Operator crashes when creating vcheck pod if an invalid value of topologySpreadConstraints.whenUnsatisfiable is given

What version of operator are you using? commit 561cf47d783c368fd8795acb82a5a39099a35984 (HEAD -> master)

What operating system and processor architecture are you using (kubectl version)? Ubuntu. 20.04

What did you do?

I find that crdb-operator will crash when starting the vcheck job pod if whenUnsatisfiable under topologySpreadConstraints has an invalid value.

I created the cluster by applying the following custom resource file, note that the value of whenUnsatisfiable is wrongly spelled:

apiVersion: crdb.cockroachlabs.com/v1alpha1
kind: CrdbCluster
metadata:
  name: test-cluster
spec:
  additionalLabels:
    crdb: is-cool
  dataStore:
    pvc:
      spec:
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 1Gi
        volumeMode: Filesystem
  image:
    name: cockroachdb/cockroach:v21.2.10
  nodes: 3
  resources:
    limits:
      cpu: 2
      memory: 2Gi
    requests:
      cpu: 100m
      memory: 1Gi
  tlsEnabled: true
  topologySpreadConstraints:
  - maxSkew: 3
    topologyKey: MYKEY
    whenUnsatisfiable: DoNotScedule

(All files were applied using kubectl apply -f <filename> -n cockroach-operator-system)

What did you see?

The program crashed.

Comments

I checked the log of the operator and I found that a nil pointer dereference happened.

It seems that when whenUnsatisfiable is assigned with an invalid value, the operator cannot find the vcheck job pod while it expects to find it, leading to a nil pointer dereference at this line where Selector is nil while Selector.MatchLabels is accessed.