diff --git a/tests/robustness/README.md b/tests/robustness/README.md index e47e61d15..b1ea6bae6 100644 --- a/tests/robustness/README.md +++ b/tests/robustness/README.md @@ -39,7 +39,7 @@ The purpose of these tests is to rigorously validate that etcd maintains its [KV ## How Robustness Tests Work -Robustness tests compare etcd cluster behavior against a simplified model of its expected behavior. +Robustness tests compare the etcd cluster behavior against a simplified model of its expected behavior. These tests cover various scenarios, including: * **Different etcd cluster setups:** Cluster sizes, configurations, and deployment topologies. @@ -52,8 +52,8 @@ These tests cover various scenarios, including: 2. **Traffic and Failures:** Client traffic is generated and sent to the cluster while failures are injected. 3. **History Collection:** All client operations and their results are recorded. 4. **Validation:** The collected history is validated against the etcd model and a set of validators to ensure consistency and correctness. -5. **Report Generation:** If a failure is detected and a detailed report is generated to help diagnose the issue. - This report includes information about the client operations, etcd data directories. +5. **Report Generation:** If a failure is detected then a detailed report is generated to help diagnose the issue. + This report includes information about the client operations and etcd data directories. ## Key Concepts @@ -96,26 +96,25 @@ Etcd provides strict serializability for KV operations and eventual consistency make gofail-disable ``` 2. Run the tests - ```bash make test-robustness ``` - Optionally you can pass environment variables: + Optionally, you can pass environment variables: * `GO_TEST_FLAGS` - to pass additional arguments to `go test`. It is recommended to run tests multiple times with failfast enabled. this can be done by setting `GO_TEST_FLAGS='--count=100 --failfast'`. * `EXPECT_DEBUG=true` - to get logs from the cluster. - * `RESULTS_DIR` - to change location where results report will be saved. + * `RESULTS_DIR` - to change the location where the results report will be saved. * `PERSIST_RESULTS` - to persist the results report of the test. By default this will not be persisted in the case of a successful run. ## Re-evaluate existing report Robustness test validation is constantly changing and improving. -Errors in etcd model could be causing false positives, which makes the ability to re-evaluate the reports after we fix the issue important. +Errors in the etcd model could be causing false positives, which makes the ability to re-evaluate the reports after we fix the issue important. > Note: Robustness test report format is not stable, and it's expected that not all old reports can be re-evaluated using the newest version. -1. Identify location of the robustness test report. +1. Identify the location of the robustness test report. > Note: By default robustness test report is only generated for failed test. @@ -124,7 +123,7 @@ Errors in etcd model could be causing false positives, which makes the ability t logger.go:146: 2024-04-08T09:45:27.734+0200 INFO Saving robustness test report {"path": "/tmp/TestRobustnessExploratory_Etcd_HighTraffic_ClusterOfSize1"} ``` - * **For remote runs on CI:** you need to go to the [Prow Dashboard](https://prow.k8s.io/job-history/gs/kubernetes-jenkins/logs/ci-etcd-robustness-amd64), go to a build, download one of the Artifacts (`artifacts/results.zip`), and extract it locally. + * **For remote runs on CI:** you need to go to the [Prow Dashboard](https://testgrid.k8s.io/sig-etcd-robustness#Summary), go to a build, download one of the Artifacts (`artifacts/results.zip`), and extract it locally. ![Prow job run page](readme-images/prow_job.png) @@ -144,14 +143,14 @@ Errors in etcd model could be causing false positives, which makes the ability t The `testdata` directory can contain multiple robustness test reports. The name of the report directory doesn't matter, as long as it's unique to prevent clashing with reports already present in `testdata` directory. - For example path for `history.html` file could look like `$REPO_ROOT/tests/robustness/testdata/v3.5_failure_24_April/history.html`. + For example, the path for `history.html` file could look like `$REPO_ROOT/tests/robustness/testdata/v3.5_failure_24_April/history.html`. 3. Run `make test-robustness-reports` to validate all reports in the `testdata` directory. ## Analysing failure -If robustness tests fails we want to analyse the report to confirm if the issue is on etcd side. Location of the directory with the report -is mentioned `Saving robustness test report` log. Logs from report generation should look like: +If robustness tests fail, we want to analyse the report to confirm if the issue is on etcd side. The location of the directory with the report +is mentioned in the `Saving robustness test report` log. Logs from report generation should look like: ``` logger.go:146: 2024-05-08T10:42:54.429+0200 INFO Saving robustness test report {"path": "/tmp/TestRobustnessRegression_Issue14370/1715157774429416550"} logger.go:146: 2024-05-08T10:42:54.429+0200 INFO Saving member data dir {"member": "TestRobustnessRegressionIssue14370-test-0", "path": "/tmp/TestRobustnessRegression_Issue14370/1715157774429416550/server-TestRobustnessRegressionIssue14370-test-0"} @@ -178,21 +177,21 @@ is mentioned `Saving robustness test report` log. Logs from report generation sh logger.go:146: 2024-05-08T10:42:54.441+0200 INFO Saving visualization {"path": "/tmp/TestRobustnessRegression_Issue14370/1715157774429416550/history.html"} ``` -Report follows the hierarchy: +The report follows the hierarchy: * `server-*` - etcd server data directories, can be used to verify disk/memory corruption. * `member` * `wal` - Write Ahead Log (WAL) directory, that can be analysed using `etcd-dump-logs` command line tool available in `tools` directory. * `snap` - Snapshot directory, includes the bbolt database file `db`, that can be analysed using `etcd-dump-db` command line tool available in `tools` directory. * `client-*` - Client request and response dumps in json format. - * `watch.jon` - Watch requests and responses, can be used to validate [watch API guarantees]. + * `watch.json` - Watch requests and responses, can be used to validate [watch API guarantees]. * `operations.json` - KV operation history * `history.html` - Visualization of KV operation history, can be used to validate [KV API guarantees]. -### Example analysis of linearization issue +### Example analysis of a linearization issue Let's reproduce and analyse robustness test report for issue [#14370]. To reproduce the issue by yourself run `make test-robustness-issue14370`. -After a couple of tries robustness tests should fail with a log `Linearization failed` and save report locally. +After a couple of tries robustness tests should fail with a log `Linearization failed` and save the report locally. Example: ``` @@ -211,14 +210,14 @@ Jump to the error in linearization by clicking `[ jump to first error ]` on the You should see a graph similar to the one on the image below. ![issue14370](readme-images/issue14370.png) -Last correct request (connected with grey line) is a `Put` request that succeeded and got revision `168`. +The last correct request (connected with the grey line) is a `Put` request that succeeded and got revision `168`. All following requests are invalid (connected with red line) as they have revision `167`. -Etcd guarantee that revision is non-decreasing, so this shows a bug in etcd as there is no way revision should decrease. -This is consistent with the root cause of [#14370] as it was issue with process crash causing last write to be lost. +Etcd guarantees that revision is non-decreasing, so this shows a bug in etcd as there is no way revision should decrease. +This is consistent with the root cause of [#14370] as it was an issue with the process crash causing the last write to be lost. [#14370]: https://github.com/etcd-io/etcd/issues/14370 -### Example analysis of watch issue +### Example analysis of a watch issue Let's reproduce and analyse robustness test report for issue [#15271]. To reproduce the issue by yourself run `make test-robustness-issue15271`. @@ -236,22 +235,24 @@ Example: ``` Watch issues are easiest to analyse by reading the recorded watch history. -Watch history is recorded for each client separated in different subdirectory under `/tmp/TestRobustnessRegression_Issue15271/1715158215866033806` -Open `watch.json` for client mentioned in log `Broke watch guarantee`. + +Watch history is recorded for each client separated in different subdirectory under `/tmp/TestRobustnessRegression_Issue15271/1715158215866033806`. + +Open `watch.json` for the client mentioned in the log `Broke watch guarantee`. For client `4` that broke the watch guarantee open `/tmp/TestRobustnessRegression_Issue15271/1715158215866033806/client-4/watch.json`. -Each line consists of json blob corresponding to single watch request sent by client. -Look for events with `Revision` equal to revision mentioned in the first log with `Broke watch guarantee`, in this case look for `"Revision":3,`. +Each line consists of json blob corresponding to a single watch request sent by the client. +Look for events with `Revision` equal to revision mentioned in the first log with `Broke watch guarantee`, in this case, look for `"Revision":3,`. You should see watch responses where the `Revision` decreases like ones below: ``` {"Events":[{"Type":"put-operation","Key":"key5","Value":{"Value":"793","Hash":0},"Revision":799,"IsCreate":false,"PrevValue":null}],"IsProgressNotify":false,"Revision":799,"Time":3202907249,"Error":""} {"Events":[{"Type":"put-operation","Key":"key4","Value":{"Value":"1","Hash":0},"Revision":3,"IsCreate":true,"PrevValue":null}, ... ``` -Up to the first response the `Revision` of events only increased up to a value of `799`. +Up to the first response, the `Revision` of events only increased up to a value of `799`. However, the following line includes an event with `Revision` equal `3`. -If you follow the `revision` throughout the file you should notice that watch replayed revisions second time. +If you follow the `revision` throughout the file you should notice that watch replayed revisions for a second time. This is incorrect and breaks `Ordered` [watch API guarantees]. -This is consistent with the root cause of [#14370] where member reconnecting to cluster will resend revisions. +This is consistent with the root cause of [#14370] where the member reconnecting to cluster will resend revisions. [#15271]: https://github.com/etcd-io/etcd/issues/15271