[Feature flag] Enable wiki create page gitaly RPC

Summary

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

Once the feature flag is rolled out, we can remove the associated code in https://gitlab.com/gitlab-org/gitlab/blob/master/lib/gitlab/git/wiki.rb#L73 and the gitaly service.

Owners

• Team: ~"group::editor"
• Most appropriate slack channel to reach out to: #g_create_editor
• Best individual to reach out to: @cwoolley-gitlab
• PM: @ericschurter

Stakeholders

Expectations

What are we expecting to happen?

Wiki creation will work normally.

When is the feature viable?

As soon as it is deployed and the flag is enabled.

What might happen if this goes wrong?

Wiki creation may fail.

What can we monitor to detect problems with this?

Consider mentioning checks for 5xx errors or other anomalies like an increase in redirects (302 HTTP response status)

1. Sentry for wiki: https://sentry.gitlab.net/gitlab/gitlabcom/?query=is%3Aunresolved+wiki
2. Sentry for rpc: https://sentry.gitlab.net/gitlab/gitlabcom/?query=is%3Aunresolved+rpc
3. Issues reported for wikis.

What can we check for monitoring production after rollouts?

Consider adding links to check for Sentry errors, Production logs for 5xx, 302s, etc.

Same as above.

Rollout Steps

Rollout on non-production environments

• Ensure that the feature MRs have been deployed to non-production environments.
  • /chatops run auto_deploy status 660d14c264116df2e7d64683cd44a4040843dd9e
• Enable the feature globally on non-production environments.
  • /chatops run feature set gitaly_replace_wiki_create_page true --dev
  • /chatops run feature set gitaly_replace_wiki_create_page 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 660d14c264116df2e7d64683cd44a4040843dd9e
• If you're using project-actor, you must enable the feature on these entries:
  • [-] /chatops run feature set --project=gitlab-org/gitlab gitaly_replace_wiki_create_page true
  • [-] /chatops run feature set --project=gitlab-org/gitlab-foss gitaly_replace_wiki_create_page true
  • [-] /chatops run feature set --project=gitlab-com/www-gitlab-com gitaly_replace_wiki_create_page true
• If you're using group-actor, you must enable the feature on these entries:
  • /chatops run feature set --group=gitlab-org gitaly_replace_wiki_create_page true
  • /chatops run feature set --group=gitlab-com gitaly_replace_wiki_create_page true
• If you're using user-actor, you must enable the feature on these entries:
  • [-] /chatops run feature set --user=<your-username> gitaly_replace_wiki_create_page 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_TEAM_NAME).

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

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 gitaly_replace_wiki_create_page feature flag. Ask for review and merge it: Remove gitaly_replace_wiki_create_page flag (!88624 - merged)
  • 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 5d8fa525
• 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 gitaly_replace_wiki_create_page --dev
  • /chatops run feature delete gitaly_replace_wiki_create_page --staging
  • /chatops run feature delete gitaly_replace_wiki_create_page
• Close this rollout issue.

Rollback Steps

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

/chatops run feature set gitaly_replace_wiki_create_page false

Availability and Testing

Please ensure package-and-qa is run on the MR that default enables the feature flag and a SET reviewer assigned on the feature flag removal MR (as we do not have an option to run the full suite there).