
 
-test-small:
+test-smoke:
 	$(info log-file: test-$(TEST_SUFFIX).log)
 	PASSES="fmt build unit" ./test.sh 2<&1 | tee test-$(TEST_SUFFIX).log
 
 test-full:
 	$(info log-file: test-$(TEST_SUFFIX).log)
-	PASSES="fmt build unit integration functional e2e grpcproxy" ./test.sh 2<&1 | tee test-$(TEST_SUFFIX).log
+	PASSES="fmt build release unit integration functional e2e grpcproxy" ./test.sh 2<&1 | tee test-$(TEST_SUFFIX).log
 
-docker-test:
+ensure-docker-test-image-exists:
+	make pull-docker-test || ( echo "WARNING: Container Image not found in registry, building locally"; make build-docker-test )
+
+docker-test: ensure-docker-test-image-exists
 	$(info GO_VERSION: $(GO_VERSION))
 	$(info ETCD_VERSION: $(ETCD_VERSION))
 	$(info TEST_OPTS: $(TEST_OPTS))
@@ -192,28 +197,28 @@ docker-test-coverage:
 
 # Example:
 #   make compile-with-docker-test
-#   ETCD_VERSION=v3-test make build-docker-release-master
-#   ETCD_VERSION=v3-test make push-docker-release-master
+#   ETCD_VERSION=v3-test make build-docker-release-main
+#   ETCD_VERSION=v3-test make push-docker-release-main
 #   gsutil -m acl ch -u allUsers:R -r gs://artifacts.etcd-development.appspot.com
 
-build-docker-release-master:
+build-docker-release-main:
 	$(info ETCD_VERSION: $(ETCD_VERSION))
-	cp ./Dockerfile-release ./bin/Dockerfile-release
+	cp ./Dockerfile-release.$(ARCH) ./bin/Dockerfile-release.$(ARCH)
 	docker build \
 	  --network=host \
 	  --tag gcr.io/etcd-development/etcd:$(ETCD_VERSION) \
-	  --file ./bin/Dockerfile-release \
+	  --file ./bin/Dockerfile-release.$(ARCH) \
 	  ./bin
-	rm -f ./bin/Dockerfile-release
+	rm -f ./bin/Dockerfile-release.$(ARCH)
 
 	docker run \
 	  --rm \
 	  gcr.io/etcd-development/etcd:$(ETCD_VERSION) \
-	  /bin/sh -c "/usr/local/bin/etcd --version && /usr/local/bin/etcdctl version"
+	  /bin/sh -c "/usr/local/bin/etcd --version && /usr/local/bin/etcdctl version && /usr/local/bin/etcdutl version"
 
-push-docker-release-master:
+push-docker-release-main:
 	$(info ETCD_VERSION: $(ETCD_VERSION))
-	gcloud docker -- push gcr.io/etcd-development/etcd:$(ETCD_VERSION)
+	docker push gcr.io/etcd-development/etcd:$(ETCD_VERSION)
 
 
 
@@ -222,7 +227,7 @@ push-docker-release-master:
 #   make compile-with-docker-test
 #   make build-docker-static-ip-test
 #
-#   gcloud docker -- login -u _json_key -p "$(cat /etc/gcp-key-etcd-development.json)" https://gcr.io
+#   gcloud auth configure-docker
 #   make push-docker-static-ip-test
 #
 #   gsutil -m acl ch -u allUsers:R -r gs://artifacts.etcd-development.appspot.com
@@ -242,7 +247,7 @@ build-docker-static-ip-test:
 
 push-docker-static-ip-test:
 	$(info GO_VERSION: $(GO_VERSION))
-	gcloud docker -- push gcr.io/etcd-development/etcd-static-ip-test:go$(GO_VERSION)
+	docker push gcr.io/etcd-development/etcd-static-ip-test:go$(GO_VERSION)
 
 pull-docker-static-ip-test:
 	$(info GO_VERSION: $(GO_VERSION))
@@ -281,7 +286,7 @@ docker-static-ip-test-certs-metrics-proxy-run:
 #   make compile-with-docker-test
 #   make build-docker-dns-test
 #
-#   gcloud docker -- login -u _json_key -p "$(cat /etc/gcp-key-etcd-development.json)" https://gcr.io
+#   gcloud auth configure-docker
 #   make push-docker-dns-test
 #
 #   gsutil -m acl ch -u allUsers:R -r gs://artifacts.etcd-development.appspot.com
@@ -312,7 +317,7 @@ build-docker-dns-test:
 
 push-docker-dns-test:
 	$(info GO_VERSION: $(GO_VERSION))
-	gcloud docker -- push gcr.io/etcd-development/etcd-dns-test:go$(GO_VERSION)
+	docker push gcr.io/etcd-development/etcd-dns-test:go$(GO_VERSION)
 
 pull-docker-dns-test:
 	$(info GO_VERSION: $(GO_VERSION))
@@ -421,7 +426,7 @@ docker-dns-test-certs-san-dns-run:
 #   make build-docker-test
 #   make compile-with-docker-test
 #   make build-docker-dns-srv-test
-#   gcloud docker -- login -u _json_key -p "$(cat /etc/gcp-key-etcd-development.json)" https://gcr.io
+#   gcloud auth configure-docker
 #   make push-docker-dns-srv-test
 #   gsutil -m acl ch -u allUsers:R -r gs://artifacts.etcd-development.appspot.com
 #   make pull-docker-dns-srv-test
@@ -446,7 +451,7 @@ build-docker-dns-srv-test:
 
 push-docker-dns-srv-test:
 	$(info GO_VERSION: $(GO_VERSION))
-	gcloud docker -- push gcr.io/etcd-development/etcd-dns-srv-test:go$(GO_VERSION)
+	docker push gcr.io/etcd-development/etcd-dns-srv-test:go$(GO_VERSION)
 
 pull-docker-dns-srv-test:
 	$(info GO_VERSION: $(GO_VERSION))
@@ -528,6 +533,7 @@ build-docker-functional:
 	  /bin/bash -c "./bin/etcd --version && \
 	   ./bin/etcd-failpoints --version && \
 	   ./bin/etcdctl version && \
+	   ./bin/etcdutl version && \
 	   ./bin/etcd-agent -help || true && \
 	   ./bin/etcd-proxy -help || true && \
 	   ./bin/etcd-runner --help || true && \
@@ -537,7 +543,7 @@ build-docker-functional:
 push-docker-functional:
 	$(info GO_VERSION: $(GO_VERSION))
 	$(info ETCD_VERSION: $(ETCD_VERSION))
-	gcloud docker -- push gcr.io/etcd-development/etcd-functional:go$(GO_VERSION)
+	docker push gcr.io/etcd-development/etcd-functional:go$(GO_VERSION)
 
 pull-docker-functional:
 	$(info GO_VERSION: $(GO_VERSION))

README.md

@@ -2,14 +2,16 @@
 
 [![Go Report Card](https://goreportcard.com/badge/github.com/etcd-io/etcd?style=flat-square)](https://goreportcard.com/report/github.com/etcd-io/etcd)
 [![Coverage](https://codecov.io/gh/etcd-io/etcd/branch/master/graph/badge.svg)](https://codecov.io/gh/etcd-io/etcd)
-[![Build Status Travis](https://img.shields.io/travis/etcd-io/etcdlabs.svg?style=flat-square&&branch=master)](https://travis-ci.com/etcd-io/etcd)
-[![Build Status Semaphore](https://semaphoreci.com/api/v1/etcd-io/etcd/branches/master/shields_badge.svg)](https://semaphoreci.com/etcd-io/etcd)
+[![Tests](https://github.com/etcd-io/etcd/actions/workflows/tests.yaml/badge.svg)](https://github.com/etcd-io/etcd/actions/workflows/tests.yaml)
+[![asset-transparency](https://github.com/etcd-io/etcd/actions/workflows/asset-transparency.yaml/badge.svg)](https://github.com/etcd-io/etcd/actions/workflows/asset-transparency.yaml)
+[![codeql-analysis](https://github.com/etcd-io/etcd/actions/workflows/codeql-analysis.yml/badge.svg)](https://github.com/etcd-io/etcd/actions/workflows/codeql-analysis.yml)
+[![self-hosted-linux-arm64-graviton2-tests](https://github.com/etcd-io/etcd/actions/workflows/self-hosted-linux-arm64-graviton2-tests.yml/badge.svg)](https://github.com/etcd-io/etcd/actions/workflows/self-hosted-linux-arm64-graviton2-tests.yml)
 [![Docs](https://img.shields.io/badge/docs-latest-green.svg)](https://etcd.io/docs)
 [![Godoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](https://godoc.org/github.com/etcd-io/etcd)
 [![Releases](https://img.shields.io/github/release/etcd-io/etcd/all.svg?style=flat-square)](https://github.com/etcd-io/etcd/releases)
-[![LICENSE](https://img.shields.io/github/license/etcd-io/etcd.svg?style=flat-square)](https://github.com/etcd-io/etcd/blob/master/LICENSE)
+[![LICENSE](https://img.shields.io/github/license/etcd-io/etcd.svg?style=flat-square)](https://github.com/etcd-io/etcd/blob/main/LICENSE)
 
-**Note**: The `master` branch may be in an *unstable or even broken state* during development. Please use [releases][github-release] instead of the `master` branch in order to get stable binaries.
+**Note**: The `main` branch may be in an *unstable or even broken state* during development. For stable versions, see [releases][github-release].
 
 ![etcd Logo](logos/etcd-horizontal-color.svg)
 
@@ -20,9 +22,9 @@ etcd is a distributed reliable key-value store for the most critical data of a d
 * *Fast*: benchmarked 10,000 writes/sec
 * *Reliable*: properly distributed using Raft
 
-etcd is written in Go and uses the [Raft][raft] consensus algorithm to manage a highly-available replicated log.
+etcd is written in Go and uses the [Raft][] consensus algorithm to manage a highly-available replicated log.
 
-etcd is used [in production by many companies](./ADOPTERS.md), and the development team stands behind it in critical deployment scenarios, where etcd is frequently teamed with applications such as [Kubernetes][k8s], [locksmith][locksmith], [vulcand][vulcand], [Doorman][doorman], and many others. Reliability is further ensured by [**rigorous testing**](https://github.com/etcd-io/etcd/tree/master/tests/functional).
+etcd is used [in production by many companies](./ADOPTERS.md), and the development team stands behind it in critical deployment scenarios, where etcd is frequently teamed with applications such as [Kubernetes][k8s], [locksmith][], [vulcand][], [Doorman][], and many others. Reliability is further ensured by [**rigorous testing**](https://github.com/etcd-io/etcd/tree/main/tests/functional).
 
 See [etcdctl][etcdctl] for a simple command line client.
 
@@ -31,7 +33,7 @@ See [etcdctl][etcdctl] for a simple command line client.
 [doorman]: https://github.com/youtube/doorman
 [locksmith]: https://github.com/coreos/locksmith
 [vulcand]: https://github.com/vulcand/vulcand
-[etcdctl]: https://github.com/etcd-io/etcd/tree/master/etcdctl
+[etcdctl]: https://github.com/etcd-io/etcd/tree/main/etcdctl
 
 ## Community meetings
 
@@ -51,7 +53,7 @@ Time:
 - [May 30th, 2019 11:00 AM video](https://youtu.be/2t1R5NATYG4)
 - [Jul 11th, 2019 11:00 AM video](https://youtu.be/k_FZEipWD6Y)
 - [Jul 25, 2019 11:00 AM video](https://youtu.be/VSUJTACO93I)
-- [Aug 22, 2019 11:00 AM video](https://youtu.be/6IBQ-VxQmuM) 
+- [Aug 22, 2019 11:00 AM video](https://youtu.be/6IBQ-VxQmuM)
 - [Sep 19, 2019 11:00 AM video](https://youtu.be/SqfxU9DhBOc)
 - Nov 14, 2019 11:00 AM
 - Dec 12, 2019 11:00 AM
@@ -82,10 +84,10 @@ The easiest way to get etcd is to use one of the pre-built release binaries whic
 
 For more installation guides, please check out [play.etcd.io](http://play.etcd.io) and [operating etcd](https://etcd.io/docs/latest/op-guide).
 
-For those wanting to try the very latest version, [build the latest version of etcd][dl-build] from the `master` branch. This first needs [*Go*](https://golang.org/) installed (version 1.13+ is required). All development occurs on `master`, including new features and bug fixes. Bug fixes are first targeted at `master` and subsequently ported to release branches, as described in the [branch management][branch-management] guide.
+For those wanting to try the very latest version, [build the latest version of etcd][dl-build] from the `main` branch. This first needs [*Go*](https://golang.org/) installed ([version 1.16+](/go.mod#L3) is required). All development occurs on `main`, including new features and bug fixes. Bug fixes are first targeted at `main` and subsequently ported to release branches, as described in the [branch management][branch-management] guide.
 
 [github-release]: https://github.com/etcd-io/etcd/releases
-[branch-management]: https://etcd.io/docs/latest/branch-management
+[branch-management]: https://etcd.io/docs/latest/branch_management
 [dl-build]: https://etcd.io/docs/latest/dl-build#build-the-latest-version
 
 ### Running etcd
@@ -105,7 +107,7 @@ mv /tmp/etcd-download-test/etcd /usr/local/bin/
 etcd
 ```
 
-If etcd is [built from the master branch][dl-build], run it as below:
+If etcd is [built from the main branch][dl-build], run it as below:
 
 ```bash
 ./bin/etcd
@@ -155,15 +157,15 @@ goreman -f ./Procfile.learner start
 
 Now it's time to dig into the full etcd API and other guides.
 
-- Read the full [documentation][fulldoc].
-- Explore the full gRPC [API][api].
+- Read the full [documentation][].
+- Explore the full gRPC [API][].
 - Set up a [multi-machine cluster][clustering].
 - Learn the [config format, env variables and flags][configuration].
 - Find [language bindings and tools][integrations].
 - Use TLS to [secure an etcd cluster][security].
 - [Tune etcd][tuning].
 
-[fulldoc]: https://etcd.io/docs/latest
+[documentation]: https://etcd.io/docs/latest
 [api]: https://etcd.io/docs/latest/learning/api
 [clustering]: https://etcd.io/docs/latest/op-guide/clustering
 [configuration]: https://etcd.io/docs/latest/op-guide/configuration
@@ -192,16 +194,16 @@ See [security disclosure and release process](security/README.md) for details on
 
 ## Issue and PR management
 
-See [issue triage guidelines](Documentation/triage/issues.md) for details on how issues are managed.
+See [issue triage guidelines](https://etcd.io/docs/current/triage/issues/) for details on how issues are managed.
 
-See [PR management](Documentation/triage/PRs.md) for guidelines on how pull requests are managed.
+See [PR management](https://etcd.io/docs/current/triage/prs/) for guidelines on how pull requests are managed.
 
 ## etcd Emeritus Maintainers
 
 These emeritus maintainers dedicated a part of their career to etcd and reviewed code, triaged bugs, and pushed the project forward over a substantial period of time. Their contribution is greatly appreciated.
 
-* Fanmin Shi 
-* Anthony Romano 
+* Fanmin Shi
+* Anthony Romano
 
 ### License
 

api/authpb/auth.pb.go

@@ -612,10 +612,7 @@ func (m *UserAddOptions) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthAuth
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthAuth
 			}
 			if (iNdEx + skippy) > l {
@@ -802,10 +799,7 @@ func (m *User) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthAuth
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthAuth
 			}
 			if (iNdEx + skippy) > l {
@@ -943,10 +937,7 @@ func (m *Permission) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthAuth
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthAuth
 			}
 			if (iNdEx + skippy) > l {
@@ -1065,10 +1056,7 @@ func (m *Role) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthAuth
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthAuth
 			}
 			if (iNdEx + skippy) > l {

api/etcdserverpb/etcdserver.pb.go

@@ -811,10 +811,7 @@ func (m *Request) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthEtcdserver
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthEtcdserver
 			}
 			if (iNdEx + skippy) > l {
@@ -903,10 +900,7 @@ func (m *Metadata) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthEtcdserver
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthEtcdserver
 			}
 			if (iNdEx + skippy) > l {

api/etcdserverpb/raft_internal.pb.go

@@ -1187,10 +1187,7 @@ func (m *RequestHeader) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthRaftInternal
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthRaftInternal
 			}
 			if (iNdEx + skippy) > l {
@@ -2376,10 +2373,7 @@ func (m *InternalRaftRequest) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthRaftInternal
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthRaftInternal
 			}
 			if (iNdEx + skippy) > l {
@@ -2430,10 +2424,7 @@ func (m *EmptyResponse) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthRaftInternal
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthRaftInternal
 			}
 			if (iNdEx + skippy) > l {
@@ -2580,10 +2571,7 @@ func (m *InternalAuthenticateRequest) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthRaftInternal
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthRaftInternal
 			}
 			if (iNdEx + skippy) > l {

api/go.mod

@@ -1,14 +1,15 @@
 module go.etcd.io/etcd/api/v3
 
-go 1.15
+go 1.16
 
 require (
 	github.com/coreos/go-semver v0.3.0
-	github.com/gogo/protobuf v1.3.1
-	github.com/golang/protobuf v1.3.5
-	github.com/grpc-ecosystem/grpc-gateway v1.14.6
-	google.golang.org/genproto v0.0.0-20200513103714-09dca8ec2884
-	google.golang.org/grpc v1.32.0
+	github.com/gogo/protobuf v1.3.2
+	github.com/golang/protobuf v1.5.2
+	github.com/grpc-ecosystem/grpc-gateway v1.16.0
+	google.golang.org/genproto v0.0.0-20210602131652-f16073e35f0c
+	google.golang.org/grpc v1.41.0
+	gopkg.in/yaml.v2 v2.4.0 // indirect
 )
 
 // Bad imports are sometimes causing attempts to pull that code.

api/go.sum

@@ -3,79 +3,158 @@ cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMT
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
+github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
+github.com/cncf/xds/go v0.0.0-20210805033703-aa0b78936158/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/coreos/go-semver v0.3.0 h1:wkHLiw0WNATZnSG7epLsujiMCgPAc9xhjJ4tgnAxmfM=
 github.com/coreos/go-semver v0.3.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
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 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
-github.com/gogo/protobuf v1.3.1 h1:DqDEcV5aeaTmdFBePNpYsp3FlcVH/2ISVVM9Qf8PSls=
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api/membershippb/membership.pb.go

@@ -803,10 +803,7 @@ func (m *RaftAttributes) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthMembership
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthMembership
 			}
 			if (iNdEx + skippy) > l {
@@ -921,10 +918,7 @@ func (m *Attributes) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthMembership
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthMembership
 			}
 			if (iNdEx + skippy) > l {
@@ -1066,10 +1060,7 @@ func (m *Member) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthMembership
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthMembership
 			}
 			if (iNdEx + skippy) > l {
@@ -1152,10 +1143,7 @@ func (m *ClusterVersionSetRequest) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthMembership
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthMembership
 			}
 			if (iNdEx + skippy) > l {
@@ -1261,10 +1249,7 @@ func (m *ClusterMemberAttrSetRequest) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthMembership
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthMembership
 			}
 			if (iNdEx + skippy) > l {
@@ -1367,10 +1352,7 @@ func (m *DowngradeInfoSetRequest) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthMembership
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthMembership
 			}
 			if (iNdEx + skippy) > l {

api/mvccpb/kv.pb.go

@@ -554,10 +554,7 @@ func (m *KeyValue) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthKv
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthKv
 			}
 			if (iNdEx + skippy) > l {
@@ -699,10 +696,7 @@ func (m *Event) Unmarshal(dAtA []byte) error {
 			if err != nil {
 				return err
 			}
-			if skippy < 0 {
-				return ErrInvalidLengthKv
-			}
-			if (iNdEx + skippy) < 0 {
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
 				return ErrInvalidLengthKv
 			}
 			if (iNdEx + skippy) > l {

api/v3rpc/rpctypes/error.go

@@ -58,12 +58,14 @@ var (
 	ErrGRPCRoleNotFound         = status.New(codes.FailedPrecondition, "etcdserver: role name not found").Err()
 	ErrGRPCRoleEmpty            = status.New(codes.InvalidArgument, "etcdserver: role name is empty").Err()
 	ErrGRPCAuthFailed           = status.New(codes.InvalidArgument, "etcdserver: authentication failed, invalid user ID or password").Err()
+	ErrGRPCPermissionNotGiven   = status.New(codes.InvalidArgument, "etcdserver: permission not given").Err()
 	ErrGRPCPermissionDenied     = status.New(codes.PermissionDenied, "etcdserver: permission denied").Err()
 	ErrGRPCRoleNotGranted       = status.New(codes.FailedPrecondition, "etcdserver: role is not granted to the user").Err()
 	ErrGRPCPermissionNotGranted = status.New(codes.FailedPrecondition, "etcdserver: permission is not granted to the role").Err()
 	ErrGRPCAuthNotEnabled       = status.New(codes.FailedPrecondition, "etcdserver: authentication is not enabled").Err()
 	ErrGRPCInvalidAuthToken     = status.New(codes.Unauthenticated, "etcdserver: invalid auth token").Err()
 	ErrGRPCInvalidAuthMgmt      = status.New(codes.InvalidArgument, "etcdserver: invalid auth management").Err()
+	ErrGRPCAuthOldRevision      = status.New(codes.InvalidArgument, "etcdserver: revision of auth store is old").Err()
 
 	ErrGRPCNoLeader                   = status.New(codes.Unavailable, "etcdserver: no leader").Err()
 	ErrGRPCNotLeader                  = status.New(codes.FailedPrecondition, "etcdserver: not leader").Err()
@@ -73,6 +75,7 @@ var (
 	ErrGRPCTimeout                    = status.New(codes.Unavailable, "etcdserver: request timed out").Err()
 	ErrGRPCTimeoutDueToLeaderFail     = status.New(codes.Unavailable, "etcdserver: request timed out, possibly due to previous leader failure").Err()
 	ErrGRPCTimeoutDueToConnectionLost = status.New(codes.Unavailable, "etcdserver: request timed out, possibly due to connection lost").Err()
+	ErrGRPCTimeoutWaitAppliedIndex    = status.New(codes.Unavailable, "etcdserver: request timed out, waiting for the applied index took too long").Err()
 	ErrGRPCUnhealthy                  = status.New(codes.Unavailable, "etcdserver: unhealthy cluster").Err()
 	ErrGRPCCorrupt                    = status.New(codes.DataLoss, "etcdserver: corrupt cluster").Err()
 	ErrGPRCNotSupportedForLearner     = status.New(codes.Unavailable, "etcdserver: rpc not supported for learner").Err()
@@ -84,6 +87,9 @@ var (
 	ErrGRPCDowngradeInProcess            = status.New(codes.FailedPrecondition, "etcdserver: cluster has a downgrade job in progress").Err()
 	ErrGRPCNoInflightDowngrade           = status.New(codes.FailedPrecondition, "etcdserver: no inflight downgrade job").Err()
 
+	ErrGRPCCanceled         = status.New(codes.Canceled, "etcdserver: request canceled").Err()
+	ErrGRPCDeadlineExceeded = status.New(codes.DeadlineExceeded, "etcdserver: context deadline exceeded").Err()
+
 	errStringToError = map[string]error{
 		ErrorDesc(ErrGRPCEmptyKey):      ErrGRPCEmptyKey,
 		ErrorDesc(ErrGRPCKeyNotFound):   ErrGRPCKeyNotFound,
@@ -127,6 +133,7 @@ var (
 		ErrorDesc(ErrGRPCAuthNotEnabled):       ErrGRPCAuthNotEnabled,
 		ErrorDesc(ErrGRPCInvalidAuthToken):     ErrGRPCInvalidAuthToken,
 		ErrorDesc(ErrGRPCInvalidAuthMgmt):      ErrGRPCInvalidAuthMgmt,
+		ErrorDesc(ErrGRPCAuthOldRevision):      ErrGRPCAuthOldRevision,
 
 		ErrorDesc(ErrGRPCNoLeader):                   ErrGRPCNoLeader,
 		ErrorDesc(ErrGRPCNotLeader):                  ErrGRPCNotLeader,
@@ -191,6 +198,7 @@ var (
 	ErrPermissionNotGranted = Error(ErrGRPCPermissionNotGranted)
 	ErrAuthNotEnabled       = Error(ErrGRPCAuthNotEnabled)
 	ErrInvalidAuthToken     = Error(ErrGRPCInvalidAuthToken)
+	ErrAuthOldRevision      = Error(ErrGRPCAuthOldRevision)
 	ErrInvalidAuthMgmt      = Error(ErrGRPCInvalidAuthMgmt)
 
 	ErrNoLeader                   = Error(ErrGRPCNoLeader)
@@ -201,6 +209,7 @@ var (
 	ErrTimeout                    = Error(ErrGRPCTimeout)
 	ErrTimeoutDueToLeaderFail     = Error(ErrGRPCTimeoutDueToLeaderFail)
 	ErrTimeoutDueToConnectionLost = Error(ErrGRPCTimeoutDueToConnectionLost)
+	ErrTimeoutWaitAppliedIndex    = Error(ErrGRPCTimeoutWaitAppliedIndex)
 	ErrUnhealthy                  = Error(ErrGRPCUnhealthy)
 	ErrCorrupt                    = Error(ErrGRPCCorrupt)
 	ErrBadLeaderTransferee        = Error(ErrGRPCBadLeaderTransferee)

api/version/version.go

@@ -26,7 +26,7 @@ import (
 var (
 	// MinClusterVersion is the min cluster version this etcd binary is compatible with.
 	MinClusterVersion = "3.0.0"
-	Version           = "3.5.0-alpha.0"
+	Version           = "3.5.6"
 	APIVersion        = "unknown"
 
 	// Git SHA Value will be set during build

bill-of-materials.json

@@ -17,12 +17,21 @@
 			}
 		]
 	},
+	{
+		"project": "github.com/cenkalti/backoff/v4",
+		"licenses": [
+			{
+				"type": "MIT License",
+				"confidence": 1
+			}
+		]
+	},
 	{
 		"project": "github.com/certifi/gocertifi",
 		"licenses": [
 			{
-				"type": "\"Do What The F*ck You Want To Public License\"",
-				"confidence": 0.3287671232876712
+				"type": "Mozilla Public License 2.0",
+				"confidence": 1
 			}
 		]
 	},
@@ -98,6 +107,15 @@
 			}
 		]
 	},
+	{
+		"project": "github.com/davecgh/go-spew/spew",
+		"licenses": [
+			{
+				"type": "ISC License",
+				"confidence": 0.9850746268656716
+			}
+		]
+	},
 	{
 		"project": "github.com/dustin/go-humanize",
 		"licenses": [
@@ -116,15 +134,6 @@
 			}
 		]
 	},
-	{
-		"project": "github.com/form3tech-oss/jwt-go",
-		"licenses": [
-			{
-				"type": "MIT License",
-				"confidence": 0.9891304347826086
-			}
-		]
-	},
 	{
 		"project": "github.com/getsentry/raven-go",
 		"licenses": [
@@ -143,6 +152,15 @@
 			}
 		]
 	},
+	{
+		"project": "github.com/golang-jwt/jwt/v4",
+		"licenses": [
+			{
+				"type": "MIT License",
+				"confidence": 0.9891304347826086
+			}
+		]
+	},
 	{
 		"project": "github.com/golang/groupcache/lru",
 		"licenses": [
@@ -386,6 +404,15 @@
 			}
 		]
 	},
+	{
+		"project": "github.com/stretchr/testify/assert",
+		"licenses": [
+			{
+				"type": "MIT License",
+				"confidence": 1
+			}
+		]
+	},
 	{
 		"project": "github.com/tmc/grpc-websocket-proxy/wsproxy",
 		"licenses": [
@@ -431,6 +458,15 @@
 			}
 		]
 	},
+	{
+		"project": "go.etcd.io/etcd/client/pkg/v3",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
 	{
 		"project": "go.etcd.io/etcd/client/v2",
 		"licenses": [
@@ -458,6 +494,15 @@
 			}
 		]
 	},
+	{
+		"project": "go.etcd.io/etcd/etcdutl/v3",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
 	{
 		"project": "go.etcd.io/etcd/pkg/v3",
 		"licenses": [
@@ -503,6 +548,69 @@
 			}
 		]
 	},
+	{
+		"project": "go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
+	{
+		"project": "go.opentelemetry.io/otel",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
+	{
+		"project": "go.opentelemetry.io/otel/exporters/otlp/otlptrace",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
+	{
+		"project": "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
+	{
+		"project": "go.opentelemetry.io/otel/sdk",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
+	{
+		"project": "go.opentelemetry.io/otel/trace",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
+	{
+		"project": "go.opentelemetry.io/proto/otlp",
+		"licenses": [
+			{
+				"type": "Apache License 2.0",
+				"confidence": 1
+			}
+		]
+	},
 	{
 		"project": "go.uber.org/atomic",
 		"licenses": [
@@ -593,6 +701,15 @@
 			}
 		]
 	},
+	{
+		"project": "google.golang.org/protobuf",
+		"licenses": [
+			{
+				"type": "BSD 3-clause \"New\" or \"Revised\" License",
+				"confidence": 0.9663865546218487
+			}
+		]
+	},
 	{
 		"project": "gopkg.in/cheggaaa/pb.v1",
 		"licenses": [
@@ -602,6 +719,15 @@
 			}
 		]
 	},
+	{
+		"project": "gopkg.in/natefinch/lumberjack.v2",
+		"licenses": [
+			{
+				"type": "MIT License",
+				"confidence": 1
+			}
+		]
+	},
 	{
 		"project": "gopkg.in/yaml.v2",
 		"licenses": [
@@ -615,6 +741,15 @@
 			}
 		]
 	},
+	{
+		"project": "gopkg.in/yaml.v3",
+		"licenses": [
+			{
+				"type": "MIT License",
+				"confidence": 0.7469879518072289
+			}
+		]
+	},
 	{
 		"project": "sigs.k8s.io/yaml",
 		"licenses": [

build.sh

@@ -42,16 +42,29 @@ etcd_build() {
     # Static compilation is useful when etcd is run in a container. $GO_BUILD_FLAGS is OK
     # shellcheck disable=SC2086
     run env "${GO_BUILD_ENV[@]}" go build $GO_BUILD_FLAGS \
+      -trimpath \
       -installsuffix=cgo \
       "-ldflags=${GO_LDFLAGS[*]}" \
       -o="../${out}/etcd" . || return 2
   ) || return 2
 
+  run rm -f "${out}/etcdutl"
+  # shellcheck disable=SC2086
+  (
+    cd ./etcdutl
+    run env GO_BUILD_FLAGS="${GO_BUILD_FLAGS}" "${GO_BUILD_ENV[@]}" go build $GO_BUILD_FLAGS \
+      -trimpath \
+      -installsuffix=cgo \
+      "-ldflags=${GO_LDFLAGS[*]}" \
+      -o="../${out}/etcdutl" . || return 2
+  ) || return 2
+
   run rm -f "${out}/etcdctl"
   # shellcheck disable=SC2086
   (
     cd ./etcdctl
-    run env CGO_ENABLED=0 GO_BUILD_FLAGS="${GO_BUILD_FLAGS}" go build $GO_BUILD_FLAGS \
+    run env GO_BUILD_FLAGS="${GO_BUILD_FLAGS}" "${GO_BUILD_ENV[@]}" go build $GO_BUILD_FLAGS \
+      -trimpath \
       -installsuffix=cgo \
       "-ldflags=${GO_LDFLAGS[*]}" \
       -o="../${out}/etcdctl" . || return 2
@@ -82,6 +95,7 @@ tools_build() {
     run rm -f "${out}/${tool}"
     # shellcheck disable=SC2086
     run env GO_BUILD_FLAGS="${GO_BUILD_FLAGS}" CGO_ENABLED=0 go build ${GO_BUILD_FLAGS} \
+      -trimpath \
       -installsuffix=cgo \
       "-ldflags='${GO_LDFLAGS[*]}'" \
       -o="${out}/${tool}" "./${tool}" || return 2

client/pkg/LICENSE

@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   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
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   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.

client/pkg/fileutil/dir_unix.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows
 // +build !windows
 
 package fileutil

client/pkg/fileutil/dir_windows.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build windows
 // +build windows
 
 package fileutil

client/pkg/fileutil/filereader.go

@@ -0,0 +1,60 @@
+// Copyright 2022 The etcd 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
+//
+//     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 fileutil
+
+import (
+	"bufio"
+	"io"
+	"io/fs"
+	"os"
+)
+
+// FileReader is a wrapper of io.Reader. It also provides file info.
+type FileReader interface {
+	io.Reader
+	FileInfo() (fs.FileInfo, error)
+}
+
+type fileReader struct {
+	*os.File
+}
+
+func NewFileReader(f *os.File) FileReader {
+	return &fileReader{f}
+}
+
+func (fr *fileReader) FileInfo() (fs.FileInfo, error) {
+	return fr.Stat()
+}
+
+// FileBufReader is a wrapper of bufio.Reader. It also provides file info.
+type FileBufReader struct {
+	*bufio.Reader
+	fi fs.FileInfo
+}
+
+func NewFileBufReader(fr FileReader) *FileBufReader {
+	bufReader := bufio.NewReader(fr)
+	fi, err := fr.FileInfo()
+	if err != nil {
+		// This should never happen.
+		panic(err)
+	}
+	return &FileBufReader{bufReader, fi}
+}
+
+func (fbr *FileBufReader) FileInfo() fs.FileInfo {
+	return fbr.fi
+}

client/pkg/fileutil/filereader_test.go

@@ -0,0 +1,44 @@
+// Copyright 2022 The etcd 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
+//
+//     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 fileutil
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFileBufReader(t *testing.T) {
+	f, err := os.CreateTemp(t.TempDir(), "wal")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	fi, err := f.Stat()
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	fbr := NewFileBufReader(NewFileReader(f))
+
+	if !strings.HasPrefix(fbr.FileInfo().Name(), "wal") {
+		t.Errorf("Unexpected file name: %s", fbr.FileInfo().Name())
+	}
+	assert.Equal(t, fi.Size(), fbr.FileInfo().Size())
+	assert.Equal(t, fi.IsDir(), fbr.FileInfo().IsDir())
+	assert.Equal(t, fi.Mode(), fbr.FileInfo().Mode())
+	assert.Equal(t, fi.ModTime(), fbr.FileInfo().ModTime())
+}

client/pkg/fileutil/fileutil.go

@@ -32,7 +32,10 @@ const (
 // IsDirWriteable checks if dir is writable by writing and removing a file
 // to dir. It returns nil if dir is writable.
 func IsDirWriteable(dir string) error {
-	f := filepath.Join(dir, ".touch")
+	f, err := filepath.Abs(filepath.Join(dir, ".touch"))
+	if err != nil {
+		return err
+	}
 	if err := ioutil.WriteFile(f, []byte(""), PrivateFileMode); err != nil {
 		return err
 	}
@@ -41,16 +44,12 @@ func IsDirWriteable(dir string) error {
 
 // TouchDirAll is similar to os.MkdirAll. It creates directories with 0700 permission if any directory
 // does not exists. TouchDirAll also ensures the given directory is writable.
-func TouchDirAll(dir string) error {
+func TouchDirAll(lg *zap.Logger, dir string) error {
 	// If path is already a directory, MkdirAll does nothing and returns nil, so,
 	// first check if dir exist with an expected permission mode.
 	if Exist(dir) {
 		err := CheckDirPermission(dir, PrivateDirMode)
 		if err != nil {
-			lg, _ := zap.NewProduction()
-			if lg == nil {
-				lg = zap.NewExample()
-			}
 			lg.Warn("check file permission", zap.Error(err))
 		}
 	} else {
@@ -67,8 +66,8 @@ func TouchDirAll(dir string) error {
 
 // CreateDirAll is similar to TouchDirAll but returns error
 // if the deepest directory was not empty.
-func CreateDirAll(dir string) error {
-	err := TouchDirAll(dir)
+func CreateDirAll(lg *zap.Logger, dir string) error {
+	err := TouchDirAll(lg, dir)
 	if err == nil {
 		var ns []string
 		ns, err = ReadDir(dir)
@@ -121,7 +120,7 @@ func ZeroToEnd(f *os.File) error {
 // Returns error if dir is empty or exist with a different permission than specified.
 func CheckDirPermission(dir string, perm os.FileMode) error {
 	if !Exist(dir) {
-		return fmt.Errorf("directory %q empty, cannot check permission.", dir)
+		return fmt.Errorf("directory %q empty, cannot check permission", dir)
 	}
 	//check the existing permission on the directory
 	dirInfo, err := os.Stat(dir)
@@ -130,8 +129,40 @@ func CheckDirPermission(dir string, perm os.FileMode) error {
 	}
 	dirMode := dirInfo.Mode().Perm()
 	if dirMode != perm {
-		err = fmt.Errorf("directory %q exist, but the permission is %q. The recommended permission is %q to prevent possible unprivileged access to the data.", dir, dirInfo.Mode(), os.FileMode(PrivateDirMode))
+		err = fmt.Errorf("directory %q exist, but the permission is %q. The recommended permission is %q to prevent possible unprivileged access to the data", dir, dirInfo.Mode(), os.FileMode(PrivateDirMode))
 		return err
 	}
 	return nil
 }
+
+// RemoveMatchFile deletes file if matchFunc is true on an existing dir
+// Returns error if the dir does not exist or remove file fail
+func RemoveMatchFile(lg *zap.Logger, dir string, matchFunc func(fileName string) bool) error {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	if !Exist(dir) {
+		return fmt.Errorf("directory %s does not exist", dir)
+	}
+	fileNames, err := ReadDir(dir)
+	if err != nil {
+		return err
+	}
+	var removeFailedFiles []string
+	for _, fileName := range fileNames {
+		if matchFunc(fileName) {
+			file := filepath.Join(dir, fileName)
+			if err = os.Remove(file); err != nil {
+				removeFailedFiles = append(removeFailedFiles, fileName)
+				lg.Error("remove file failed",
+					zap.String("file", file),
+					zap.Error(err))
+				continue
+			}
+		}
+	}
+	if len(removeFailedFiles) != 0 {
+		return fmt.Errorf("remove file(s) %v error", removeFailedFiles)
+	}
+	return nil
+}

client/pkg/fileutil/fileutil_test.go

@@ -26,6 +26,8 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"go.uber.org/zap/zaptest"
 )
 
 func TestIsDirWriteable(t *testing.T) {
@@ -65,7 +67,7 @@ func TestCreateDirAll(t *testing.T) {
 	defer os.RemoveAll(tmpdir)
 
 	tmpdir2 := filepath.Join(tmpdir, "testdir")
-	if err = CreateDirAll(tmpdir2); err != nil {
+	if err = CreateDirAll(zaptest.NewLogger(t), tmpdir2); err != nil {
 		t.Fatal(err)
 	}
 
@@ -73,7 +75,7 @@ func TestCreateDirAll(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err = CreateDirAll(tmpdir2); err == nil || !strings.Contains(err.Error(), "to be empty, got") {
+	if err = CreateDirAll(zaptest.NewLogger(t), tmpdir2); err == nil || !strings.Contains(err.Error(), "to be empty, got") {
 		t.Fatalf("unexpected error %v", err)
 	}
 }
@@ -184,7 +186,7 @@ func TestDirPermission(t *testing.T) {
 
 	tmpdir2 := filepath.Join(tmpdir, "testpermission")
 	// create a new dir with 0700
-	if err = CreateDirAll(tmpdir2); err != nil {
+	if err = CreateDirAll(zaptest.NewLogger(t), tmpdir2); err != nil {
 		t.Fatal(err)
 	}
 	// check dir permission with mode different than created dir
@@ -192,3 +194,45 @@ func TestDirPermission(t *testing.T) {
 		t.Errorf("expected error, got nil")
 	}
 }
+
+func TestRemoveMatchFile(t *testing.T) {
+	tmpdir := t.TempDir()
+	defer os.RemoveAll(tmpdir)
+	f, err := ioutil.TempFile(tmpdir, "tmp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+	f, err = ioutil.TempFile(tmpdir, "foo.tmp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	err = RemoveMatchFile(zaptest.NewLogger(t), tmpdir, func(fileName string) bool {
+		return strings.HasPrefix(fileName, "tmp")
+	})
+	if err != nil {
+		t.Errorf("expected nil, got error")
+	}
+	fnames, err := ReadDir(tmpdir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(fnames) != 1 {
+		t.Errorf("expected exist 1 files, got %d", len(fnames))
+	}
+
+	f, err = ioutil.TempFile(tmpdir, "tmp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+	err = RemoveMatchFile(zaptest.NewLogger(t), tmpdir, func(fileName string) bool {
+		os.Remove(filepath.Join(tmpdir, fileName))
+		return strings.HasPrefix(fileName, "tmp")
+	})
+	if err == nil {
+		t.Errorf("expected error, got nil")
+	}
+}

client/pkg/fileutil/lock_flock.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows && !plan9 && !solaris
 // +build !windows,!plan9,!solaris
 
 package fileutil

client/pkg/fileutil/lock_linux.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build linux
 // +build linux
 
 package fileutil

client/pkg/fileutil/lock_linux_test.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build linux
 // +build linux
 
 package fileutil

client/pkg/fileutil/lock_solaris.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build solaris
 // +build solaris
 
 package fileutil

client/pkg/fileutil/lock_unix.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows && !plan9 && !solaris && !linux
 // +build !windows,!plan9,!solaris,!linux
 
 package fileutil

client/pkg/fileutil/lock_windows.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build windows
 // +build windows
 
 package fileutil

client/pkg/fileutil/preallocate_darwin.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build darwin
 // +build darwin
 
 package fileutil

client/pkg/fileutil/preallocate_unix.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build linux
 // +build linux
 
 package fileutil

client/pkg/fileutil/preallocate_unsupported.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !linux && !darwin
 // +build !linux,!darwin
 
 package fileutil

client/pkg/fileutil/purge.go

@@ -41,6 +41,12 @@ func purgeFile(lg *zap.Logger, dirname string, suffix string, max uint, interval
 		lg = zap.NewNop()
 	}
 	errC := make(chan error, 1)
+	lg.Info("started to purge file",
+		zap.String("dir", dirname),
+		zap.String("suffix", suffix),
+		zap.Uint("max", max),
+		zap.Duration("interval", interval))
+
 	go func() {
 		if donec != nil {
 			defer close(donec)
@@ -63,14 +69,16 @@ func purgeFile(lg *zap.Logger, dirname string, suffix string, max uint, interval
 				f := filepath.Join(dirname, newfnames[0])
 				l, err := TryLockFile(f, os.O_WRONLY, PrivateFileMode)
 				if err != nil {
+					lg.Warn("failed to lock file", zap.String("path", f), zap.Error(err))
 					break
 				}
 				if err = os.Remove(f); err != nil {
+					lg.Error("failed to remove file", zap.String("path", f), zap.Error(err))
 					errC <- err
 					return
 				}
 				if err = l.Close(); err != nil {
-					lg.Warn("failed to unlock/close", zap.String("path", l.Name()), zap.Error(err))
+					lg.Error("failed to unlock/close", zap.String("path", l.Name()), zap.Error(err))
 					errC <- err
 					return
 				}

client/pkg/fileutil/sync.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !linux && !darwin
 // +build !linux,!darwin
 
 package fileutil

client/pkg/fileutil/sync_darwin.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build darwin
 // +build darwin
 
 package fileutil

client/pkg/fileutil/sync_linux.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build linux
 // +build linux
 
 package fileutil

client/pkg/go.mod

@@ -0,0 +1,10 @@
+module go.etcd.io/etcd/client/pkg/v3
+
+go 1.16
+
+require (
+	github.com/coreos/go-systemd/v22 v22.3.2
+	github.com/stretchr/testify v1.7.0
+	go.uber.org/zap v1.17.0
+	golang.org/x/sys v0.0.0-20210403161142-5e06dd20ab57
+)

client/pkg/go.sum

@@ -0,0 +1,29 @@
+github.com/coreos/go-systemd/v22 v22.3.2 h1:D9/bQk5vlXQFZ6Kwuu6zaiXJ9oTPe68++AzAJc1DzSI=
+github.com/coreos/go-systemd/v22 v22.3.2/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
+go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
+go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4=
+go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
+go.uber.org/zap v1.17.0 h1:MTjgFu6ZLKvY6Pvaqk97GlxNBuMpV4Hy/3P6tRGlI2U=
+go.uber.org/zap v1.17.0/go.mod h1:MXVU+bhUf/A7Xi2HNOnopQOrmycQ5Ih87HtOu4q5SSo=
+golang.org/x/sys v0.0.0-20210403161142-5e06dd20ab57 h1:F5Gozwx4I1xtr/sr/8CFbb57iKi3297KFs0QDbGN60A=
+golang.org/x/sys v0.0.0-20210403161142-5e06dd20ab57/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

client/pkg/logutil/log_level.go

@@ -15,9 +15,6 @@
 package logutil
 
 import (
-	"fmt"
-
-	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 )
 
@@ -25,22 +22,9 @@ var DefaultLogLevel = "info"
 
 // ConvertToZapLevel converts log level string to zapcore.Level.
 func ConvertToZapLevel(lvl string) zapcore.Level {
-	switch lvl {
-	case "debug":
-		return zap.DebugLevel
-	case "info":
-		return zap.InfoLevel
-	case "warn":
-		return zap.WarnLevel
-	case "error":
-		return zap.ErrorLevel
-	case "dpanic":
-		return zap.DPanicLevel
-	case "panic":
-		return zap.PanicLevel
-	case "fatal":
-		return zap.FatalLevel
-	default:
-		panic(fmt.Sprintf("unknown level %q", lvl))
+	var level zapcore.Level
+	if err := level.Set(lvl); err != nil {
+		panic(err)
 	}
+	return level
 }

client/pkg/logutil/zap.go

@@ -21,6 +21,17 @@ import (
 	"go.uber.org/zap/zapcore"
 )
 
+// CreateDefaultZapLogger creates a logger with default zap configuration
+func CreateDefaultZapLogger(level zapcore.Level) (*zap.Logger, error) {
+	lcfg := DefaultZapLoggerConfig
+	lcfg.Level = zap.NewAtomicLevelAt(level)
+	c, err := lcfg.Build()
+	if err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
 // DefaultZapLoggerConfig defines default zap logger configuration.
 var DefaultZapLoggerConfig = zap.Config{
 	Level: zap.NewAtomicLevelAt(ConvertToZapLevel(DefaultLogLevel)),

client/pkg/logutil/zap_journal.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows
 // +build !windows
 
 package logutil
@@ -24,7 +25,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"go.etcd.io/etcd/pkg/v3/systemd"
+	"go.etcd.io/etcd/client/pkg/v3/systemd"
 
 	"github.com/coreos/go-systemd/v22/journal"
 	"go.uber.org/zap/zapcore"

client/pkg/logutil/zap_journal_test.go

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows
 // +build !windows
 
 package logutil

client/pkg/srv/srv.go

@@ -21,7 +21,7 @@ import (
 	"net/url"
 	"strings"
 
-	"go.etcd.io/etcd/pkg/v3/types"
+	"go.etcd.io/etcd/client/pkg/v3/types"
 )
 
 var (

client/pkg/srv/srv_test.go

@@ -22,7 +22,7 @@ import (
 	"strings"
 	"testing"
 
-	"go.etcd.io/etcd/pkg/v3/testutil"
+	"go.etcd.io/etcd/client/pkg/v3/testutil"
 )
 
 func notFoundErr(service, proto, domain string) error {
@@ -228,10 +228,10 @@ func TestSRVDiscover(t *testing.T) {
 			[]*net.SRV{
 				{Target: "a.example.com", Port: 2480},
 				{Target: "b.example.com", Port: 2480},
-				{Target: "c.example.com", Port: 2480},
+				{Target: "c.example.com.", Port: 2480},
 			},
 			[]*net.SRV{},
-			[]string{"https://a.example.com:2480", "https://b.example.com:2480", "https://c.example.com:2480"},
+			[]string{"https://a.example.com:2480", "https://b.example.com:2480", "https://c.example.com.:2480"},
 			false,
 		},
 	}

client/pkg/testutil/leak.go

@@ -16,22 +16,23 @@ import (
 	"time"
 )
 
+// TODO: Replace with https://github.com/uber-go/goleak.
+
 /*
 CheckLeakedGoroutine verifies tests do not leave any leaky
 goroutines. It returns true when there are goroutines still
 running(leaking) after all tests.
 
-	import "go.etcd.io/etcd/pkg/v3/testutil"
+	import "go.etcd.io/etcd/client/pkg/v3/testutil"
 
 	func TestMain(m *testing.M) {
 		testutil.MustTestMainWithLeakDetection(m)
 	}
 
 	func TestSample(t *testing.T) {
-		defer testutil.AfterTest(t)
+		RegisterLeakDetection(t)
 		...
 	}
-
 */
 func CheckLeakedGoroutine() bool {
 	gs := interestingGoroutines()
@@ -59,6 +60,7 @@ func CheckLeakedGoroutine() bool {
 func CheckAfterTest(d time.Duration) error {
 	http.DefaultTransport.(*http.Transport).CloseIdleConnections()
 	var bad string
+	// Presence of these goroutines causes immediate test failure.
 	badSubstring := map[string]string{
 		").writeLoop(": "a Transport",
 		"created by net/http/httptest.(*Server).Start": "an httptest.Server",
@@ -74,28 +76,47 @@ func CheckAfterTest(d time.Duration) error {
 	begin := time.Now()
 	for time.Since(begin) < d {
 		bad = ""
-		stacks = strings.Join(interestingGoroutines(), "\n\n")
+		goroutines := interestingGoroutines()
+		if len(goroutines) == 0 {
+			return nil
+		}
+		stacks = strings.Join(goroutines, "\n\n")
+
 		for substr, what := range badSubstring {
 			if strings.Contains(stacks, substr) {
 				bad = what
 			}
 		}
-		if bad == "" {
-			return nil
-		}
-		// Bad stuff found, but goroutines might just still be
+		// Undesired goroutines found, but goroutines might just still be
 		// shutting down, so give it some time.
+		runtime.Gosched()
 		time.Sleep(50 * time.Millisecond)
 	}
 	return fmt.Errorf("appears to have leaked %s:\n%s", bad, stacks)
 }
 
-// AfterTest is meant to run in a defer that executes after a test completes.
+// RegisterLeakDetection is a convenient way to register before-and-after code to a test.
+// If you execute RegisterLeakDetection, you don't need to explicitly register AfterTest.
+func RegisterLeakDetection(t TB) {
+	if err := CheckAfterTest(10 * time.Millisecond); err != nil {
+		t.Skip("Found leaked goroutined BEFORE test", err)
+		return
+	}
+	t.Cleanup(func() {
+		afterTest(t)
+	})
+}
+
+// afterTest is meant to run in a defer that executes after a test completes.
 // It will detect common goroutine leaks, retrying in case there are goroutines
 // not synchronously torn down, and fail the test if any goroutines are stuck.
-func AfterTest(t *testing.T) {
-	if err := CheckAfterTest(300 * time.Millisecond); err != nil {
-		t.Errorf("Test %v", err)
+func afterTest(t TB) {
+	// If test-failed the leaked goroutines list is hidding the real
+	// source of problem.
+	if !t.Failed() {
+		if err := CheckAfterTest(1 * time.Second); err != nil {
+			t.Errorf("Test %v", err)
+		}
 	}
 }
 
@@ -119,13 +140,15 @@ func interestingGoroutines() (gs []string) {
 			strings.Contains(stack, "created by testing.(*T).Run") ||
 			strings.Contains(stack, "testing.Main(") ||
 			strings.Contains(stack, "runtime.goexit") ||
-			strings.Contains(stack, "go.etcd.io/etcd/pkg/v3/testutil.interestingGoroutines") ||
-			strings.Contains(stack, "go.etcd.io/etcd/pkg/v3/logutil.(*MergeLogger).outputLoop") ||
+			strings.Contains(stack, "go.etcd.io/etcd/client/pkg/v3/testutil.interestingGoroutines") ||
+			strings.Contains(stack, "go.etcd.io/etcd/client/pkg/v3/logutil.(*MergeLogger).outputLoop") ||
 			strings.Contains(stack, "github.com/golang/glog.(*loggingT).flushDaemon") ||
 			strings.Contains(stack, "created by runtime.gc") ||
 			strings.Contains(stack, "created by text/template/parse.lex") ||
 			strings.Contains(stack, "runtime.MHeap_Scavenger") ||
-			strings.Contains(stack, "rcrypto/internal/boring.(*PublicKeyRSA).finalize") {
+			strings.Contains(stack, "rcrypto/internal/boring.(*PublicKeyRSA).finalize") ||
+			strings.Contains(stack, "net.(*netFD).Close(") ||
+			strings.Contains(stack, "testing.(*T).Run") {
 			continue
 		}
 		gs = append(gs, stack)

client/pkg/testutil/leak_test.go

@@ -35,7 +35,7 @@ func TestMain(m *testing.M) {
 
 func TestSample(t *testing.T) {
 	SkipTestIfShortMode(t, "Counting leaked routines is disabled in --short tests")
-	defer AfterTest(t)
+	defer afterTest(t)
 	ranSample = true
 	for range make([]struct{}, 100) {
 		go func() {

client/pkg/testutil/testingtb.go

@@ -0,0 +1,130 @@
+// Copyright 2021 The etcd 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
+//
+//     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 testutil
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+)
+
+// TB is a subset of methods of testing.TB interface.
+// We cannot implement testing.TB due to protection, so we expose this simplified interface.
+type TB interface {
+	Cleanup(func())
+	Error(args ...interface{})
+	Errorf(format string, args ...interface{})
+	Fail()
+	FailNow()
+	Failed() bool
+	Fatal(args ...interface{})
+	Fatalf(format string, args ...interface{})
+	Logf(format string, args ...interface{})
+	Name() string
+	TempDir() string
+	Helper()
+	Skip(args ...interface{})
+}
+
+// NewTestingTBProthesis creates a fake variant of testing.TB implementation.
+// It's supposed to be used in contexts were real testing.T is not provided,
+// e.g. in 'examples'.
+//
+// The `closef` goroutine should get executed when tb will not be needed any longer.
+//
+// The provided implementation is NOT thread safe (Cleanup() method).
+func NewTestingTBProthesis(name string) (tb TB, closef func()) {
+	testtb := &testingTBProthesis{name: name}
+	return testtb, testtb.close
+}
+
+type testingTBProthesis struct {
+	name     string
+	failed   bool
+	cleanups []func()
+}
+
+func (t *testingTBProthesis) Helper() {
+	// Ignored
+}
+
+func (t *testingTBProthesis) Skip(args ...interface{}) {
+	t.Log(append([]interface{}{"Skipping due to: "}, args...))
+}
+
+func (t *testingTBProthesis) Cleanup(f func()) {
+	t.cleanups = append(t.cleanups, f)
+}
+
+func (t *testingTBProthesis) Error(args ...interface{}) {
+	log.Println(args...)
+	t.Fail()
+}
+
+func (t *testingTBProthesis) Errorf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+	t.Fail()
+}
+
+func (t *testingTBProthesis) Fail() {
+	t.failed = true
+}
+
+func (t *testingTBProthesis) FailNow() {
+	t.failed = true
+	panic("FailNow() called")
+}
+
+func (t *testingTBProthesis) Failed() bool {
+	return t.failed
+}
+
+func (t *testingTBProthesis) Fatal(args ...interface{}) {
+	log.Fatalln(args...)
+}
+
+func (t *testingTBProthesis) Fatalf(format string, args ...interface{}) {
+	log.Fatalf(format, args...)
+}
+
+func (t *testingTBProthesis) Logf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+}
+
+func (t *testingTBProthesis) Log(args ...interface{}) {
+	log.Println(args...)
+}
+
+func (t *testingTBProthesis) Name() string {
+	return t.name
+}
+
+func (t *testingTBProthesis) TempDir() string {
+	dir, err := ioutil.TempDir("", t.name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.cleanups = append([]func(){func() {
+		t.Logf("Cleaning UP: %v", dir)
+		os.RemoveAll(dir)
+	}}, t.cleanups...)
+	return dir
+}
+
+func (t *testingTBProthesis) close() {
+	for i := len(t.cleanups) - 1; i >= 0; i-- {
+		t.cleanups[i]()
+	}
+}

client/pkg/testutil/testutil.go

@@ -53,8 +53,9 @@ func MustNewURL(t *testing.T, s string) *url.URL {
 func FatalStack(t *testing.T, s string) {
 	stackTrace := make([]byte, 1024*1024)
 	n := runtime.Stack(stackTrace, true)
+	t.Errorf("---> Test failed: %s", s)
 	t.Error(string(stackTrace[:n]))
-	t.Fatalf(s)
+	t.Fatal(s)
 }
 
 // ConditionFunc returns true when a condition is met.
@@ -84,7 +85,7 @@ func Poll(interval time.Duration, timeout time.Duration, condition ConditionFunc
 	}
 }
 
-func SkipTestIfShortMode(t testing.TB, reason string) {
+func SkipTestIfShortMode(t TB, reason string) {
 	if t != nil {
 		t.Helper()
 		if testing.Short() {

client/pkg/tlsutil/cipher_suites.go

@@ -14,7 +14,10 @@
 
 package tlsutil
 
-import "crypto/tls"
+import (
+	"crypto/tls"
+	"fmt"
+)
 
 // GetCipherSuite returns the corresponding cipher suite,
 // and boolean value if it is supported.
@@ -37,3 +40,17 @@ func GetCipherSuite(s string) (uint16, bool) {
 	}
 	return 0, false
 }
+
+// GetCipherSuites returns list of corresponding cipher suite IDs.
+func GetCipherSuites(ss []string) ([]uint16, error) {
+	cs := make([]uint16, len(ss))
+	for i, s := range ss {
+		var ok bool
+		cs[i], ok = GetCipherSuite(s)
+		if !ok {
+			return nil, fmt.Errorf("unexpected TLS cipher suite %q", s)
+		}
+	}
+
+	return cs, nil
+}

client/pkg/transport/keepalive_listener.go

@@ -21,26 +21,29 @@ import (
 	"time"
 )
 
-type keepAliveConn interface {
-	SetKeepAlive(bool) error
-	SetKeepAlivePeriod(d time.Duration) error
-}
-
 // NewKeepAliveListener returns a listener that listens on the given address.
 // Be careful when wrap around KeepAliveListener with another Listener if TLSInfo is not nil.
 // Some pkgs (like go/http) might expect Listener to return TLSConn type to start TLS handshake.
 // http://tldp.org/HOWTO/TCP-Keepalive-HOWTO/overview.html
+//
+// Note(ahrtr):
+// only `net.TCPConn` supports `SetKeepAlive` and `SetKeepAlivePeriod`
+// by default, so if you want to wrap multiple layers of net.Listener,
+// the `keepaliveListener` should be the one which is closest to the
+// original `net.Listener` implementation, namely `TCPListener`.
 func NewKeepAliveListener(l net.Listener, scheme string, tlscfg *tls.Config) (net.Listener, error) {
+	kal := &keepaliveListener{
+		Listener: l,
+	}
+
 	if scheme == "https" {
 		if tlscfg == nil {
 			return nil, fmt.Errorf("cannot listen on TLS for given listener: KeyFile and CertFile are not presented")
 		}
-		return newTLSKeepaliveListener(l, tlscfg), nil
+		return newTLSKeepaliveListener(kal, tlscfg), nil
 	}
 
-	return &keepaliveListener{
-		Listener: l,
-	}, nil
+	return kal, nil
 }
 
 type keepaliveListener struct{ net.Listener }
@@ -50,13 +53,43 @@ func (kln *keepaliveListener) Accept() (net.Conn, error) {
 	if err != nil {
 		return nil, err
 	}
-	kac := c.(keepAliveConn)
+
+	kac, err := createKeepaliveConn(c)
+	if err != nil {
+		return nil, fmt.Errorf("create keepalive connection failed, %w", err)
+	}
 	// detection time: tcp_keepalive_time + tcp_keepalive_probes + tcp_keepalive_intvl
 	// default on linux:  30 + 8 * 30
 	// default on osx:    30 + 8 * 75
-	kac.SetKeepAlive(true)
-	kac.SetKeepAlivePeriod(30 * time.Second)
-	return c, nil
+	if err := kac.SetKeepAlive(true); err != nil {
+		return nil, fmt.Errorf("SetKeepAlive failed, %w", err)
+	}
+	if err := kac.SetKeepAlivePeriod(30 * time.Second); err != nil {
+		return nil, fmt.Errorf("SetKeepAlivePeriod failed, %w", err)
+	}
+	return kac, nil
+}
+
+func createKeepaliveConn(c net.Conn) (*keepAliveConn, error) {
+	tcpc, ok := c.(*net.TCPConn)
+	if !ok {
+		return nil, ErrNotTCP
+	}
+	return &keepAliveConn{tcpc}, nil
+}
+
+type keepAliveConn struct {
+	*net.TCPConn
+}
+
+// SetKeepAlive sets keepalive
+func (l *keepAliveConn) SetKeepAlive(doKeepAlive bool) error {
+	return l.TCPConn.SetKeepAlive(doKeepAlive)
+}
+
+// SetKeepAlivePeriod sets keepalive period
+func (l *keepAliveConn) SetKeepAlivePeriod(d time.Duration) error {
+	return l.TCPConn.SetKeepAlivePeriod(d)
 }
 
 // A tlsKeepaliveListener implements a network listener (net.Listener) for TLS connections.
@@ -72,12 +105,6 @@ func (l *tlsKeepaliveListener) Accept() (c net.Conn, err error) {
 	if err != nil {
 		return
 	}
-	kac := c.(keepAliveConn)
-	// detection time: tcp_keepalive_time + tcp_keepalive_probes + tcp_keepalive_intvl
-	// default on linux:  30 + 8 * 30
-	// default on osx:    30 + 8 * 75
-	kac.SetKeepAlive(true)
-	kac.SetKeepAlivePeriod(30 * time.Second)
 	c = tls.Server(c, l.config)
 	return c, nil
 }

client/pkg/transport/keepalive_listener_test.go

@@ -40,6 +40,9 @@ func TestNewKeepAliveListener(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unexpected Accept error: %v", err)
 	}
+	if _, ok := conn.(*keepAliveConn); !ok {
+		t.Fatalf("Unexpected conn type: %T, wanted *keepAliveConn", conn)
+	}
 	conn.Close()
 	ln.Close()
 

client/pkg/transport/limit_listen.go

@@ -63,6 +63,9 @@ func (l *limitListenerConn) Close() error {
 	return err
 }
 
+// SetKeepAlive sets keepalive
+//
+// Deprecated: use (*keepAliveConn) SetKeepAlive instead.
 func (l *limitListenerConn) SetKeepAlive(doKeepAlive bool) error {
 	tcpc, ok := l.Conn.(*net.TCPConn)
 	if !ok {
@@ -71,6 +74,9 @@ func (l *limitListenerConn) SetKeepAlive(doKeepAlive bool) error {
 	return tcpc.SetKeepAlive(doKeepAlive)
 }
 
+// SetKeepAlivePeriod sets keepalive period
+//
+// Deprecated: use (*keepAliveConn) SetKeepAlivePeriod instead.
 func (l *limitListenerConn) SetKeepAlivePeriod(d time.Duration) error {
 	tcpc, ok := l.Conn.(*net.TCPConn)
 	if !ok {

client/pkg/transport/listener.go

@@ -15,6 +15,7 @@
 package transport
 
 import (
+	"context"
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
@@ -31,26 +32,87 @@ import (
 	"strings"
 	"time"
 
-	"go.etcd.io/etcd/pkg/v3/fileutil"
-	"go.etcd.io/etcd/pkg/v3/tlsutil"
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/client/pkg/v3/tlsutil"
 
 	"go.uber.org/zap"
 )
 
 // NewListener creates a new listner.
 func NewListener(addr, scheme string, tlsinfo *TLSInfo) (l net.Listener, err error) {
-	if l, err = newListener(addr, scheme); err != nil {
-		return nil, err
-	}
-	return wrapTLS(scheme, tlsinfo, l)
+	return newListener(addr, scheme, WithTLSInfo(tlsinfo))
 }
 
-func newListener(addr string, scheme string) (net.Listener, error) {
+// NewListenerWithOpts creates a new listener which accpets listener options.
+func NewListenerWithOpts(addr, scheme string, opts ...ListenerOption) (net.Listener, error) {
+	return newListener(addr, scheme, opts...)
+}
+
+func newListener(addr, scheme string, opts ...ListenerOption) (net.Listener, error) {
 	if scheme == "unix" || scheme == "unixs" {
 		// unix sockets via unix://laddr
 		return NewUnixListener(addr)
 	}
-	return net.Listen("tcp", addr)
+
+	lnOpts := newListenOpts(opts...)
+
+	switch {
+	case lnOpts.IsSocketOpts():
+		// new ListenConfig with socket options.
+		config, err := newListenConfig(lnOpts.socketOpts)
+		if err != nil {
+			return nil, err
+		}
+		lnOpts.ListenConfig = config
+		// check for timeout
+		fallthrough
+	case lnOpts.IsTimeout(), lnOpts.IsSocketOpts():
+		// timeout listener with socket options.
+		ln, err := newKeepAliveListener(&lnOpts.ListenConfig, addr)
+		if err != nil {
+			return nil, err
+		}
+		lnOpts.Listener = &rwTimeoutListener{
+			Listener:     ln,
+			readTimeout:  lnOpts.readTimeout,
+			writeTimeout: lnOpts.writeTimeout,
+		}
+	case lnOpts.IsTimeout():
+		ln, err := newKeepAliveListener(nil, addr)
+		if err != nil {
+			return nil, err
+		}
+		lnOpts.Listener = &rwTimeoutListener{
+			Listener:     ln,
+			readTimeout:  lnOpts.readTimeout,
+			writeTimeout: lnOpts.writeTimeout,
+		}
+	default:
+		ln, err := newKeepAliveListener(nil, addr)
+		if err != nil {
+			return nil, err
+		}
+		lnOpts.Listener = ln
+	}
+
+	//  only skip if not passing TLSInfo
+	if lnOpts.skipTLSInfoCheck && !lnOpts.IsTLS() {
+		return lnOpts.Listener, nil
+	}
+	return wrapTLS(scheme, lnOpts.tlsInfo, lnOpts.Listener)
+}
+
+func newKeepAliveListener(cfg *net.ListenConfig, addr string) (ln net.Listener, err error) {
+	if cfg != nil {
+		ln, err = cfg.Listen(context.TODO(), "tcp", addr)
+	} else {
+		ln, err = net.Listen("tcp", addr)
+	}
+	if err != nil {
+		return
+	}
+
+	return NewKeepAliveListener(ln, "tcp", nil)
 }
 
 func wrapTLS(scheme string, tlsinfo *TLSInfo, l net.Listener) (net.Listener, error) {
@@ -63,9 +125,28 @@ func wrapTLS(scheme string, tlsinfo *TLSInfo, l net.Listener) (net.Listener, err
 	return newTLSListener(l, tlsinfo, checkSAN)
 }
 
+func newListenConfig(sopts *SocketOpts) (net.ListenConfig, error) {
+	lc := net.ListenConfig{}
+	if sopts != nil {
+		ctls := getControls(sopts)
+		if len(ctls) > 0 {
+			lc.Control = ctls.Control
+		}
+	}
+	return lc, nil
+}
+
 type TLSInfo struct {
-	CertFile            string
-	KeyFile             string
+	// CertFile is the _server_ cert, it will also be used as a _client_ certificate if ClientCertFile is empty
+	CertFile string
+	// KeyFile is the key for the CertFile
+	KeyFile string
+	// ClientCertFile is a _client_ cert for initiating connections when ClientCertAuth is defined. If ClientCertAuth
+	// is true but this value is empty, the CertFile will be used instead.
+	ClientCertFile string
+	// ClientKeyFile is the key for the ClientCertFile
+	ClientKeyFile string
+
 	TrustedCAFile       string
 	ClientCertAuth      bool
 	CRLFile             string
@@ -107,7 +188,7 @@ type TLSInfo struct {
 }
 
 func (info TLSInfo) String() string {
-	return fmt.Sprintf("cert = %s, key = %s, trusted-ca = %s, client-cert-auth = %v, crl-file = %s", info.CertFile, info.KeyFile, info.TrustedCAFile, info.ClientCertAuth, info.CRLFile)
+	return fmt.Sprintf("cert = %s, key = %s, client-cert=%s, client-key=%s, trusted-ca = %s, client-cert-auth = %v, crl-file = %s", info.CertFile, info.KeyFile, info.ClientCertFile, info.ClientKeyFile, info.TrustedCAFile, info.ClientCertAuth, info.CRLFile)
 }
 
 func (info TLSInfo) Empty() bool {
@@ -124,7 +205,7 @@ func SelfCert(lg *zap.Logger, dirpath string, hosts []string, selfSignedCertVali
 		)
 		return
 	}
-	err = fileutil.TouchDirAll(dirpath)
+	err = fileutil.TouchDirAll(lg, dirpath)
 	if err != nil {
 		if info.Logger != nil {
 			info.Logger.Warn(
@@ -135,13 +216,21 @@ func SelfCert(lg *zap.Logger, dirpath string, hosts []string, selfSignedCertVali
 		return
 	}
 
-	certPath := filepath.Join(dirpath, "cert.pem")
-	keyPath := filepath.Join(dirpath, "key.pem")
+	certPath, err := filepath.Abs(filepath.Join(dirpath, "cert.pem"))
+	if err != nil {
+		return
+	}
+	keyPath, err := filepath.Abs(filepath.Join(dirpath, "key.pem"))
+	if err != nil {
+		return
+	}
 	_, errcert := os.Stat(certPath)
 	_, errkey := os.Stat(keyPath)
 	if errcert == nil && errkey == nil {
 		info.CertFile = certPath
 		info.KeyFile = keyPath
+		info.ClientCertFile = certPath
+		info.ClientKeyFile = keyPath
 		info.selfCert = true
 		return
 	}
@@ -278,6 +367,17 @@ func (info TLSInfo) baseConfig() (*tls.Config, error) {
 		return nil, err
 	}
 
+	// Perform prevalidation of client cert and key if either are provided. This makes sure we crash before accepting any connections.
+	if (info.ClientKeyFile == "") != (info.ClientCertFile == "") {
+		return nil, fmt.Errorf("ClientKeyFile and ClientCertFile must both be present or both absent: key: %v, cert: %v]", info.ClientKeyFile, info.ClientCertFile)
+	}
+	if info.ClientCertFile != "" {
+		_, err := tlsutil.NewCert(info.ClientCertFile, info.ClientKeyFile, info.parseFunc)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	cfg := &tls.Config{
 		MinVersion: tls.VersionTLS12,
 		ServerName: info.ServerName,
@@ -342,13 +442,17 @@ func (info TLSInfo) baseConfig() (*tls.Config, error) {
 		return cert, err
 	}
 	cfg.GetClientCertificate = func(unused *tls.CertificateRequestInfo) (cert *tls.Certificate, err error) {
-		cert, err = tlsutil.NewCert(info.CertFile, info.KeyFile, info.parseFunc)
+		certfile, keyfile := info.CertFile, info.KeyFile
+		if info.ClientCertFile != "" {
+			certfile, keyfile = info.ClientCertFile, info.ClientKeyFile
+		}
+		cert, err = tlsutil.NewCert(certfile, keyfile, info.parseFunc)
 		if os.IsNotExist(err) {
 			if info.Logger != nil {
 				info.Logger.Warn(
 					"failed to find client cert files",
-					zap.String("cert-file", info.CertFile),
-					zap.String("key-file", info.KeyFile),
+					zap.String("cert-file", certfile),
+					zap.String("key-file", keyfile),
 					zap.Error(err),
 				)
 			}
@@ -356,8 +460,8 @@ func (info TLSInfo) baseConfig() (*tls.Config, error) {
 			if info.Logger != nil {
 				info.Logger.Warn(
 					"failed to create client certificate",
-					zap.String("cert-file", info.CertFile),
-					zap.String("key-file", info.KeyFile),
+					zap.String("cert-file", certfile),
+					zap.String("key-file", keyfile),
 					zap.Error(err),
 				)
 			}
@@ -383,6 +487,10 @@ func (info TLSInfo) ServerConfig() (*tls.Config, error) {
 		return nil, err
 	}
 
+	if info.Logger == nil {
+		info.Logger = zap.NewNop()
+	}
+
 	cfg.ClientAuth = tls.NoClientCert
 	if info.TrustedCAFile != "" || info.ClientCertAuth {
 		cfg.ClientAuth = tls.RequireAndVerifyClientCert
@@ -390,6 +498,8 @@ func (info TLSInfo) ServerConfig() (*tls.Config, error) {
 
 	cs := info.cafiles()
 	if len(cs) > 0 {
+		info.Logger.Info("Loading cert pool", zap.Strings("cs", cs),
+			zap.Any("tlsinfo", info))
 		cp, err := tlsutil.NewCertPool(cs)
 		if err != nil {
 			return nil, err