Set main as the default branch

[TineoC]

This migration follows the official Kubernetes Default Branch Migration guide.

Phase 1: Pre-Rename (Preparation)

• Mailing List Announcement: Send an email to the SIG ContribEx mailing list (kubernetes-sig-contribex@googlegroups.com) announcing the planned migration.
• Slack Coordination: Join the #github-management channel on Kubernetes Slack to inform them of the upcoming rename and ask for any repo-specific advice (specifically for Netlify).
• PR 1 (Contributor Site): PR #712 - Update _PULL_BASE_REF to main in cloudbuild.yaml.
• PR 2 (Test-Infra): test-infra PR #36931 - Update config/jobs/image-pushing/k8s-staging-contributor-site.yaml.
  • Action: Add main to the branches list for all jobs to ensure CI coverage during the transition.
• Internal Approval: Obtain approval from at least one other root approver (e.g., jberkus, jeefy, mrbobbytables) on this tracking issue.

Phase 2: Execution (Disruption Window)

• Final GitHub Team Approval: Assign @kubernetes/owners (GitHub Management Team) to this issue for final sign-off.
• Netlify Coordination: Coordinate with the GitHub Management Team in #github-management to update the Netlify production branch setting to main.
• Branch Rename: Once GitHub Management gives the green light, use the GitHub UI (Settings > Branches) to rename master to main.

Phase 3: Post-Rename (Cleanup)

• PR 3 (Test-Infra): test-infra PR #36932 - Create a follow-up PR in kubernetes/test-infra to remove now-obsolete master branch references for contributor-site.
• PR 4 (Contributor Site):
  • PR #714 - Update CNCF Foundation and Memorials links to main.
  • PR #715 - Update kubernetes/community links to main.
  • Update other repository links (k/enhancements, test-infra, etc.) only after they migrate to main.
• Final Announcement: Send a second email to kubernetes-sig-contribex@googlegroups.com with instructions for contributors to update their local clones:

  git checkout master
  git branch -m master main
  git fetch origin
  git branch -u origin/main main
  git remote set-head origin -a

Contacts Summary

• SIG ContribEx: kubernetes-sig-contribex@googlegroups.com
• GitHub Management: @kubernetes/owners on GitHub.
• Slack: #github-management on Kubernetes Slack.

[lmktfy]

/triage accepted

[jberkus]

Other than changing the default branch and changing the branch that netlify builds from, what needs to be done?

[TineoC]

@lmktfy @jberkus, if you have experience with doing this in other repos, please let me know if the plans look accurate, especially in the non-coding portions of the plan

[lmktfy]

No Kubernetes experience for this work. I have renamed default branches in other contexts.

Thinks to consider:

• are there any branch protection rules to configure? In big organizations / projects those are often managed declaratively.
• docs and READMEs may need to change
• if we have open PRs that merge master into a different branch, that needs care
  • we don't
• how will we notify people to change their ways of working?