[Feature Flag] Rollout of `ci_remove_ensure_stage_service`

Summary

This issue is to rollout the feature on production, that is currently behind the ci_remove_ensure_stage_service feature flag.

❗ When deleting this FF, please search for all ci_remove_ensure_stage_service related comments ❗

Owners

• Team: grouppipeline authoring
• Most appropriate slack channel to reach out to: #g_pipeline_authoring
• Best individual to reach out to: @lauraX

Expectations

What are we expecting to happen?

We expect that all builds will have a stage, and not need the EnsureStageService anymore.

Rollout Steps

Rollout on non-production environments

• Verify the MR with the feature flag is merged to master.
• Verify that the feature MRs have been deployed to non-production environments with:
  • /chatops run auto_deploy status <merge-commit-of-your-feature>
• Enable the feature globally on non-production environments.
  • /chatops run feature set ci_remove_ensure_stage_service true --dev --staging --staging-ref
• Verify that the feature works as expected. Posting the QA result in this issue is preferable. The best environment to validate the feature in is staging-canary as this is the first environment deployed to. Note you will need to make sure you are configured to use canary as outlined here when accessing the staging environment in order to make sure you are testing appropriately.

Specific rollout on production

• Ensure that the feature MRs have been deployed to both production and canary.
  • /chatops run auto_deploy status <merge-commit-of-your-feature>
• Depending on the type of actor you are using, pick one of these options:
  • If you're using project-actor, you must enable the feature on these entries:
    • /chatops run feature set --project=gitlab-org/gitlab,gitlab-org/gitlab-foss,gitlab-com/www-gitlab-com ci_remove_ensure_stage_service true
• Verify that the feature works on the specific entries. Posting the QA result in this issue is preferable.

Preparation before global rollout

• Set a milestone to the rollout issue to signal for enabling and removing the feature flag when it is stable.
• [-] Check if the feature flag change needs to be accompanied with a change management issue. Cross link the issue here if it does.
• Ensure that you or a representative in development can be available for at least 2 hours after feature flag updates in production. If a different developer will be covering, or an exception is needed, please inform the oncall SRE by using the @sre-oncall Slack alias.
• [-] Ensure that documentation has been updated (More info).
• [-] Leave a comment on [the feature issue][main-issue] announcing estimated time when this feature flag will be enabled on GitLab.com.
• [-] Ensure that any breaking changes have been announced following the release post process to ensure GitLab customers are aware.
• Notify #support_gitlab-com and your team channel (more guidance when this is necessary in the dev docs).

Global rollout on production

• Incrementally roll out the feature.
  • /chatops run feature set ci_remove_ensure_stage_service 25 --actors
  • /chatops run feature set ci_remove_ensure_stage_service 50 --actors
  • /chatops run feature set ci_remove_ensure_stage_service 75 --actors
  • /chatops run feature set ci_remove_ensure_stage_service 100 --actors
• Between every step wait for at least 15 minutes and monitor the appropriate graphs on https://dashboards.gitlab.net.
  • Enable the feature globally on production environment.
    • /chatops run feature set ci_remove_ensure_stage_service true
• Observe appropriate graphs on https://dashboards.gitlab.net and verify that services are not affected.
• Leave a comment on [the feature issue][main-issue] announcing that the feature has been globally enabled.
• Wait for at least one day for the verification term.

Release the feature

Before this is enabled by default, we must make sure that ci_builds.stage_id is backfilled for self-managed.

You can either create a follow-up issue for Feature Flag Cleanup or use the checklist below in this same issue.

• Create a merge request to remove <feature-flag-name> feature flag. Ask for review and merge it.
  • Remove all references to the feature flag from the codebase.
  • Remove the YAML definitions for the feature from the repository.
  • Create a changelog entry.
• Ensure that the cleanup MR has been deployed to both production and canary. If the merge request was deployed before the code cutoff, the feature can be officially announced in a release blog post.
  • /chatops run auto_deploy status <merge-commit-of-cleanup-mr>
• Close the feature issue to indicate the feature will be released in the current milestone.
• Clean up the feature flag from all environments by running these chatops command in #production channel:
  • /chatops run feature delete ci_remove_ensure_stage_service --dev
  • /chatops run feature delete ci_remove_ensure_stage_service --staging
  • /chatops run feature delete ci_remove_ensure_stage_service

Rollback Steps

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

/chatops run feature set ci_remove_ensure_stage_service false