PodDisruptionBudget maxUnavailable Non-Zero

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: pdb-maxunavailable
 5  annotations:
 6    policies.kyverno.io/title: PodDisruptionBudget maxUnavailable Non-Zero
 7    policies.kyverno.io/category: Other
 8    kyverno.io/kyverno-version: 1.9.0
 9    kyverno.io/kubernetes-version: "1.24"
10    policies.kyverno.io/subject: PodDisruptionBudget
11    policies.kyverno.io/description: >-
12      A PodDisruptionBudget which sets its maxUnavailable value to zero prevents
13      all voluntary evictions including Node drains which may impact maintenance tasks.
14      This policy enforces that if a PodDisruptionBudget specifies the maxUnavailable field
15      it must be greater than zero.      
16spec:
17  validationFailureAction: audit
18  background: false
19  rules:
20    - name: pdb-maxunavailable
21      match:
22        any:
23          - resources:
24              kinds:
25                - PodDisruptionBudget
26      validate:
27        message: "The value of maxUnavailable must be greater than zero."
28        pattern:
29          spec:
30            =(maxUnavailable): ">0"