2023-07-06: [CI Runners] divert traffic from `shared` to `small` fleet - attempt#2
Production Change
Change Summary
Previously attempted in #15990 (closed).
This CR is raised for visibility while we divert the traffic from the current infrastructure to the new one.
Change Details
- Services Impacted - ServiceCI Runners
-
Change Technician -
@rehab
- Change Reviewer - @rehab
- Time tracking - 30 minutes
- Downtime Component - none
Detailed steps for the change
Change Steps - steps to take to execute the change
Estimated Time to Complete (mins) - 30m
-
Set label changein-progress /label ~change::in-progress
-
Enable and run chef-client
andgitlab-runner
service on <50% ofsmall-blue
VMs.➜ ~ cat 50_small_hosts_blue runners-manager-saas-linux-small-amd64-blue-1.c.gitlab-ci-155816.internal runners-manager-saas-linux-small-amd64-blue-2.c.gitlab-ci-155816.internal ➜ ~ cat enable-chef-client.sh #!/bin/bash sudo su - chef-client-enable chef-client service gitlab-runner start service gitlab-runner status ➜ ~ parallel-ssh -t 0 -p 50 -o small-fleet-logs -h 50_small_hosts_blue -I <enable-chef-client.sh
-
confirm jobs are running as expected in the new cluster 👉 Kibana logs. -
Enable and run chef-client
andgitlab-runner
service on 100% ofsmall-blue
VMs.➜ ~ cat small_hosts_blue runners-manager-saas-linux-small-amd64-blue-1.c.gitlab-ci-155816.internal runners-manager-saas-linux-small-amd64-blue-2.c.gitlab-ci-155816.internal runners-manager-saas-linux-small-amd64-blue-3.c.gitlab-ci-155816.internal runners-manager-saas-linux-small-amd64-blue-4.c.gitlab-ci-155816.internal runners-manager-saas-linux-small-amd64-blue-5.c.gitlab-ci-155816.internal ➜ ~ cat enable-chef-client.sh #!/bin/bash sudo su - chef-client-enable chef-client service gitlab-runner start service gitlab-runner status ➜ ~ parallel-ssh -t 0 -p 50 -o small-fleet-logs -h small_hosts_blue -I <enable-chef-client.sh
-
Disable chef-client
andgitlab-runner
service onshared-blue
VMs.➜ ~ cat shared_hosts_blue runners-manager-shared-blue-1.c.gitlab-ci-155816.internal runners-manager-shared-blue-2.c.gitlab-ci-155816.internal runners-manager-shared-blue-3.c.gitlab-ci-155816.internal runners-manager-shared-blue-4.c.gitlab-ci-155816.internal runners-manager-shared-blue-5.c.gitlab-ci-155816.internal ➜ ~ cat disable-chef-client.sh #!/bin/bash sudo su - chef-client-disable "https://gitlab.com/gitlab-com/gl-infra/production/-/issues/15990" chef-client-is-enabled service gitlab-runner stop service gitlab-runner status ➜ ~ parallel-ssh -t 0 -p 50 -o shared-fleet-logs -h shared_hosts_blue -I <disable-chef-client.sh
-
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) - 30m
-
Disable chef-client
andgitlab-runner
service onsmall-blue
VMs.➜ ~ cat disable-chef-client.sh #!/bin/bash sudo su - chef-client-disable "https://gitlab.com/gitlab-com/gl-infra/production/-/issues/15990" chef-client-is-enabled service gitlab-runner stop service gitlab-runner status ➜ ~ parallel-ssh -t 0 -p 50 -o small-fleet-logs -h small_hosts_blue -I <disable-chef-client.sh
-
Set label changeaborted /label ~change::aborted
Monitoring
Key metrics to observe
-
Metric: Kibana logs
- Location: https://log.gprd.gitlab.net/goto/c5991d90-1b6f-11ee-8afc-c9851e4645c0
- What changes to this metric should prompt a rollback: Unexpected errors.
-
Metric: Incident Support Autoscaling
- Location: https://dashboards.gitlab.net/goto/HsFd-P94g?orgId=1
- What changes to this metric should prompt a rollback: Growing pending jobs queue, or a sharp decrease on processed jobs.
-
Metric: CI Runners Service Overview
- Location: https://dashboards.gitlab.net/goto/hDwtaP94R?orgId=1
- What changes to this metric should prompt a rollback: Increase in error ratios, or a drop in the Apdex.
-
Metric: CI Runners Deployment Overview
- Location: https://dashboards.gitlab.net/goto/og-MEy94g?orgId=1
- What changes to this metric should prompt a rollback: Increase on failures (by instance).
Change Reviewer checklist
-
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.
-
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.
Edited by Rehab