apiVersion: kyverno.io/v1alpha1
kind: ClusterPolicy
metadata:
  name: restrict-nodeport
  annotations:
    policies.kyverno.io/category: Workload Isolation
    policies.kyverno.io/description: A Kubernetes service of type NodePort uses a 
      host port to receive traffic from any source. A 'NetworkPolicy' resource cannot be used 
      to control traffic to host ports. Although 'NodePort' services can be useful, their use 
      must be limited to services with additional upstream security checks.
spec:
  rules:
  - name: validate-nodeport
    match:
      resources:
        kinds:
        - Service
    validate:
      message: "Services of type NodePort are not allowed"
      pattern: 
        spec:
          type: "!NodePort"