Bug 2089606

Description of problem:
rook-ceph-mon-pdb pdb under openshift-storage,  currentHealthy=0, desiredHealthy=0, this would trigger PodDisruptionBudgetAtLimit alert.
# token=`oc sa get-token prometheus-k8s -n openshift-monitoring`
# oc -n openshift-monitoring exec -c prometheus prometheus-k8s-0 -- curl -k -H "Authorization: Bearer $token" 'https://thanos-querier.openshift-monitoring.svc:9091/api/v1/query?' --data-urlencode 'query=ALERTS{alertname="PodDisruptionBudgetAtLimit"}' | jq
{
  "status": "success",
  "data": {
    "resultType": "vector",
    "result": [
      {
        "metric": {
          "__name__": "ALERTS",
          "alertname": "PodDisruptionBudgetAtLimit",
          "alertstate": "firing",
          "namespace": "openshift-storage",
          "poddisruptionbudget": "rook-ceph-mon-pdb",
          "prometheus": "openshift-monitoring/k8s",
          "severity": "warning"
        },
        "value": [
          1653373189.529,
          "1"
        ]
      }
    ]
  }
}


        - alert: PodDisruptionBudgetAtLimit
          annotations:
            description: The pod disruption budget is at minimum disruptions allowed level.
              The number of current healthy pods is equal to desired healthy pods.
            summary: The pod disruption budget is preventing further disruption to pods.
          expr: |
            max by(namespace, poddisruptionbudget) (kube_poddisruptionbudget_status_current_healthy == kube_poddisruptionbudget_status_desired_healthy)
          for: 60m
          labels:
            severity: warning

# oc -n openshift-storage get pdb
NAME                MIN AVAILABLE   MAX UNAVAILABLE   ALLOWED DISRUPTIONS   AGE
rook-ceph-mon-pdb   N/A             1                 0                     21h
# oc -n openshift-storage get pdb rook-ceph-mon-pdb -oyaml
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  creationTimestamp: "2022-05-23T08:24:23Z"
  generation: 1
  name: rook-ceph-mon-pdb
  namespace: openshift-storage
  resourceVersion: "335364"
  uid: bce93fc1-1ded-4930-8535-1b67618bbf51
spec:
  maxUnavailable: 1
  selector:
    matchLabels:
      app: rook-ceph-mon
status:
  conditions:
  - lastTransitionTime: "2022-05-23T09:28:36Z"
    message: ""
    observedGeneration: 1
    reason: InsufficientPods
    status: "False"
    type: DisruptionAllowed
  currentHealthy: 0
  desiredHealthy: 0
  disruptionsAllowed: 0
  expectedPods: 0
  observedGeneration: 1

Version-Release number of selected component (if applicable):
4.11.0-0.nightly-2022-05-20-213928

How reproducible:
always

Steps to Reproduce:
1. check alerts
2.
3.

Actual results:
PodDisruptionBudgetAtLimit alert for openshift-storage

Expected results:
no such alert

Master Log:

Node Log (of failed PODs):

PV Dump:

PVC Dump:

StorageClass Dump (if StorageClass used by PV/PVC):

Additional info: