[Feature flag] Clean up `create_deployment_in_separate_transaction`

Summary

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

Owners

• Team: ~"group::release"
• Most appropriate slack channel to reach out to: #s_release
• Best individual to reach out to: @shinya.maeda
• PM: @cbalane

Stakeholders

Expectations

What are we expecting to happen?

Deployment records that are associated to pipeline jobs will be created outside of the transaction of pipeline jobs. This fixes the cross-database transaction issue.

What might happen if this goes wrong?

Since the data integrity can't be assured by separate transactions. There is a risk that a pipeline job is running without deployment association.

The other possibilities would be:

• Pipelines can't be created successfully.
• A job can't be retried successfully.

What can we check for monitoring production after rollouts?

• Sentry on DeploymentCreationError
• Sentry on CreatePipelineService
• Sentry on RetryBuildService
• Sentry on Deployment
• Kibana on DeploymentCreationError in Sidekiq
• Kibana on DeploymentCreationError in Puma
• GitLab Issue Tracker
• CrossDatabaseModificationAcrossUnsupportedTablesError

Rollout Steps

Rollout on non-production environments

• Ensure that the feature MRs have been deployed to non-production environments.
  • /chatops run auto_deploy status dc0c08601304866aadd33562cff14d41a5a0ae12
• Enable the feature globally on non-production environments.
  • /chatops run feature set create_deployment_in_separate_transaction true --dev
  • /chatops run feature set create_deployment_in_separate_transaction true --staging
• Verify that the feature works as expected. Posting the QA result in this issue is preferable.

Specific rollout on production

• Ensure that the feature MRs have been deployed to both production and canary.
  • /chatops run auto_deploy status dc0c08601304866aadd33562cff14d41a5a0ae12
• If you're using project-actor, you must enable the feature on these entries:
  • /chatops run feature set --project=gitlab-org/gitlab-foss create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/omnibus-gitlab create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/gitlab-runner create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/gitlab create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/gitlab-docs create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/gitaly create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/charts/gitlab create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/gitlab-services/design.gitlab.com create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-org/gitlab-ui", create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-com/www-gitlab-com create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-com/gitlab-com-infrastructure create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-com/gl-infra/k8s-workloads/gitlab-helmfiles create_deployment_in_separate_transaction true
  • /chatops run feature set --project=gitlab-com/business-technology/enterprise-apps/integrations/platypus create_deployment_in_separate_transaction true
• If you're using group-actor, you must enable the feature on these entries:
  • /chatops run feature set --group=gitlab-org create_deployment_in_separate_transaction true
  • /chatops run feature set --group=gitlab-com create_deployment_in_separate_transaction true
• If you're using user-actor, you must enable the feature on these entries:
  • /chatops run feature set --user=<your-username> create_deployment_in_separate_transaction true
• Verify that the feature works on the specific entries. Posting the QA result in this issue is preferable.

Preparation before global rollout

• 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.
• Notify #support_gitlab-com and your team channel (more guidance when this is necessary in the dev docs).

Global rollout on production

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

• Incrementally roll out the feature.
  • If the feature flag in code has an actor, perform actor-based rollout.
    • /chatops run feature set create_deployment_in_separate_transaction 25 --actors
    • /chatops run feature set create_deployment_in_separate_transaction 50 --actors
    • /chatops run feature set create_deployment_in_separate_transaction 75 --actors
  • If the feature flag in code does NOT have an actor, perform time-based rollout (random rollout).
    • /chatops run feature set create_deployment_in_separate_transaction <rollout-percentage>
  • Enable the feature globally on production environment.
    • /chatops run feature set create_deployment_in_separate_transaction 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

If you're still unsure whether the feature is deemed stable but want to release it in the current milestone, you can change the default state of the feature flag to be enabled. To do so, follow these steps:

• Create a merge request with the following changes. Ask for review and merge it.
  • Set the default_enabled attribute in the feature flag definition to true.
  • Create a changelog entry.
• Ensure that the default-enabling 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-default-enabling-mr>
• Close the feature issue to indicate the feature will be released in the current milestone.
• Set the next milestone to this rollout issue for scheduling the flag removal.
• (Optional) You can create a separate issue for scheduling the steps below to Release the feature.
  • Set the title to "[Feature flag] Cleanup create_deployment_in_separate_transaction".
  • Execute the /copy_metadata <this-rollout-issue-link> quick action to copy the labels from this rollout issue.
  • Link this rollout issue as a related issue.
  • Close this rollout issue.

WARNING: This approach has the downside that it makes it difficult for us to clean up the flag. For example, on-premise users could disable the feature on their GitLab instance. But when you remove the flag at some point, they suddenly see the feature as enabled and they can't roll it back to the previous behavior. To avoid this potential breaking change, use this approach only for urgent matters.

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 create_deployment_in_separate_transaction 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 819ac4ba3de026962b068f8cdff37febd46b06a8
• 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 create_deployment_in_separate_transaction --dev
  • /chatops run feature delete create_deployment_in_separate_transaction --staging
  • /chatops run feature delete create_deployment_in_separate_transaction
• Close this rollout issue.

Rollback Steps

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

/chatops run feature set create_deployment_in_separate_transaction false