Restrict control plane scheduling

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: restrict-controlplane-scheduling
  annotations:
    policies.kyverno.io/title: Restrict control plane scheduling
    policies.kyverno.io/category: Sample
    policies.kyverno.io/subject: Pod
    policies.kyverno.io/minversion: 1.6.0
    policies.kyverno.io/description: Scheduling non-system Pods to control plane nodes (which run kubelet) is often undesirable because it takes away resources from the control plane components and can represent a possible security threat vector. This policy prevents users from setting a toleration in a Pod spec which allows running on control plane nodes with the taint key `node-role.kubernetes.io/master`.
spec:
  validationFailureAction: Audit
  background: true
  rules:
    - name: restrict-controlplane-scheduling-master
      match:
        any:
          - resources:
              kinds:
                - Pod
      validate:
        message: Pods may not use tolerations which schedule on control plane nodes.
        pattern:
          spec:
            "=(tolerations)":
              - key: "!node-role.kubernetes.io/master"
    - name: restrict-controlplane-scheduling-control-plane
      match:
        any:
          - resources:
              kinds:
                - Pod
      validate:
        message: Pods may not use tolerations which schedule on control plane nodes.
        pattern:
          spec:
            "=(tolerations)":
              - key: "!node-role.kubernetes.io/control-plane"