kyverno/test/scenarios/policy_validate_imageRegistries.yaml

apiVersion : kyverno.io/v1alpha1
kind: ClusterPolicy
metadata:
  name: check-registries
spec:
  rules:
  - name: check-registries
    match:
      resources:
        kinds:
        - Deployment
        - StatefulSet
        selector:
          matchLabels:
            app: nirmata-nginx
    validate:
      message: "Registry is not allowed"
      pattern:
        spec:
          template:
            spec:
              containers:
              - name: "*"
                # Check allowed registries
                image: "*nirmata* | https://private.registry.io/*"