[GPRD] Container Registry: Enable DB load balancing

Production Change

Change Summary

This is a change request to enable the new container registry database load balancing feature (Container Registry: Database Load Balancing (DLB) (gitlab-org&8591 - closed)) in production, starting with the canary stage. This was enabled and tested in staging a while ago, as part of gitlab-org/container-registry#1379 (closed).

This change already went through the production readiness review process (https://gitlab.com/gitlab-com/gl-infra/readiness/-/issues/1210), and we're now ready to enable it.

We'd like to get it enabled during the week of January 6 to 10, preferably between 9AM and 5PM UTC (for development coverage purposes).

Change Details

  1. Services Impacted - ServiceContainer Registry
  2. Change Technician - DRI for the execution of this change
  3. Change Reviewer - @skarbek
  4. Time tracking - 30 minutes
  5. Scheduled Date and Time - Date and time planned to execute change steps
  6. Downtime Component - N/A

Set Maintenance Mode in GitLab

If your change involves scheduled maintenance, add a step to set and unset maintenance mode per our runbooks. This will make sure SLA calculations adjust for the maintenance period.

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 15 minutes

Rollback

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

Estimated Time to Complete (mins) - 15 minutes

Monitoring

Key metrics to observe

  • Metric: Registry API Apdex and Error Ratio

    • Location: https://dashboards.gitlab.net/d/registry-main/registry3a-overview
    • What changes to this metric should prompt a rollback: Even if the feature does not work as expected (e.g., the service can't connect to Consul or one of the replicas), it should cause not harm to the apdex and error ratio. In other words, it should have no customer impact, as the registry falls back to communicate with the primary database only. However, if for any unforeseen reason these get impacted, we should start a rollback immediately.

  • Metric: Load balancing specific metrics

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. Mention @gitlab-org/saas-platforms/inframanagers in this issue to request approval and provide visibility to all infrastructure managers.
    • 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.
Edited by John Skarbek