Feature flag rollout: async_mr_pipeline_creation

Summary

This issue is to roll out the async pipeline creation for new merge requests on production, that is currently behind the async_mr_pipeline_creation feature flag.

Related MR: !217381

Owners

  • Most appropriate Slack channel to reach out to: #g_code_review
  • Best individual to reach out to: @marc_shaw

Expectations

What are we expecting to happen?

When enabled, pipeline creation for new merge requests will be performed asynchronously via MergeRequests::CreatePipelineWorker instead of synchronously in NewMergeRequestWorker. This should reduce the P90 latency of NewMergeRequestWorker from over 3 seconds to under 1 second (S3 criteria target).

What can go wrong and how would we detect it?

  • Pipeline creation could fail silently or be delayed, causing merge requests to appear without pipelines longer than expected
  • Monitor NewMergeRequestWorker latency metrics and pipeline creation success rates
  • Watch for increased errors in MergeRequests::CreatePipelineWorker
  • Check for user reports of missing pipelines on newly created merge requests

Rollout Steps

Note: Please make sure to run the chatops commands in the Slack channel that gets impacted by the command.

Rollout on non-production environments

  • Verify the MR with the feature flag is merged to master and has been deployed to non-production environments with /chatops run auto_deploy status <merge-commit-of-your-feature>

  • Deploy the feature flag at a percentage (recommended percentage: 50%) with /chatops run feature set async_mr_pipeline_creation 50 --actors --dev --pre --staging --staging-ref

  • Monitor that the error rates did not increase (repeat with a different percentage as necessary).

  • Enable the feature globally on non-production environments with /chatops run feature set async_mr_pipeline_creation true --dev --pre --staging --staging-ref

  • Verify that the feature works as expected. The best environment to validate the feature in is staging-canary as this is the first environment deployed to. Make sure you are configured to use canary.

  • If the feature flag causes end-to-end tests to fail, disable the feature flag on staging to avoid blocking deployments.

Before production rollout

  • If the change is significant and you wanted to announce in #whats-happening-at-gitlab, it best to do it before rollout to gitlab-org/gitlab-com.

Specific rollout on production

For visibility, all /chatops commands that target production must be executed in the #production Slack channel and cross-posted (with the command results) to the responsible team's Slack channel.

  • Ensure that the feature MRs have been deployed to both production and canary with /chatops run auto_deploy status <merge-commit-of-your-feature>
  • For project-actor: /chatops run feature set --project=gitlab-org/gitlab,gitlab-org/gitlab-foss,gitlab-com/www-gitlab-com async_mr_pipeline_creation true
  • Verify that the feature works for the specific actors.

Preparation before global rollout

  • Set a milestone to this 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.
  • Ensure that documentation exists for the feature, and the version history text has been updated.
  • Notify the #support_gitlab-com Slack channel and your team channel.

Global rollout on production

For visibility, all /chatops commands that target production must be executed in the #production Slack channel and cross-posted (with the command results) to the responsible team's Slack channel.

  • Incrementally roll out the feature on production.
    • /chatops run feature set async_mr_pipeline_creation 10 --actors
    • /chatops run feature set async_mr_pipeline_creation 25 --actors
    • /chatops run feature set async_mr_pipeline_creation 50 --actors
    • /chatops run feature set async_mr_pipeline_creation 100 --actors
    • Between every step wait for at least 15 minutes and monitor the appropriate graphs on https://dashboards.gitlab.net.
  • After the feature has been 100% enabled, wait for at least one day before releasing the feature.

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 the async_mr_pipeline_creation feature flag. The MR should include:
    • Remove all references to the feature flag from the codebase.
    • Remove the YAML definitions for the feature from the repository.
  • Ensure that the cleanup MR has been included in the release package.
  • Once the cleanup MR has been deployed to production, clean up the feature flag from all environments: /chatops run feature delete async_mr_pipeline_creation --dev --pre --staging --staging-ref --production
  • Close this rollout issue.

Rollback Steps

  • This feature can be disabled on production by running the following Chatops command:
/chatops run feature set async_mr_pipeline_creation false
  • Disable the feature flag on non-production environments:
/chatops run feature set async_mr_pipeline_creation false --dev --pre --staging --staging-ref
  • Delete feature flag from all environments:
/chatops run feature delete async_mr_pipeline_creation --dev --pre --staging --staging-ref --production
Edited by 🤖 GitLab Bot 🤖