[GPRD][PG14][CI] Re-Provision PG14 CI cluster

Production Change

Change Summary

Provisions a new CI cluster for postgres upgrade.

Change Details

Services Impacted - ServicePatroniCI
Change Technician - @alexander-sosna
Change Reviewer - @anganga
Time tracking - 1.5 h
Downtime Component - none

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 15 minutes

Set label changein-progress /label ~change::in-progress

Execute knife search 'roles:gprd-base-db-patroni-ci-v14' -i

  4 items found

  patroni-ci-v14-102-db-gprd.c.gitlab-production.internal
  patroni-ci-v14-101-db-gprd.c.gitlab-production.internal
  patroni-ci-v14-104-db-gprd.c.gitlab-production.internal
  patroni-ci-v14-103-db-gprd.c.gitlab-production.internal

   patroni-ci-v14-101-db-gprd.c.gitlab-production.internal:~$ sudo gitlab-patronictl list
   +--------+------+------+-------+----+-----------+
   | Member | Host | Role | State | TL | Lag in MB |
   + Cluster: gprd-patroni-ci-v14 (6959847276950353+
   +--------+------+------+-------+----+-----------+

Since this is now a rebuild destroy the machines, tf destroy -target="module.patroni-ci-v14"
Remove the nodes from Chef
- knife node delete --yes patroni-ci-v14-10{1..4}-db-gprd.c.gitlab-production.internal
- knife client delete --yes patroni-ci-v14-10{1..4}-db-gprd.c.gitlab-production.internal
Re-run last full pipeline to recreate hosts https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/pipelines
Verify the hosts are created
- ping patroni-ci-v14-101-db-gprd.c.gitlab-production.internal
- ping patroni-ci-v14-102-db-gprd.c.gitlab-production.internal
- ping patroni-ci-v14-103-db-gprd.c.gitlab-production.internal
- ping patroni-ci-v14-104-db-gprd.c.gitlab-production.internal
Confirm the silence created for patroni-ci-v14 cluster is not expired https://alerts.gitlab.net/#/silences/24ff1b19-1d16-4c09-b1e4-d38d4208a539
Follow steps to create a new replication only cluster as documented at 5.2. Stop patroni and reset WAL directory from old files
knife ssh 'roles:gprd-base-db-patroni-ci-v14' "sudo chmod 700 /var/opt/gitlab/postgresql/data12/pg_wal; sudo chown gitlab-psql:gitlab-psql /var/opt/gitlab/postgresql/data12/pg_wal"
- git clone https://gitlab.com/gitlab-com/gl-infra/db-migration.git
- cd db-migration/pg-replica-rebuild
- ansible -i inventory/patroni-ci-v14-gprd.yml all -m ping
- ansible-playbook -i inventory/patroni-ci-v14-gprd.yml rebuild-all.yml
- Run chef-client on each node of the cluster
  - knife ssh "role:gprd-base-db-patroni-ci-v14" "sudo chef-client"
- SSH into one node and check cluster status
  - ssh patroni-ci-v14-101-db-gprd.c.gitlab-production.internal
  - sudo gitlab-patronictl list
Verify the host hast started to catch up, execute on patroni-ci-v14-101 in psql: gitlabhq_production=# SELECT * FROM pg_stat_replication; and check that patroni-ci-v14-102 is replicating.
Set label changecomplete /label ~change::complete

Rollback

There is no rollback needed. If this run fails we iterate on the process and retry.

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

Estimated Time to Complete (mins)

Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

Metric: Patroni ci (GPRD)
- Location: https://dashboards.gitlab.net/goto/zdqwUrlVR?orgId=1
- What changes to this metric should prompt a rollback: * A sharp increase in the error ratio.

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.

Edited Jul 05, 2023 by Alexander Sosna