Changes in volumeClaimTemplate triggers creation of a new statefulset

Adding a volumeClaimTemplate, or existing an existing one leads to the re-creation of statefulset -> all pods are immediately terminated and route is unavailable until some of the pods is ready again.

reproduce

• deploy operator

  ./build/run-openshift.sh

• deploy updatedquickstart project from operator repository

  cat deploy/crds/quickstart-cr.yaml
  apiVersion: wildfly.org/v1alpha1
  kind: WildFlyServer
  metadata:
    name: quickstart
  spec:
    applicationImage: "quay.io/wildfly-quickstarts/wildfly-operator-quickstart:18.0"
    replicas: 2
    storage:
      volumeClaimTemplate:
        spec:
          resources:
            requests:
              storage: 1Mi
  oc apply -f deploy/crds/quickstart-cr.yaml

• wait for both replicas to be ready & print ss creation timestamp & verify application readiness

  oc get pods
  NAME                                READY   STATUS    RESTARTS   AGE
  quickstart-0                        1/1     Running   0          2m48s
  quickstart-1                        1/1     Running   0          2m48s
  wildfly-operator-54455dbcd8-flnd4   1/1     Running   0          69m
  
  oc get statefulset.apps/quickstart --template={{.metadata.creationTimestamp}}
  2019-10-17T13:55:03Z
  
  curl quickstart-route-wildfly.apps-crc.testing
  {"ip":"10.128.1.36"}
  

• edit the storage field (e.g. storage: 1Mi -> storage: 2Mi)
• notice the both pods are terminating, stateful set creation timestamp has changed and application route is not available until one of the pods will start again (could take a minute)

  oc get pods
  NAME                                READY   STATUS        RESTARTS   AGE
  quickstart-0                        1/1     Terminating   0          5m42s
  quickstart-1                        1/1     Terminating   0          5m42s
  wildfly-operator-54455dbcd8-flnd4   1/1     Running       0          72m
  
  oc get statefulset.apps/quickstart --template={{.metadata.creationTimestamp}}
  2019-10-17T14:00:44Z
  
  curl quickstart-route-wildfly.apps-crc.testing
  ...
  Application is not available
  ...