2022-03-18: Upgrade Prometheus servers in gprd GKE Clusters

Production Change

Change Summary

Upgrade Prometheus from v2.30.0 to v2.34.0 on gprd GKE clusters

Change Details

1. Services Impacted - ServicePrometheus
2. Change Technician - @steveazz
3. Change Reviewer - @rehab
4. Time tracking - 60 minutes
5. Downtime Component - none

Detailed steps for the change

Pre-Change Steps - steps to be completed before execution of the change

Estimated Time to Complete (mins) - 1

• Make sure gitlab-com/gl-infra/k8s-workloads/gitlab-helmfiles!649 (merged) is approved.
• Set label changein-progress on this issue

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 2

• Merge gitlab-com/gl-infra/k8s-workloads/gitlab-helmfiles!649 (merged)

Post-Change Steps - steps to take to verify the change

Estimated Time to Complete (mins) - 25

• Check that gprd-us-east1-b cluster was updated and both pods are running

  # Window 1
  $ glsh kube use-cluster gprd-us-east1-b
  # Window 2
  $ watch kubectl -n monitoring get po -l app=prometheus -o wide
  # Window 3
  $ kubectl -n monitoring logs prometheus-gitlab-monitoring-promethe-prometheus-1 --follow

• Check that gprd-us-east1-c cluster was updated and both pods are running

  # Window 1
  $ glsh kube use-cluster gprd-us-east1-c
  # Window 2
  $ watch kubectl -n monitoring get po -l app=prometheus -o wide
  # Window 3
  $ kubectl -n monitoring logs prometheus-gitlab-monitoring-promethe-prometheus-1 --follow

• Check that gprd-us-east1-d cluster was updated and both pods are running

  # Window 1
  $ glsh kube use-cluster gprd-us-east1-d
  # Window 2
  $ watch kubectl -n monitoring get po -l app=prometheus -o wide
  # Window 3
  $ kubectl -n monitoring logs prometheus-gitlab-monitoring-promethe-prometheus-1 --follow

Rollback

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

Estimated Time to Complete (mins) - 30

• Revert gitlab-com/gl-infra/k8s-workloads/gitlab-helmfiles!649 (merged)

Monitoring

Key metrics to observe

• Metric: Apdex
  • Location: https://dashboards.gitlab.net/d/monitoring-main/monitoring-overview?orgId=1&viewPanel=4146537329&from=1647569940000&to=1647591599999
  • What changes to this metric should prompt a rollback: Drop in apdex
• Metric: Memory usage
  • Location: https://dashboards.gitlab.net/d/monitoring-main/monitoring-overview?orgId=1&viewPanel=4146537329&from=1647569940000&to=1647591599999
  • What changes to this metric should prompt a rollback: Memory exceeding 200Gb
• Metrics: Pod Info
  • Location: https://dashboards.gitlab.net/d/kubernetes-pods/kubernetes-pods?orgId=1&var-datasource=default&var-cluster=gprd-gitlab-gke&var-namespace=monitoring&var-pod=prometheus-gitlab-monitoring-promethe-prometheus-0&var-container=prometheus
  • What changes to this metric should prompt a rollback:
    • High CPU usage
    • Total Restarts Per Container is high

Summary of infrastructure changes

• Does this change introduce new compute instances?
• Does this change re-size any existing compute instances?
• Does this change introduce any additional usage of tooling like Elastic Search, CDNs, Cloudflare, etc?

Change Reviewer checklist

C4 C3 C2 C1:

• 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:

• 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.

Change Technician checklist

• This issue has a criticality label (e.g. C1, C2, C3, C4) and a change-type label (e.g. changeunscheduled, changescheduled) based on the Change Management Criticalities.
• This issue has the change technician as the assignee.
• Pre-Change, Change, Post-Change, and Rollback steps and have been filled out and reviewed.
• This Change Issue is linked to the appropriate Issue and/or Epic
• Necessary approvals have been completed based on the Change Management Workflow.
• 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.
• 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.)
• 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.