KCM and KS need to gracefully terminate so the next replica can take over during a rollout. Graceful termination is important for giving up the lease, so another replica can become the leader without waiting for the lease to expire.
KCM is especially important to be available as much as we can because it runs the endpoints controller which has to notice pods going down / rolling out and update service ASAP to stop sending traffic there.
The PR is already in the queue.
PR is awaiting QA pre-verification https://github.com/openshift/origin/pull/25536#issuecomment-714639556
Checked with 4.5.0-0.ci.test-2020-10-23-075611-ci-ln-j1qrj4k, the KS will renew lead within 10s .
I1023 08:51:01.440871 1 server.go:253] Requested to terminate. Exiting.
I1023 08:51:04.103558 1 leaderelection.go:252] successfully acquired lease openshift-kube-scheduler/kube-scheduler
I1023 08:55:35.733465 1 server.go:253] Requested to terminate. Exiting.
I1023 08:55:37.539562 1 leaderelection.go:252] successfully acquired lease openshift-kube-scheduler/kube-scheduler
Checked with 4.5.0-0.ci.test-2020-10-23-075611-ci-ln-j1qrj4k, the KCM will renew lead within 10s .
steps followed to verify the bug:
1) check KCM leader
2) move kube-controller-manager-config.yaml from /etc/kubernetes/manifests to some other directory
3) check logs of all kcm pods
Node on which file was moved you will see a message as below and with in 10 seconds you should see another replica becoming kcm leader.
I1023 09:00:38.120509 1 controllermanager.go:301] Requested to terminate. Exiting.
I1023 09:00:42.292918 1 leaderelection.go:252] successfully acquired lease kube-system/kube-controller-manager
I1023 09:04:15.560848 1 controllermanager.go:301] Requested to terminate. Exiting.
I1023 09:04:16.609500 1 leaderelection.go:252] successfully acquired lease kube-system/kube-controller-manager
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (OpenShift Container Platform 4.5.18 bug fix update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.