homelab-gitops/platform/kyverno/policies/generate-ns-network-baseline.yaml

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: generate-ns-network-baseline
  annotations:
    policies.kyverno.io/title: Inject Namespace Baseline CNP
    policies.kyverno.io/description: Automatically provisions a local default-deny + DNS egress CNP inside new application namespaces.
spec:
  background: true
  rules:
    - name: inject-local-cnp
      match:
        any:
          - resources:
              kinds:
                - Namespace
      exclude:
        any:
          - resources:
              namespaces:
                - default
                - kube-system
                - kube-public
                - kube-node-lease
                - argocd
                - kyverno
                - cilium-ingress
                - cilium-secrets
                - cert-manager
                - sealed-secrets
                - nfs-subdir-external-provisioner
                - monitoring
                - tekton-pipelines-resolvers
                - tekton-pipelines
      generate:
        apiVersion: cilium.io/v2
        kind: CiliumNetworkPolicy
        name: baseline-network-security
        namespace: "{{request.object.metadata.name}}"
        synchronize: true
        data:
          spec:
            endpointSelector: {}
            ingress:
              - {}
            egress:
              - toEndpoints:
                  - matchLabels:
                      k8s:io.kubernetes.pod.namespace: kube-system
                      k8s-app: kube-dns
                toPorts:
                  - ports:
                      - port: "53"
                        protocol: ANY
                    rules:
                      dns:
                        - matchPattern: "*"