Chapter 2. Getting traffic into a mesh

Procedure

1. Create namespace called httpbin by running the following command:

   $ oc create namespace httpbin

2. Enable sidecar injection in the namespace. If you are using the InPlace upgrade strategy, run the following command:

   $ oc label namespace httpbin istio-injection=enabled

   Note

   If you are using the RevisionBased upgrade strategy, run the following commands:

   1. To find your <revision-name>, run the following command:

      $ oc get istiorevisions.sailoperator.io

      Sample output:

      NAME              TYPE    READY   STATUS    IN USE   VERSION   AGE
      default-v1-23-0   Local   True    Healthy   True    v1.23.0   3m33s

   2. Label the namespace with the revision name to enable sidecar injection:

      $ oc label namespace httpbin istio.io/rev=default-v1-23-0

3. Deploy a sample service named httpbin by running the following command:

   $ oc apply -n httpbin -f https://raw.githubusercontent.com/openshift-service-mesh/istio/refs/heads/master/samples/httpbin/httpbin.yaml

4. Create a YAML file named httpbin-gw.yaml that defines an Istio Gateway resource. This resource configures gateway proxies to expose port 80 (HTTP) for the host, httpbin.example.com.

   apiVersion: networking.istio.io/v1
   kind: Gateway
   metadata:
     name: httpbin-gateway
     namespace: httpbin
   spec:
     selector:
       istio: <gateway_name> 1
     servers:
     - port:
         number: 80
         name: http
         protocol: HTTP
       hosts:
       - httpbin.example.com 2

   1

   Set the selector to the unique label or set of labels specified in the pod template of the gateway proxy Deployment. By default, the Istio Gateway resource configuration will apply to matching gateway pods in all namespaces.

   2

   Using the hosts field, specify a list of addresses that can be used by clients when attempting to access a mesh service at the associated port.

5. Apply the YAML file by running the following command:

   $ oc apply -f httpbin-gw.yaml

6. Create a YAML file named httpbin-vs.yaml for a VirtualService. The VirtualService defines the rules that route traffic from the gateway proxy to the httpbin service.

   apiVersion: networking.istio.io/v1
   kind: VirtualService
   metadata:
     name: httpbin
     namespace: httpbin
   spec:
     hosts:
     - httpbin.example.com 1
     gateways:
     - httpbin-gateway 2
     http:
     - match:
       - uri:
           prefix: /status
       - uri:
           prefix: /headers
       route:
       - destination: 3
           port:
             number: 8000
           host: httpbin

   1

   Specify the hosts that the routing rules of the VirtualService will be applied to. The hosts specified must be exposed by the Istio Gateway resource the VirtualService is bound to.

   2

   Bind the VirtualService to the Istio Gateway resource created in the previous step by adding the Gateway name to the list of gateways.

   3

   Route matching traffic to the httpbin service deployed earlier by defining a destination that includes the host and port of the httpbin Service.

7. Apply the YAML file by running the following command:

   $ oc apply -f httpbin-vs.yaml

8. For verification purposes, create a namespace for a curl client by running the following command:

   $ oc create namespace curl

9. Deploy the curl client by running the following command:

   $ oc apply -n curl -f https://raw.githubusercontent.com/openshift-service-mesh/istio/refs/heads/master/samples/curl/curl.yaml

10. Set a CURL_POD variable with the name of the curl pod by running the following command:

    $ CURL_POD=$(oc get pods -n curl -l app=curl -o jsonpath='{.items[*].metadata.name}')

11. Using the curl client, send a request to the /headers endpoint of the httpbin application through the ingress gateway Service resource. Set the Host header of the request to httpbin.example.com to match the host that the Istio Gateway and VirtualService resources specify. Run the following curl command to send the request:

    $ oc exec $CURL_POD -n curl -- \
      curl -s -I \
        -H Host:httpbin.example.com \
        <gateway_name>.<gateway_namespace>.svc.cluster.local/headers

12. The response should have a 200 OK HTTP status indicating that the request was successful.

    Example output

    HTTP/1.1 200 OK
    server: istio-envoy
    ...

13. Send a curl request to an endpoint that does not have a corresponding URI prefix match defined in the httpbin VirtualService by running the following command:

    $ oc exec $CURL_POD -n curl -- \
      curl -s -I \
        -H Host:httpbin.example.com \
        <gateway_name>.<gateway_namespace>.svc.cluster.local/get

    The response should return a 404 Not Found status. This is expected because the /get endpoint does not have a matching URI prefix in the httpbin VirtualService resource.

    Example output

    HTTP/1.1 404 Not Found
    server: istio-envoy
    ...

14. Expose the gateway proxy to traffic outside the cluster by setting the Service type to LoadBalancer:

    $ oc patch service <gateway_name> -n <gateway_namespace> -p '{"spec": {"type": "LoadBalancer"}}'

    Note

    A gateway can also be exposed to traffic outside the cluster by using OpenShift Routes. For more information, see "Exposing a gateway to traffic outside the cluster using OpenShift Routes".

15. Verify that httpbin service can be accessed from outside the cluster when using the external hostname or IP address of the gateway Service resource. Ensure that you set the INGRESS_HOST variable appropriately for the environment that your cluster is running in.

    1. If the cluster runs on AWS, set the INGRESS_HOST variable by running the following command:

       $ INGRESS_HOST=$(oc get service <gateway_name> -n <gateway_namespace> -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')

    2. If the cluster runs on GCP or Azure, set the INGRESS_HOST variable by running the following command:

       $ INGRESS_HOST=$(oc get service <gateway_name> -n <gateway_namespace> -o jsonpath='{.status.loadBalancer.ingress[0].ip}')

    3. Send a curl request to the httpbin service using the host of the gateway by running the following command:

       $ curl -s -I -H Host:httpbin.example.com http://$INGRESS_HOST/headers

16. Verify that the response has the HTTP/1.1 200 OK status, which indicates that the request was successful.

Procedure

1. Ensure that the Service type is set to ClusterIP by running the following command:

   $ oc patch service  -n  -p '{"spec": {"type": "ClusterIP"}}'

2. Create a YAML file named httpbin-route.yaml that defines a Route for the httpbin service.

   apiVersion: route.openshift.io/v1
   kind: Route
   metadata:
     name: httpbin
     namespace: <gateway_namespace>
   spec:
     host: httpbin.example.com
     port:
       targetPort: http2
     to:
       kind: Service
       name: <gateway_name>
       weight: 100
     wildcardPolicy: None

3. Apply the YAML file by running the following command:

   $ oc apply -f httpbin-route.yaml

4. Verify that httpbin service can be accessed from outside the cluster through the ingress router. Ensure that you set the INGRESS_HOST variable appropriately for the environment that your cluster is running in.

   1. If the cluster runs on AWS, set the INGRESS_HOST variable by running the following command:

      $ INGRESS_HOST=$(oc get service router-default -n openshift-ingress -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')

   2. If the cluster runs on GCP or Azure, set the INGRESS_HOST variable by running the following command:

      $ INGRESS_HOST=$(oc get service router-default -n openshift-ingress -o jsonpath='{.status.loadBalancer.ingress[0].ip}')

   3. Send a curl request to the httpbin service using the host of the ingress router by running the following command:

      $ curl -s -I -H Host:httpbin.example.com http://$INGRESS_HOST/headers

5. Verify that the response has the HTTP/1.1 200 OK status, which indicates that the request was successful.