kyverno/examples/demo/7_container_security_context/policy.yaml

apiVersion : kyverno.io/v1alpha1
kind: Policy
metadata:
  name: container-security-context
spec:
  rules:
  - name: validate-user-privilege
    resource:
      kinds:
      - Deployment
      selector :
        matchLabels:
          app.type: prod
    validate:
      message: "validate container security contexts"
      pattern:
        spec:
          template:
            spec:
              containers:
              - securityContext:
                  runAsNonRoot: true
                  allowPrivilegeEscalation: false
                  # fields can be customized
                  # privileged: false
                  # readOnlyRootFilesystem: true