Automatic merge from submit-queue
rkt: Do not run rkt pod inside a pre-created netns when network plugin is no-op
This fixed a panic where the returned pod network status is nil. (Fix#26540)
Also this makes lkvm stage1 able to run inside a user defined network, where the network name needs to be 'rkt.kubernetes.io'. A temporal solution to solve the network issue for lkvm stage1.
Besides, I fixed minor issues such as passing the wrong pod UID when cleaning up the netns file.
/cc @euank @pskrzyns @jellonek @kubernetes/sig-node
I tested with no networkplugin locally, works fine.
As a reminder, we need to document this in the release.https://github.com/kubernetes/kubernetes/issues/26201