2022-10-05: Cleanup Patroni 1604 Clusters and DR Replicas on GSTG environment.

Production Change

Change Summary

Provide a high-level summary of the change and its purpose.

Change Details

1. Services Impacted - ServicePatroni ServicePatroniCI
2. Change Technician - @Shimran George
3. Change Reviewer - @mchacon3
4. Time tracking - unknown
5. Downtime Component - none

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 20 minutes

• Set label changein-progress `/label changein-progress
• Stop Patroni services on all 1604 nodes ssh_cluster_regex.sh "(patroni-0).*-db-gstg.c.gitlab-staging-1.internal" "sudo systemctl stop patroni" and (patroni-ci-0).*-db-gstg.c.gitlab-staging-1.internal" "sudo systemctl stop patroni" `
• Stop chef client on all 1604 nodes ssh_cluster_regex.sh "(patroni-0).*-db-gstg.c.gitlab-staging-1.internal" "sudosystemctl stop chef-client" and (patroni-ci-0).*-db-gstg.c.gitlab-staging-1.internal" "sudo systemctl stop chef-client"
• Merge https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/2355 to remove chef roles.
• Review https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4285
• Power down main/ci nodes in GCP console (https://console.cloud.google.com/compute/instances?project=gitlab-staging-1) with 'Stop' VM instances for main/ci nodes.
• Verify terraform plan in env gstg terraform plan or alternatively, read the 'terraform plan' stage output in CI/CD
• Merge https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4285
• Run terraform apply via CI/CD (Once MR is merged, go to stage terraform apply and manually approve stage to run)
• Verify nodes are removed in GCP console, and in chef (via knife node list)
• 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) - 20 minutes

• Revert MR: https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4285/
• Merge above MR, and rerun the terraform apply CI/CD job.
• Revert MR: https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/4285
• Re-enable chef ssh_cluster_regex.sh "(patroni-0).*-db-gstg.c.gitlab-staging-1.internal" "sudo systemctl start chef-client"`
• Re-enable patroni ssh_cluster_regex.sh "(patroni-0).*-db-gstg.c.gitlab-staging-1.internal" "sudo systemctl start patroni"`
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• Metric: Metric Name
  • Location: Dashboard URL
  • What changes to this metric should prompt a rollback: Describe Changes

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.