# Restrict ingress classes
It can be useful to restrict Ingress resources to a set of known ingress classes that are allowed in the cluster. You can customize this policy to allow ingress classes that are configured in the cluster.
## Policy YAML
[restrict_ingress_classes.yaml](more/restrict_ingress_classes.yaml)
````yaml
apiVersion : kyverno.io/v1alpha1
kind: ClusterPolicy
metadata:
name: restrict-ingress-classes
spec:
rules:
- name: validate-ingress
match:
resources:
kinds:
- Ingress
validate:
message: "Unknown ingress class"
pattern:
annotations:
kubernetes.io/ingress.class: "F5 | nginx"
````