generate.yaml

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: "default"
spec:
  rules:
  - name: "default-deny"
    match:
      resources: 
        kinds:
        - Namespace
        name: "*"
    exclude:
      namespaces:
        - "kube-system"
        - "default"
        - "kube-public"
        - "kyverno"
    generate: 
      kind: NetworkPolicy
      name: default-deny-all-traffic
      namespace: "{{request.object.metadata.namespace}}" 
      data:  
        spec:
          podSelector: {}
          policyTypes: 
          - Ingress
          - Egress