istio.io/ingress.md at dda05ff6885973e08e29b1e31c8dceeb187ee0a8

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title	overview	order	layout	type
Enabling Ingress Traffic	Describes how to configure Istio to expose a service outside of the service mesh.	30	docs	markdown

This task describes how to configure Istio to expose a service outside of the service mesh cluster. In a Kubernetes environment, Istio uses Kubernetes Ingress Resources to configure ingress behavior.

Before you begin

Setup Istio by following the instructions in the Installation guide.
Make sure your current directory is the istio directory.
Start the httpbin sample, which will be used as the destination service to be exposed externally.
```
kubectl apply -f <(istioctl kube-inject -f samples/apps/httpbin/httpbin.yaml)
```

Configuring ingress (HTTP)

Create the Ingress Resource for the httpbin service

cat <<EOF | kubectl create -f -
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: simple-ingress
  annotations:
    kubernetes.io/ingress.class: istio
spec:
  rules:
  - http:
      paths:
      - path: /headers
        backend:
          serviceName: httpbin
          servicePort: 8000
      - path: /delay/.*
        backend:
          serviceName: httpbin
          servicePort: 8000
EOF

Notice that in this example we are only exposing httpbin's two endpoints: /headers as an exact URI path and /delay/ using an URI prefix.

Determine the ingress URL:

If your cluster is running in an environment that supports external load balancers, use the ingress' external address:

kubectl get ingress simple-ingress -o wide

NAME             HOSTS     ADDRESS                 PORTS     AGE
simple-ingress   *         130.211.10.121          80        1d

export INGRESS_URL=130.211.10.121

If load balancers are not supported, use the ingress controller pod's hostIP:

kubectl get po -l istio=ingress -o jsonpath='{.items[0].status.hostIP}'

169.47.243.100

along with the istio-ingress service's nodePort for port 80:

kubectl get svc istio-ingress

NAME            CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
istio-ingress   10.10.10.155   <pending>     80:31486/TCP,443:32254/TCP   32m

export INGRESS_URL=169.47.243.100:31486

Access the httpbin service using curl:

curl http://$INGRESS_URL/headers

{
  "headers": {
    "Accept": "*/*", 
    "Content-Length": "0", 
    "Host": "httpbin.default.svc.cluster.local:8000", 
    "User-Agent": "curl/7.51.0", 
    "X-Envoy-Expected-Rq-Timeout-Ms": "15000", 
    "X-Request-Id": "3dd59054-6e26-4af5-87cf-a247bc634bab"
  }
}

Configuring secure ingress (HTTPS)

Generate keys if necessary

A private key and certificate can be created for testing using OpenSSL.

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /tmp/tls.key -out /tmp/tls.crt -subj "/CN=foo.bar.com"

Create the secret using kubectl

kubectl create secret tls ingress-secret --key /tmp/tls.key --cert /tmp/tls.crt

Create the Ingress Resource for the httpbin service

cat <<EOF | kubectl create -f -
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: secured-ingress
  annotations:
    kubernetes.io/ingress.class: istio
spec:
  tls:
    - secretName: ingress-secret
  rules:
  - http:
      paths:
      - path: /ip
        backend:
          serviceName: httpbin
          servicePort: 8000
EOF

Notice that in this example we are only exposing httpbin's /ip endpoint.

Note: Envoy currently only allows a single TLS secret in the ingress since SNI is not yet supported.

Determine the secure ingress URL:

If your cluster is running in an environment that supports external load balancers, use the ingress' external address:

kubectl get ingress secured-ingress -o wide

NAME              HOSTS     ADDRESS                 PORTS     AGE
secured-ingress   *         130.211.10.121          80, 443   1d

export SECURE_INGRESS_URL=130.211.10.121

Note that in this case SECURE_INGRESS_URL should be the same as INGRESS_URL that you set previously.

If load balancers are not supported, use the ingress controller pod's hostIP:

kubectl get po -l istio=ingress -o jsonpath='{.items[0].status.hostIP}'

169.47.243.100

along with the istio-ingress service's nodePort for port 443:

kubectl get svc istio-ingress

NAME            CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
istio-ingress   10.10.10.155   <pending>     80:31486/TCP,443:32254/TCP   32m

export SECURE_INGRESS_URL=169.47.243.100:32254

Access the secured httpbin service using curl:

curl -k https://$SECURE_INGRESS_URL/ip

{
  "origin": "129.42.161.35"
}

Setting Istio rules on an edge service

Similar to inter-cluster requests, Istio routing rules can also be set for edge services that are called from outside the cluster. To illustrate we will use istioctl to set a timeout rule on calls to the httpbin service.

Invoke the httpbin /delay endpoint you exposed previously:

time curl -o /dev/null -s -w "%{http_code}\n" http://$INGRESS_URL/delay/5

200

real    0m5.024s
user    0m0.003s
sys     0m0.003s

The request should return 200 (OK) in approximately 5 seconds.

Use istioctl to set a 3s timeout on calls to the httpbin service

cat <<EOF | istioctl create
type: route-rule
name: httpbin-3s-rule
spec:
  destination: httpbin.default.svc.cluster.local
  http_req_timeout:
    simple_timeout:
      timeout: 3s
EOF

Note that you may need to change the default namespace to the namespace of the httpbin application.

Wait a few seconds, then issue the curl request again:
```
time curl -o /dev/null -s -w "%{http_code}\n" http://$INGRESS_URL/delay/5
```
```
504

real    0m3.149s
user    0m0.004s
sys     0m0.004s
```
This time a 504 (Gateway Timeout) appears after 3 seconds. Although httpbin was waiting 5 seconds, Istio cut off the request at 3 seconds.

Note: HTTP fault injection (abort and delay) is not currently supported by ingress proxies.

Understanding ingresses

Ingresses provide gateways for external traffic to enter the Istio service mesh and make the traffic management and policy features of Istio available for edge services.

In the preceding steps we created a service inside the Istio service mesh and showed how to expose both HTTP and HTTPS endpoints of the service to external traffic. We also showed how to control the ingress traffic using an Istio route rule.

Cleanup

Remove the secret, Ingress Resource definitions and Istio rule.

istioctl delete route-rule httpbin-3s-rule 
kubectl delete ingress simple-ingress secured-ingress 
kubectl delete secret ingress-secret

Shutdown the httpbin service.

kubectl delete -f samples/apps/httpbin/httpbin.yaml

What's next

Learn more about routing rules.
Learn how to expose external services by enabling egress traffic.

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