This task describes how to configure Istio to expose a service outside of the service mesh cluster, using the Kubernetes Ingress Resource.
Before you begin
Follow the instructions in the Before you begin and Determining the ingress IP and ports sections of the Ingress Gateways task.
Configuring ingress using an Ingress resource
A Kubernetes Ingress Resources exposes HTTP and HTTPS routes from outside the cluster to services within the cluster.
Let’s see how you can configure a
Ingress on port 80 for HTTP traffic.
$ kubectl apply -f - <<EOF apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: annotations: kubernetes.io/ingress.class: istio name: ingress spec: rules: - host: httpbin.example.com http: paths: - path: /status/* backend: serviceName: httpbin servicePort: 8000 EOF
kubernetes.io/ingress.classannotation is required to tell the Istio gateway controller that it should handle this
Ingress, otherwise it will be ignored.
Access the httpbin service using curl:
$ curl -s -I -HHost:httpbin.example.com "http://$INGRESS_HOST:$INGRESS_PORT/status/200" HTTP/1.1 200 OK server: istio-envoy ...
Note that you use the
-Hflag to set the Host HTTP header to “httpbin.example.com”. This is needed because the
Ingressis configured to handle “httpbin.example.com”, but in your test environment you have no DNS binding for that host and are simply sending your request to the ingress IP.
Access any other URL that has not been explicitly exposed. You should see an HTTP 404 error:
$ curl -s -I -HHost:httpbin.example.com "http://$INGRESS_HOST:$INGRESS_PORT/headers" HTTP/1.1 404 Not Found ...
Ingress supports specifying TLS settings. This is supported by Istio, but the referenced
Secret must exist in the namespace of the
istio-ingressgateway deployment (typically
istio-system). cert-manager can be used to generate these certificates.
Specifying path type
By default, Istio will treat paths as exact matches, unless they end in
.*, in which case they will become prefix matches. Other regular expressions are not supported.
In Kubernetes 1.18, a new field,
pathType, was added. This allows explicitly declaring a path as
In Kubernetes 1.18, a new resource,
IngressClass, was added, replacing the
kubernetes.io/ingress.class annotation on the
Ingress resource. If you are using this resource, you will need to set the
controller field to
istio.io/ingress-controller. For example:
apiVersion: networking.k8s.io/v1beta1 kind: IngressClass metadata: name: istio spec: controller: istio.io/ingress-controller --- apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: name: ingress spec: ingressClassName: istio rules: - host: httpbin.example.com http: paths: - path: / pathType: Prefix backend: serviceName: httpbin servicePort: 8000
Ingress configuration, and shutdown the httpbin service:
$ kubectl delete ingress ingress $ kubectl delete --ignore-not-found=true -f @samples/httpbin/httpbin.yaml@