2023-03-01: [blue shared runners 1,2] enable Network Per-Build feature flag

Production Change

Change Summary

Simply enables the feature flag Network Per-Build for 40% of the active shared runner managers.

Reference: Rollout Network Per-Build for Linux shared runners (&905).

Change Details

1. Services Impacted - ServiceCI Runners
2. Change Technician - @rehab
3. Change Reviewer - @steveazz
4. Time tracking - 15 minutes
5. Downtime Component - none

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 5m

• Set label changein-progress /label ~change::in-progress
• Merge: https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/2943
• Apply by running chef-client on both hosts.
• Verify the change is successful

ssh runners-manager-shared-blue-[1,2].c.gitlab-ci-155816.internal
sudo ls -lrt /root/.docker/machine/machines | head
sudo -H docker-machine ssh runner-qvbvroxm-private-1677071904-c0496b72
docker network ls

# results should include a bridge similar to:
# a21752a8db68        runner-qvbvroxm-project-xxxxx-concurrent-0-job-3814347006-network   bridge              local

• 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 MR https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/2943
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• metric:

  • Location: Thanos query.

  • What changes to this metric should prompt a rollback: Sharp decrease in gitlab_runner_jobs_total.

  • Location: Thanos query.

  • What changes to this metric should prompt a rollback: Increase in gitlab_runner_failed_jobs_total.

• Dashboard: ci-runners:Overview

  • Location: https://dashboards.gitlab.net/goto/m1SyV9oVz?orgId=1
  • What changes to this metric should prompt a rollback: Sharp increase in error rates or lack of traffic.

• Dashboard: ci-runners: Incident Support: database

  • Location: https://dashboards.gitlab.net/goto/m0n84roVz?orgId=1
  • What changes to this metric should prompt a rollback:
    • Increase in pending jobs
    • Decrease in started jobs

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.