[Feature flag] Rollout of `gitlab_error_tracking`

Summary

This issue is to rollout the new Error Tracking feature on production, that is currently behind the gitlab_error_tracking feature flag.

Owners

• Team: Observability
• Most appropriate slack channel to reach out to: #g_observability
• Best individual to reach out to: @brodock
• PM: @sebastienpahl

Stakeholders

Expectations

What are we expecting to happen?

• Makes the "GitLab Error Tracking" section available in Admin > Settings > General

That section allows you to configure and enable Opscode based error tracking.

What are the settings we need to configure in order to have this feature viable?

1. Set the Opscode endpoint
2. Copy the access token to Opscode and follow deployment steps there
3. Enable the GitLab Error Tracking

What might happen if this goes wrong?

Enabling and disabling the configuration flag works as a feature enable/disable functionality (currently there are other feature flags dependent but when those are removed this will be the one application flag to turn error tracking off).

This is just additional configuration. It doesn't impact current code that is also not behing feature flags

What can we monitor to detect problems with this?

Config page should still work

What can we check for monitoring production after rollouts?

Access Admin > Settings > General. It should render correctly and save should also work without validation errors.

Rollout Steps

Rollout on non-production environments

• Ensure that the feature MRs have been deployed to non-production environments.
  • /chatops run auto_deploy status ecbb29ebd27d8a4de9034396149586aee61d9f9d
• Enable the feature globally on non-production environments.
  • /chatops run feature set gitlab_error_tracking 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 ecbb29ebd27d8a4de9034396149586aee61d9f9d
• Enable the feature globally on production:
  • /chatops run feature set gitlab_error_tracking 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.
• 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

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_observability).

• Enable the feature globally on production environment.
  • /chatops run feature set gitlab_error_tracking 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 included in the release package. If the merge request was deployed before the monthly release was tagged, the feature can be officially announced in a release blog post.
  • /chatops run release check <merge-request-url> <milestone>
• Consider cleaning up the feature flag from all environments by running these chatops command in #production channel. Otherwise these settings may override the default enabled.
  • /chatops run feature delete <feature-flag-name> --dev --staging --staging-ref --production
• 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 <feature-flag-name>".
  • 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.

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 gitlab_error_tracking 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 included in the release package. If the merge request was deployed before the monthly release was tagged, the feature can be officially announced in a release blog post.
  • /chatops run release check <merge-request-url> <milestone>
• Close the feature issue to indicate the feature will be released in the current milestone.
• If not already done, clean up the feature flag from all environments by running these chatops command in #production channel:
  • /chatops run feature delete <feature-flag-name> --dev --staging --staging-ref --production
• Close this rollout issue.

Rollback Steps

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

/chatops run feature set gitlab_error_tracking false