Amusingly, the article references Kubernetes and its growing pains a couple times, but fails to mention that it adopted Reviewable (on top of GitHub) for doing

Amusingly, the article references Kubernetes and its growing pains a couple times, but fails to mention that it adopted Reviewable (on top of GitHub) for doing more complicated code reviews. I don't know if Reviewable would scale to kernel development -- and it certainly doesn't support offline work, etc. -- but at least Kubernetes seems to be doing all right with it. (Disclosure: I'm the founder of Reviewable.)