Enable Index Lifecycle Management for Advanced Search Indices

Production Change

Change Summary

This will add index lifecycle management to Advance Search indices by rolling over indices that exceed our sizing guidance.

Per-index ops feature flags:

• search_index_curation_main_index
• search_index_curation_users
• search_index_curation_notes
• search_index_curation_merge_requests
• search_index_curation_issues
• search_index_curation_commits

Change Details

1. Services Impacted - Elasticsearch -- global search
2. Change Technician - @john-mason
3. Change Reviewer - @dgruzd
4. Time tracking - 2h
5. Downtime Component - 6h

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - Estimated Time to Complete in Minutes

• Set label changein-progress /label ~change::in-progress
• See which indices would be rolled over. Note the output in a comment on this issue. ::Gitlab::Search::IndexCurator.new(dry_run: true, max_docs_denominator: Gitlab::CurrentSettings.search_max_docs_denominator, min_docs_before_rollover: Gitlab::CurrentSettings.search_min_docs_before_rollover).todo
• Pick the smallest in gb of indices from the output that would be rolled over. The index is gitlab-production-users-20221109-1240-reindex-4-0
• Ensure search_curation_dry_run is enabled for curation worker: /chatops run feature set search_curation_dry_run true
• Enable search curation worker /chatops run feature set search_index_curation true
• Enable the ops feature flag for gitlab-production-users-20221109-1240-reindex-4-0
• Ensure there is a log entry 30 minutes later for gitlab-production-users-20221109-1240-reindex-4-0 being rolled over
• Disable search_curation_dry_run for curation worker: /chatops run feature set search_curation_dry_run false
• Ensure there is a log entry 30 minutes later for gitlab-production-users-20221109-1240-reindex-4-0 being rolled over
• Ensure gitlab-production-users-20221109-1240-reindex-4-0 has been properly rolled over 30 minutes later.
• Save content that will be indexed in newly rolled over index for gitlab-production-users-20221109-1240-reindex-4-0 and ensure content is searchable
• Enable ops feature flags for remaining indices, leaving main_index for last.
• Set label changecomplete /label ~change::complete

Rollback

Rollback steps - steps to be taken in the event of a need to rollback this change

Estimated Time to Complete (mins) - Estimated Time to Complete in Minutes

• Pause indexing
• Use reindexing API to combine split indices into one
• Change the alias to point to the reindexed one
• Unpause indexing
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• Metric: GET /_cat/indices/gitlab-production*?v

  • Location: Kibana for relevant cluster

• Metric: ElasticSearch queue size

  • Location: https://dashboards.gitlab.net/d/stage-groups-global_search/stage-groups-global-search-group-dashboard?orgId=1
  • What changes to this metric should prompt a rollback: If the queue size is consistently getting larger it is an indication of indexing failing.

Change Reviewer checklist

C4 C3 C2 C1:

• Check if the following applies:
  • The scheduled day and time of execution of the change is appropriate.
  • The change plan is technically accurate.
  • The change plan includes estimated timing values based on previous testing.
  • The change plan includes a viable rollback plan.
  • The specified metrics/monitoring dashboards provide sufficient visibility for the change.

C2 C1:

• Check if the following applies:
  • The complexity of the plan is appropriate for the corresponding risk of the change. (i.e. the plan contains clear details).
  • The change plan includes success measures for all steps/milestones during the execution.
  • The change adequately minimizes risk within the environment/service.
  • The performance implications of executing the change are well-understood and documented.
  • The specified metrics/monitoring dashboards provide sufficient visibility for the change.
    • If not, is it possible (or necessary) to make changes to observability platforms for added visibility?
  • The change has a primary and secondary SRE with knowledge of the details available during the change window.
  • The labels blocks deployments and/or blocks feature-flags are applied as necessary

Change Technician checklist

• Check if all items below are complete:
  • The change plan is technically accurate.
  • This Change Issue is linked to the appropriate Issue and/or Epic
  • Change has been tested in staging and results noted in a comment on this issue.
  • A dry-run has been conducted and results noted in a comment on this issue.
  • The change execution window respects the Production Change Lock periods.
  • For C1 and C2 change issues, the change event is added to the GitLab Production calendar.
  • For C1 and C2 change issues, the SRE on-call has been informed prior to change being rolled out. (In #production channel, mention @sre-oncall and this issue and await their acknowledgement.)
  • For C1 and C2 change issues, the SRE on-call provided approval with the eoc_approved label on the issue.
  • For C1 and C2 change issues, the Infrastructure Manager provided approval with the manager_approved label on the issue.
  • Release managers have been informed (If needed! Cases include DB change) prior to change being rolled out. (In #production channel, mention @release-managers and this issue and await their acknowledgment.)
  • There are currently no active incidents that are severity1 or severity2
  • If the change involves doing maintenance on a database host, an appropriate silence targeting the host(s) should be added for the duration of the change.