Rollout multiple_cache_per_job feature flag

What

Rollout of the feature flag multiple_cache_per_job

Owners

• Team: pipeline authoring
• Most appropriate slack channel to reach out to: #g_pa_engineering
• Best individual to reach out to: @lauraMon

Related to: !53410 (merged), #32814 (closed)

Beta groups/projects

• multiple-cache personal project
• gitlab-org/gitlab project
• gitlab-org/gitlab-com groups

Roll Out Steps

• Enable on beta groups/projects
• Enable on staging (/chatops run feature set feature_name true --staging)
• Test on staging
• Ensure that documentation has been updated
• Enable on GitLab.com for individual groups/projects listed above and verify behaviour (/chatops run feature set --project=gitlab-org/gitlab feature_name true)
• Coordinate a time to enable the flag with the SRE oncall and release managers
  • In #production mention @sre-oncall and @release-managers. Once an SRE on call and Release Manager on call confirm, you can proceed with the rollout
• Announce on the issue an estimated time this will be enabled on GitLab.com
• Enable on GitLab.com by running chatops command in #production (/chatops run feature set feature_name 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
• Remove feature flag and add changelog entry. Ensure that the feature flag definition YAML file has been removed in the same MR that is removing the feature flag from the code
• After the flag removal is deployed, clean up the feature flag by running chatops command in #production channel

Additional cleanup

• Remove the strategy from Entry::Cache and separate into Entry::Cache and Entry::Caches. This will require changing Entry::Cache in Entry::Job, Entry::Root and Entry::Default to always make cache go through Caches.
• Cleanup the specs, which have cases for both. #323544 (closed) #322740 (closed) #323543 (closed)

Rollback Steps

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

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