kyverno/examples/best_practices/validate_host_path.yaml

# apiVersion : kyverno.io/v1alpha1
# kind: Policy
# metadata:
#   name: validate-host-dirs
# spec:
#   rules:
#   - name: validate-host-path
#     match:
#       resources:
#         kinds:
#         - Pod
#     validate:
#       message: "Host path is not allowed"
#       pattern:
#         spec:
#           volumes:
#           - (name): "*"
#             hostPath:
#               path: ""

apiVersion : kyverno.io/v1alpha1
kind: Policy
metadata:
  name: validate-host-path
spec:
  rules:
  - name: validate-host-path
    match:
      resources:
        kinds:
        - Pod
    validate:
      message: "Host path '/var/lib/' is not allowed"
      pattern:
        spec:
          volumes:
          - (name): "*"
            +(hostPath):
              path: "!/var/lib/*"