[Feature flag] Rollout of `geo_pages_deployment_replication`

Summary

This issue is to rollout the feature Geo:Replicate Pages Deployments on production, that is currently behind the geo_pages_deployment_replication feature flag.

Owners

• Team: groupgeo
• Most appropriate slack channel to reach out to: #g_geo
• Best individual to reach out to: @nhxnguyen
• PM: @nhxnguyen

Stakeholders

The Rollout Plan

• Rollout the feature for all self-managed Geo customers after successful testing on staging and a 3k Geo deployment.

Testing Groups/Projects/Users

• gitlab-org/gitlab project
• gitlab-org/gitlab-com groups
• ...

Expectations

What are we expecting to happen?

• There will be no changes for SaaS customers as Geo is not yet enabled on .com.
• Self-managed Geo customers with GitLab Pages deployments stored locally or on object storage with Geo-managed object storage replication enabled will see their Pages deployments replicated.

What might happen if this goes wrong?

• Administrators can disable the feature by toggling the feature flag.
• If disabling via feature flag is insufficient, reverting !68662 (merged) is an option.

What can we monitor to detect problems with this?

• Check sentry errors on staging.

Rollout Steps

Rollout Steps

Preparation Phase

• Enable on staging (/chatops run feature set geo_pages_deployment_replication true --staging)
• Test on staging.
• Test on a 3k-3k GET deployment.
  • Pages Deployments are replicated to the secondary.
  • Test pages functionality on a secondary without access control.
  • Test pages functionality on a secondary with access control. See #9336
• Ensure that documentation has been updated (More info)
  • Update https://gitlab.com/gitlab-org/gitlab/blob/master/doc/administration/geo/replication/datatypes.md#enable-or-disable-replication-for-some-data-types
  • Update https://gitlab.com/gitlab-org/gitlab/blob/master/doc/administration/geo/replication/datatypes.md#data-types
• Check if the feature flag change needs to be accompanied with a change management issue. Cross link the issue here if it does.

Full Rollout Phase

• Make the feature flag enabled by default i.e. Change default_enabled to true
• Cross post chatops slack command to #support_gitlab-com (more guidance when this is necessary in the dev docs) and in your team channel
• Announce on the issue that the flag has been enabled
• [-] Create a cleanup issue using the "Feature Flag Removal" template => See #325843

Rollback Steps

• This feature can be disabled by running the following Chatops command:

/chatops run feature set geo_pages_deployment_replication false