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[Feature flag] Enable FF: `method_instrumentation_disable_initialization`

Summary

This issue is to rollout the disable of method instrumentation initialization during the app startup, which is the part of #217978 (closed) on production, that is currently behind the method_instrumentation_disable_initialization feature flag.

Owners

  • Team: Memory
  • Most appropriate slack channel to reach out to: #g_memory
  • Best individual to reach out to: @alipniagov
  • PM: @fzimmer

The Rollout Plan

  • Rollout on staging, check that the app restarted after that without any issue
  • Rollout on GitLab.com under observation during the period long enough, so that the restart(s) of the app would happen.
  • If all is fine, keep it enabled

Expectations

What are we expecting to happen?

What might happen if this goes wrong?

We will no longer collect metrics on methods execution time: #217978 (comment 660073732)

We expect these metrics are no longer used and I grepped the runbooks, but if they were somehow used somewhere implicitly, they would disappear.

What can we monitor to detect problems with this?

We shouldn't receive any new related alearts.
We need to make sure the application starts well.

Rollout Steps

Rollout on non-production environments

  • Ensure that the feature MRs have been deployed to non-production environments.
    • /chatops run auto_deploy status 106e63e81053ae2106cd4fcd49236e45635fed28
  • Enable the feature globally on non-production environments.
    • /chatops run feature set method_instrumentation_disable_initialization true --dev
    • /chatops run feature set method_instrumentation_disable_initialization true --staging
  • Verify that the feature works as expected. Posting the QA result in this issue is preferable.

Preparation before production rollout

  • Ensure that the feature MRs have been deployed to both production and canary.
    • /chatops run auto_deploy status <merge-commit-of-your-feature>
  • 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).
  • Announce on the feature issue an estimated time this will be enabled on GitLab.com.
  • If the feature might impact the user experience, notify #support_gitlab-com and your team channel (more guidance when this is necessary in the dev docs).

Global rollout on production

All /chatops commands that target production should be done in the #production slack channel for visibility.

No partial rollout in this case - as it wouldn't make change with initializer change.

  • Confirm the feature flag is enabled on staging without incident
  • Enable the feature globally on production environment. /chatops run feature set method_instrumentation_disable_initialization true
  • Announce on the feature issue that the feature has been globally enabled.
  • Wait for at least one day for the verification term.

(Optional) Release the feature with the feature flag

N/A

Release the feature

After the feature has been deemed stable, the clean up should be done as soon as possible to permanently enable the feature and reduce complexity in the codebase.

  • Create a merge request to remove method_instrumentation_disable_initialization 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 649f624f034063c770a4200bb857316e5789dc99
  • 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 method_instrumentation_disable_initialization --dev
    • /chatops run feature delete method_instrumentation_disable_initialization --staging
    • /chatops run feature delete method_instrumentation_disable_initialization
  • Close this rollout issue.

Rollback Steps

  • This feature can be disabled by running the following Chatops command:
/chatops run feature set method_instrumentation_disable_initialization false
Edited by Aleksei Lipniagov