opendev/elastic-recheck
Code Issues Proposed changes
30ba85c486
elastic-recheck/README.rst
Joe Gordon c507fa1892 Cleanup and clarify README 
* Clarify what elastic-recheck does. Initially the primary goal was to
  report back to gerrit, but we are using elastic-recheck for much more
  then that now, so update docs to reflect that.
* Remove section on dependencies, it was used before we had a proper
  requirements file.
* Remove references to adding the resolved_at option, as that is now
  implemented

Change-Id: I6aa55bdf02174f13d86ad3309f5ad53110dc647d
2013-12-13 17:50:36 +01:00

3.3 KiB
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elastic-recheck

"Use ElasticSearch to classify OpenStack gate failures"

Idea

Identifying the specific bug that is causing a transient error in the gate is very hard. Just identifying which tempest test failed is not enough because a single bug can potentially cause multiple tempest tests to fail. If we can find a fingerprint for a specific bug using logs, then we can use ElasticSearch to automatically detect any occurrences of the bug.

Using these fingerprints elastic-recheck can:

  • Search ElasticSearch for all occurrences of a bug.
  • Identify bug trends such as: when it started, is the bug fixed, is it getting worse, etc.
  • Classify bug failures in real time and report back to gerrit if we find a match, so a patch author knows why the test failed.

queries/

All queries are stored in separate yaml files in a queries directory at the top of the elastic-recheck code base. The format of these files is ######.yaml (where ###### is the launchpad bug number), the yaml should have a query keyword which is the query text for elastic search.

Guidelines for good queries

  • After a bug is resolved and has no more hits in elasticsearch, we should flag it with a resolved_at keyword. This will let us keep some memory of past bugs, and see if they come back.
  • Queries should get as close as possible to fingerprinting the root cause
  • Queries should not return any hits for successful jobs, this is a sign the query isn't specific enough

In order to support rapidly added queries, it's considered socially acceptable to +A changes that only add 1 new bug query, and to even self approve those changes by core reviewers.

Adding Bug Signatures

Most transient bugs seen in gate are not bugs in tempest associated with a specific tempest test failure, but rather some sort of issue further down the stack that can cause many tempest tests to fail.

  1. Given a transient bug that is seen during the gate, go through the logs (logs.openstack.org) and try to find a log that is associated with the failure. The closer to the root cause the better.
  2. Go to logstash.openstack.org and create an elastic search query to find the log message from step 1. To see the possible fields to search on click on an entry. Lucene query syntax is available at http://lucene.apache.org/core/4_0_0/queryparser/org/apache/lucene/queryparser/classic/package-summary.html#package_description
  3. Add a comment to the bug with the query you identified and a link to the logstash url for that query search.
  4. Add the query to elastic-recheck/queries/BUGNUMBER.yaml and push the patch up for review. https://git.openstack.org/cgit/openstack-infra/elastic-recheck/tree/queries

Future Work

  • Move config files into a separate directory
  • Make unit tests robust
  • Add debug mode flag
  • Expand gating testing
  • Cleanup and document code better
  • Add ability to check if any resolved bugs return
  • Move away from polling ElasticSearch to discover if its ready or not
  • Add nightly job to propose a patch to remove bug queries that return no hits -- Bug hasn't been seen in 2 weeks and must be closed