Rollout of `ci_unlock_pipelines_queue` feature flag

Production Change

Change Summary

This is for the rollout of gitlab-org/gitlab#415503 (closed).

The reason we are opening a change management issue for this is based on the documentation:

When feature toggles, or associated features, have previously had to be rolled back due to user-impacting service degradation, or as a result of the previous toggle leading to a production incident.

This new mechanism for unlocking pipelines is to prevent what happened before in #8621 (closed).

Change Details

1. Services Impacted - ServiceRedis ServiceSidekiq ServicePostgres
2. Change Technician - @iamricecake
3. Change Reviewer - DRI for the review of this change
4. Time tracking - Around 4 days to incrementally enable feature flag to all projects.
5. Downtime Component - N/A

Set Maintenance Mode in GitLab

N/A

Detailed steps for the change

Change Steps - steps to take to execute the change

At this point, we have already enabled ci_unlock_pipelines_medium for the limited capacity worker during the gitlab-only-projects test of the FF rollout. So here we will just slowly rollout ci_unlock_pipelines_queue to all projects.

Estimated Time to Complete (1 day per 25% increment, total of 4 days)

• Set label changein-progress /label ~change::in-progress
• /chatops run feature set ci_unlock_pipelines_queue 25 --actors
• /chatops run feature set ci_unlock_pipelines_queue 50 --actors
• /chatops run feature set ci_unlock_pipelines_queue 75 --actors
• /chatops run feature set ci_unlock_pipelines_queue 100 --actors
• Set label changecomplete /label ~change::complete

Rollback

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

Disable ci_unlock_pipelines_queue to prevent more pipelines to be enqueued.

Disable ci_unlock_pipelines_high|ci_unlock_pipelines_medium|ci_unlock_pipelines to prevent the limited capacity worker from picking up any more new jobs.

Estimated Time to Complete (mins) - 5 mins

• /chatops run feature set ci_unlock_pipelines_queue false
• /chatops run feature set ci_unlock_pipelines_high false
• /chatops run feature set ci_unlock_pipelines_medium false
• /chatops run feature set ci_unlock_pipelines false
• Set label changeaborted /label ~change::aborted

Monitoring

From gitlab-org/gitlab#415503 (closed)

• New Unlock Pipelines Mechanism Kibana Dashboard
• Redis Grafana Dashboard
• Grafana Ci::Refs::UnlockPreviousPipelinesWorker Overview
• Grafana Ci::UnlockPipelinesInQueueWorker Overview
• Kibana Logs for Ci::Refs::UnlockPreviousPipelinesWorker
  • Observe the following metadata attributes:
    • total_pending_entries
      • If there is a continuous increase of this number for a long time, consider increasing the limited capacity worker rate.
    • total_new_entries
• Kibana Logs for Ci::UnlockPipelinesInQueueWorker
  • Observe the following metadata attributes:
    • exec_timeout
      • This is not necessarily a bad thing, the worker is designed to pick up where it left off.
      • We can observe this in correlation with other factors to see if the workers can keep up with the amount of enqueued pipelines.
    • unlocked_job_artifacts
    • unlocked_pipeline_artifacts
• Grafana Sidekiq Overview
• Grafana PostgreSQL Overview
• Grafana PostgreSQL Tuple stat

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 change window has been agreed with Release Managers in advance of the change. If the change is planned for APAC hours, this issue has an agreed pre-change approval.
  • 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 prior to any C1, C2, or blocks deployments 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.