Geo: Default feature flag enabled for snippets

What

Default the :geo_snippet_repository_replication feature flag to enabled.

Owners

• Team: @geo-team
• Most appropriate slack channel to reach out to: #g_geo
• Best individual to reach out to: @mkozono

Expectations

### What are we expecting to happen?

On staging.gitlab.com, Snippets selected for sync should be replicated to geo.staging.gitlab.com.

On gitlab.com, nothing, since there is no secondary.

What might happen if this goes wrong?

Worst case is probably errors during creation of Snippets on the primary. Next might be errors in Geo-related jobs.

What can we monitor to detect problems with this?

Staging:

• https://staging.gitlab.com/admin/geo/nodes
• Sidekiq queue lengths and errors https://dashboards.gitlab.net/d/sidekiq-main/sidekiq-overview?orgId=1&var-PROMETHEUS_DS=Global&var-environment=gstg&var-stage=main&var-sigma=2

Prod:

• Sidekiq queue lengths and errors https://dashboards.gitlab.net/d/sidekiq-main/sidekiq-overview?orgId=1

Beta groups/projects

N/A

Roll Out Steps

• Enable on staging
• Test on staging
• Test on Omnibus + Geo test instances
• Ensure that documentation has been updated
• [-] Enable on GitLab.com for individual groups/projects listed above and verify behaviour
• [-] Coordinate a time to enable the flag with #production and #g_delivery on slack.
• [-] Announce on the issue an estimated time this will be enabled on GitLab.com
• [-] Enable on GitLab.com by running chatops command in #production
• [-] Cross post chatops slack command to #support_gitlab-com and in your team channel
• [-] Announce on the issue that the flag has been enabled
• Enable the feature flag by default, and add changelog entry =>
• Open the issue to make replication disableable per resource =>