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Rollout logical replication in staging

Production Change

Change Summary

The goal of this change is to enable logical replication on staging, evaluate the performance impacts and how robust the process is. We will execute the procedure described in the action steps and leave it for 72 hours.

Change Details

  1. Services Impacted - Database
  2. Change Technician - @vitabaks
  3. Change Reviewer - @Finotto / @alexander-sosna
  4. Time tracking - 2 hours
  5. Downtime Component - 0

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - Estimated Time to Complete in Minutes

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 15 min

  • Set label changein-progress /label ~change::in-progress
  • Get the Ansible Playbook physical_to_logical.yml by cloning the repository git clone git@gitlab.com:gitlab-com/gl-infra/db-migration.git FIX REPOS ON BOTH INSTANCES TO MATCH
  • Go to the folder cd db-migration/physical-to-logical
  • Set the Ansible configuration needed ANSIBLE_CONFIG=PATH_TO_CONFIG_FILE SET PATH
  • Test connectivity and add the ssh hosts as known for trust on first use ansible -i inventory/gstg.yml all -m ping
  • Change the pg_source_replica_pass variable (main cluster gitlab-superuser) in the playbook needs to be replaced by .pgpass
  • verify the hosts in inventory file.
  • Turn off the chef-client on the Standby Cluster nodes before starting the playbook: /usr/local/bin/chef-client-disable
  • Run Ansible playbook: ansible-playbook -i inventory/gstg.yml physical_to_logical.yml
  • 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) - 3 min

  • Remove subscription on the target (Standby Cluster leader): sudo gitlab-psql -c "DROP SUBSCRIPTION logical_subscription"
  • Remove publication on the source (Main Cluster leader): sudo gitlab-psql -c "DROP PUBLICATION logical_replication", and replication slot (if exists) sudo gitlab-psql -c "SELECT pg_drop_replication_slot('logical_replication_slot') from pg_replication_slots where slot_name = 'logical_replication_slot'"
  • Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

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.ff
Edited by Alexander Sosna