Verified this by upgrading from 4.5.0-0.nightly-2020-10-21-224736 to 4.6.0-0.nightly-2020-10-22-034051. worker node could join the cluster.
1. Provision a 4.5 cluster
2. Create a PDB for the deployment. Node drain would not succeed because PDB prevents it
3. Oc adm upgrade
4. Wait looking at `oc -n openshift-machine-config-operator get ds/machine-config-server` for the new MCS to roll out; you can use e.g. `oc -n openshift-machine-config-operator logs pod/machine-config-server-xyz` and verify it shows its version as 4.6.
5. Verify in `oc get machineconfigpool/worker` that the pool is still progressing (you have at least one worker blocked)
6. Try scaling up a worker machineset via e.g. `oc -n openshift-machine-api scale machineset/worker-xyz`
$ oc get clusterversion
NAME VERSION AVAILABLE PROGRESSING SINCE STATUS
version 4.6.0-0.nightly-2020-10-22-034051 True False 7m17s Cluster version is 4.6.0-0.nightly-2020-10-22-034051
$ oc get machine
NAME PHASE TYPE REGION ZONE AGE
zhsun22aws1-4d6b9-master-0 Running m4.xlarge us-east-2 us-east-2a 3h39m
zhsun22aws1-4d6b9-master-1 Running m4.xlarge us-east-2 us-east-2b 3h39m
zhsun22aws1-4d6b9-master-2 Running m4.xlarge us-east-2 us-east-2c 3h39m
zhsun22aws1-4d6b9-worker-us-east-2a-6vblc Running m4.large us-east-2 us-east-2a 9m27s
zhsun22aws1-4d6b9-worker-us-east-2aa-m8d4t Running m5.4xlarge us-east-2 us-east-2a 78m
zhsun22aws1-4d6b9-worker-us-east-2b-2r695 Running m4.large us-east-2 us-east-2b 9m27s
zhsun22aws1-4d6b9-worker-us-east-2b-s6rmx Running m4.large us-east-2 us-east-2b 3h26m
zhsun22aws1-4d6b9-worker-us-east-2c-44fkq Running m4.large us-east-2 us-east-2c 3h26m
$ oc get node
NAME STATUS ROLES AGE VERSION
ip-10-0-144-169.us-east-2.compute.internal Ready worker 24m v1.19.0+d59ce34
ip-10-0-154-83.us-east-2.compute.internal Ready master 3h50m v1.19.0+d59ce34
ip-10-0-159-91.us-east-2.compute.internal Ready worker 94m v1.19.0+d59ce34
ip-10-0-177-122.us-east-2.compute.internal Ready worker 3h41m v1.19.0+d59ce34
ip-10-0-177-223.us-east-2.compute.internal Ready worker 23m v1.19.0+d59ce34
ip-10-0-180-169.us-east-2.compute.internal Ready master 3h50m v1.19.0+d59ce34
ip-10-0-200-202.us-east-2.compute.internal Ready master 3h50m v1.19.0+d59ce34
ip-10-0-209-66.us-east-2.compute.internal Ready worker 3h41m v1.19.0+d59ce34
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 4.6 GA Images), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.