verified with 4.5.0-0.nightly-2021-03-15-055437 $ oc get clusterversion NAME VERSION AVAILABLE PROGRESSING SINCE STATUS version 4.5.0-0.nightly-2021-03-15-055437 True False 34m Cluster version is 4.5.0-0.nightly-2021-03-15-055437 ## in first terminal, create a test pod, and rsh into the test pod, run the infinite loop to measure time for DNS lookup $ oc create -f https://raw.githubusercontent.com/openshift/verification-tests/master/testdata/networking/aosqe-pod-for-ping.json pod/hello-pod created $ pod/hello-pod created bash: pod/hello-pod: No such file or directory $ oc rsh hello-pod / # while (true); do time getent hosts kubernetes.default.svc.cluster.local; sleep 1; done 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.02s user 0m 0.00s sys 0m 0.00s 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.00s user 0m 0.00s sys 0m 0.00s 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.00s user 0m 0.00s sys 0m 0.00s <----snip-----> ##In second terminal, reboot one of the master nodes $ oc debug node/ci-ln-7y7qydt-f76d1-8qx7l-master-0 Starting pod/ci-ln-7y7qydt-f76d1-8qx7l-master-0-debug ... To use host binaries, run `chroot /host` Pod IP: 10.0.0.5 If you don't see a command prompt, try pressing enter. sh-4.2# chroot /host sh-4.4# reboot Terminated ### In first terminal, monitor to ensure that there is no DNS lookup delay when the master is rebooting (for about 3-5 min) <----snip-----> 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.02s user 0m 0.00s sys 0m 0.00s 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.00s user 0m 0.00s sys 0m 0.00s 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.00s user 0m 0.00s sys 0m 0.00s 172.30.0.1 kubernetes.default.svc.cluster.local kubernetes.default.svc.cluster.local real 0m 0.00s user 0m 0.00s sys 0m 0.00s <----snip-----> $ oc -n openshift-dns get ds/dns-default -oyaml <---snip---> readinessProbe: failureThreshold: 3 httpGet: path: /health port: 8080 scheme: HTTP initialDelaySeconds: 10 periodSeconds: 3 <--verified the fix with https://github.com/openshift/cluster-dns-operator/pull/242 successThreshold: 1 timeoutSeconds: 3 <--verified the fix with https://github.com/openshift/cluster-dns-operator/pull/242 <---snip--->
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 4.5.36 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. https://access.redhat.com/errata/RHBA-2021:0840