2023-02-07: Removing PREVENT_LOAD_BALANCER_RETRIES_IN_TRANSACTION env variable

🔴 This is dependent on the completion of gitlab-org/gitlab!109108 (merged) 🔴 - Done ✅

Production Change

Change Summary

We introduced the usage of PREVENT_LOAD_BALANCER_RETRIES_IN_TRANSACTION ENV variable in gitlab-org/gitlab!90447 (merged), it's been in production for enough period that we have decided to cleanup the ENV variable (defaulting to true).

Cleanup of the ENV usage is already done in gitlab-org/gitlab!109108 (merged)

Change Details

1. Services Impacted - ServiceWeb ServiceAPI ServiceGitLab Rails
2. Change Technician - @praba.m7n
3. Change Reviewer - DRI for the review of this change
4. Time tracking - Unknown
5. Downtime Component - N/A

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
• Merge the MR (gitlab-com/gl-infra/k8s-workloads/gitlab-com!2523 (merged)) to remove the ENV in gstg and gprd ENVs
• Set label changecomplete /label ~change::complete

Rollback

We should not be in this position since all the place where we refer to this ENV variable is already removed, so we don't have to re-introduce them.

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

• Contacting the DRI (@praba.m7n) and letting database team know about any incident by tagging (gitlab-org/database-team).
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• Metric: rails_primary_sql SLI Apdex

  • Location: https://dashboards.gitlab.net/d/patroni-main/patroni-overview?orgId=1&viewPanel=2409561530&from=now-6h&to=now
  • What changes to this metric should prompt a rollback: Any drop in apdex

• Metric: PostgreSQL Overview dashboard

  • Location: https://dashboards.gitlab.net/d/000000144/postgresql-overview?orgId=1&from=now-6h&to=now
  • What changes to this metric should prompt a rollback: Any deviation from the normal state

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.