[Feature flag] [Geo] Enable MR diffs verification feature

Feature

This feature uses the :geo_merge_request_diff_verification feature flag!

• Geo: Self Service Framework - Verify Merge request Diffs

Owners

• Team: groupgeo
• Most appropriate slack channel to reach out to: #g_geo
• Best individual to reach out to: @aakriti.gupta
• PM: @fzimmer

Stakeholders

The Rollout Plan

• Rollout Feature for everyone as soon as it's ready

Expectations

What are we expecting to happen?

Nothing is expected to change on GitLab.com since Geo is not used on the site.

On staging, we expect verification to work for new and old MR diffs.

What might happen if this goes wrong?

• Turn off the feature flag
• If (unlikely) that is not enough !60935 (merged) can be rolled back
• On staging, some MR diffs will not be verified, but that is not a regression.

What can we monitor to detect problems with this?

• Check Sentry errors on staging

Rollout Timeline

Rollout Steps

Preparation Phase

• Enable on staging (/chatops run feature set feature_name true --staging)

• Test on staging

• 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

• Announce on the issue an estimated time this will be enabled on GitLab.com

• 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

Rollback Steps

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

/chatops run feature set --project=gitlab-org/gitlab geo_merge_request_diff_verification false