istio.io/content/help/faq/traffic-management/ingress-with-no-route-rules.md

title	weight
Can I use standard Ingress specification without any route rules?	40

Simple ingress specifications, with host, TLS, and exact path based matches will work out of the box without the need for route rules. However, note that the path used in the ingress resource should not have any . characters.

For example, the following ingress resource matches requests for the example.com host, with /helloworld as the URL.

cat <<EOF | kubectl create -f -
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: simple-ingress
annotations:
  kubernetes.io/ingress.class: istio
spec:
rules:
- host: example.com
  http:
    paths:
    - path: /helloworld
      backend:
        serviceName: myservice
        servicePort: grpc
EOF

However, the following rules will not work because it uses regular expressions in the path and uses ingress.kubernetes.io annotations:

cat <<EOF | kubectl create -f -
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: this-will-not-work
annotations:
  kubernetes.io/ingress.class: istio
  # Ingress annotations other than ingress class will not be honored
  ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: example.com
  http:
    paths:
    - path: /hello(.*?)world/
      backend:
        serviceName: myservice
        servicePort: grpc
EOF