[GPRD] Create patroni-main-logical-pg13 for testing logical replication in gprd

Production Change

Change Summary

This will create the new database cluster patroni-main-logical-pg13, which replicates from the patroni-main cluster and starts off as a standby only cluster. This cluster will be used by the DBRE to test the impact of logical replication in gprd.

Scheduled: 11 AM UTC on the 12 of January 2023.

Change Details

1. Services Impacted - ServicePostgres Database
2. Change Technician - @Finotto @alexander-sosna
3. Change Reviewer - @Finotto @alexander-sosna
4. Time tracking - 1 hour
5. Downtime Component - None*.

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
• Check if the last snapshot is not too old, with gcloud compute snapshots list --project gitlab-production --sort-by=~creationTimestamp --filter='sourceDisk~patroni-ci-2004-* AND description~gcs-snapshot' --format "value(creationTimestamp,name)" --limit 1
  • Create fresh snapshot if necessary, with snapshots create
• Merge https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4785
• Let the automatic CI job create the cluster
• 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

• Revert https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4785
• Let the automatic CI job de-provision the cluster
  • If automation fails de-provision manually by terraform apply
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• Metric: Node Stats
  • Location: https://dashboards.gitlab.net/d/bd2Kl9Imk/host-stats?orgId=1 for the new node.
  • What changes to this metric should prompt a rollback: Evaluate the metrics of the new node. In case of high CPU utilization or context switches over 500k, please rollback.

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.