[RFE] Implement CODEOWNERS file for standardized PR review workflow

[John15321]

Current situation

Currently, reviewer assignment for pull requests is handled manually in the Flatcar repositories. Contributors or maintainers must remember to add the correct team (e.g., flatcar-maintainers, nebraska-maintainers) as reviewers. This process is inconsistent and can be easily missed, especially by external contributors, newcomers, or those unfamiliar with the team structure. For newcomers in particular, this is a significant challenge, as they often do not have the required privileges to assign PR reviewers, leading to PRs being overlooked or delayed.

Impact

• Pull requests, especially from external contributors and newcomers, may not receive timely or appropriate review, which can delay merges and reduce code quality assurance.
• Contributors without the necessary privileges are unable to assign reviewers at all, increasing frustration and onboarding time.
• The process is error-prone, burdensome, and does not scale well as the number of contributors and repositories increases.

Ideal future situation

A CODEOWNERS file is present in the repository (or at the org level), which automatically assigns the appropriate GitHub teams as reviewers for all PRs. This ensures that the correct maintainers are always notified of code review requests, regardless of contributor privilege level, streamlining the review process and improving code quality. The CODEOWNERS entries are aligned with the MAINTAINERS.md file as appropriate.

Implementation options

This would work as follows:

For most repositories (with flatcar-maintainers as maintainers):

• CODEOWNERS file would contain just the flatcar-maintainers group
• Every PR automatically assigned for review to all flatcar-maintainers
• This works well for repos that rarely receive contributions

For high-activity repositories (like scripts with more contributors):

• Individual GitHub Teams would be created (e.g., flatcar-scripts)
• These teams serve as focused tags that maintainers can join (arbitrarily many)
• CODEOWNERS would reference these specific teams
• Reduces noise and allows people to focus attention where needed
• Ensures we allocate attention to every PR across the org as best as possible

For Nebraska-specific repositories:

• Use nebraska-maintainers as appropriate

The exact number of teams and initial membership is open for discussion. Coordinate with maintainers to keep CODEOWNERS and MAINTAINERS.md aligned as much as possible.

Additional information

• This subissue is part of the standardization efforts described in [RFE] Standardize Pull Request, Merging workflow and branch protection rules #1714.
• Further requirements and discussion can be found in [RFE] Setup CODEOWNERS file #1665.
• GitHub CODEOWNERS documentation: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners

EDIT:

Final chart with specific assigments (everything else, has flatcar-maintainers groups set as the default reviewers):

Teams	nebraska-flatcar	flatcar-integrations	flatcar-communication	flatcar-ci	flatcar-infra
People	as is = illume, t-lo, joaquimrocha, pothos, jepio, miao0miao, tormath1, ervcz	t-lo, danzatt, tormath1, John15321, pothos	tormath1, sayanchowdhury, ervcz, John15321	tormath1, jepio, sayanchowdhury, chewi, pothos, jepio, dongsupark	tormath1, John15321, sayanchowdhury, jepio, pothos, dongsupark
Repositories	as is = flatcar-maintainer-private, flatcar-website, go-omaha, nebraska, nebraska-update-agent, ue-rs, update_engine	sysext-bakery, flatcar-app-minecraft,flatcar-app-jitsi	flatcar-website, flatcar-socials	mantle, jenkins-os, jenkins-secret	flatcar-linux-build-secrets, flatcar-linux-infra-secrets, flatcar-linux-infra

[chewi]

I'm still happy following what was said in #1665.

[John15321]

I'm still happy following what was said in #1665.

Could you elaborate? Sorry just quite a bit happened in that one issue

[John15321]

Draft (To be edited further):

Teams	flatcar-scripts	flatcar-website	nebraska-flatcar	flatcar-sysext-bakery	flatcar-mantle	flatcar-jenkins	flatcar-apps	flatcar-infrastructure
People	krnowak, tormath1	tormath1, sayanchowdhury, ervcz, chewi	as is	t-lo, tormath1	chewi, tormath1, danzatt, krnowak, John15321	tormath1, jepio, sayanchowdhury, chewi	John15321, t-lo	?
Repositories	scripts	flatcar-website	as is	sysext-bakery	mantle	jenkins-os, jenkins-secret	flatcar-app-minecraft,flatcar-app-jitsi	?

This is just a quick lookup at most contributed to repos, and people that most contribute to them, so please DO provide your feedback here

[chewi]

I'm still happy following what was said in #1665.

Could you elaborate? Sorry just quite a bit happened in that one issue

Mathieu made the point that he likes to see what is going on elsewhere in Flatcar, but I took your point that the volume of traffic is quite high. I also totally agreed with your point that if too many people receive these requests, there is a good chance no will act on them because they will expect someone else to do it.

[chewi]

This is just a quick lookup at most contributed to repos, and people that most contribute to them, so please DO provide your feedback here

I really want to be on flatcar-scripts. Less so on flatcar-website, but I don't mind.