[CR][GPRD] Provision redis-cluster-shared-state

Production Change

Change Summary

To provision a new Redis Cluster for SharedState (redis-cluster-shared-state). The new cluster will host exclusive lease keys migrated from the current Redis persistent. &1094 (closed)

Change Details

1. Services Impacted - ServiceRedisClusterSharedState
2. Change Technician - @marcogreg @gsgl
3. Change Reviewer - @gsgl
4. Time tracking - 90 minutes
5. Downtime Component - NA

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) - 60 minutes

• Set label changein-progress /label ~change::in-progress
• Detailed in the comment below #16350 (comment 1554353146)
• 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) - 30 minutes

Only the 2 steps below in configuring the applications could be harmful to GitLab.com:

• Revert MR for Configure Rails in k8s-workloads - gitlab-com/gl-infra/k8s-workloads/gitlab-com!2943 (merged)
• Revert MR for Update roles/gstg-base.json for console connection - https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/3840
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• redis_connected_clients when initialising the cluster (there should be some connections to each other) and when connecting it to the pods (there should be an uptick and more pings received). https://thanos.gitlab.net/graph?g0.expr=redis_connected_clients%7Benv%3D%22gstg%22%2C%20type%3D%22redis-cluster-shared-state%22%7D&g0.tab=0&g0.stacked=0&g0.range_input=1h&g0.max_source_resolution=0s&g0.deduplicate=1&g0.partial_response=0&g0.store_matches=%5B%5D
• Metric: web service apdex & error ratio
  • Location: https://dashboards.gitlab.net/d/web-main/web-overview?orgId=1
  • What changes to this metric should prompt a rollback: apdex drop / higher error

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.