Chapter 2. Installing OpenShift Service Mesh

Procedure

1. In the OpenShift Container Platform web console, click Home Projects.
2. Click Create Project.
3. At the prompt, enter a name for the project in the Name field. For example, istio-system. The other fields offer supplementary information to the Istio resource definition and are optional.
4. Click Create. The Service Mesh Operator deploys Istio to the project you specified.

Procedure

1. In the OpenShift Container Platform web console, click Operators Installed Operators.
2. Select istio-system in the Project drop-down menu.
3. Click the Service Mesh Operator.
4. Click Istio.
5. Click Create Istio.
6. Select the istio-system project from the Namespace drop-down menu.

7. Click Create. This action deploys the Istio control plane.

   When State: Healthy displays in the Status column, Istio is successfully deployed.

Procedure

1. In the OpenShift Container Platform web console, click Home Projects.
2. Click Create Project.
3. At the prompt, you must enter a name for the project in the Name field. For example, istio-cni. The other fields offer supplementary information and are optional.
4. Click Create.

Procedure

1. In the OpenShift Container Platform web console, click Operators Installed Operators.
2. Select istio-cni in the Project drop-down menu.
3. Click the Service Mesh Operator.
4. Click IstioCNI.
5. Click Create IstioCNI.
6. Ensure that the name is default.

7. Click Create. This action deploys the Istio CNI plugin.

   When State: Healthy displays in the Status column, the Istio CNI plugin is successfully deployed.

Procedure

1. Add a label to the namespace containing the Istio control plane, for example, the istio-system system namespace, by running the following command:

   $ oc label namespace istio-system istio-discovery=enabled

2. Change the Istio control plane resource to include a discoverySelectors section with the same label, similar to the following example:

   kind: Istio
   apiVersion: sailoperator.io/v1
   metadata:
     name: default
   spec:
     namespace: istio-system
     values:
       meshConfig:
         discoverySelectors:
           - matchLabels:
               istio-discovery: enabled

3. Apply the Istio custom resource (CR) by running the following command:

   $ oc apply -f istio.yaml

4. Ensure that all namespaces that will contain workloads that are to be part of the Service Mesh have both the discoverySelector label and, if needed, the appropriate Istio injection label.

   Note

   Discovery selectors help restrict the scope of a single Service Mesh and are essential for limiting the control plane scope when you deploy many Istio control planes in a single cluster.

Procedure

1. In the OpenShift Container Platform web console, navigate to the Home Projects page.
2. Click Create Project.

3. Enter bookinfo in the Project name field.

   The Display name and Description fields offer supplementary information and are not required.

4. Click Create.

5. Apply the Istio discovery selector and injection label to the bookinfo namespace by entering the following command:

   $ oc label namespace bookinfo istio-discovery=enabled istio-injection=enabled

   Note

   In this example, the name of the Istio resource is default. If the Istio resource name is different, you must set the istio.io/rev label to the name of the Istio resource instead of adding the istio-injection=enabled label.

6. Apply the bookinfo YAML file to deploy the bookinfo application by entering the following command:

   oc apply -f https://raw.githubusercontent.com/openshift-service-mesh/istio/release-1.24/samples/bookinfo/platform/kube/bookinfo.yaml -n bookinfo

Verification

1. Verify that the bookinfo service is available by running the following command:

   $ oc get services -n bookinfo

   You should see output similar to the following example:

   NAME          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
   details       ClusterIP   172.30.137.21   <none>        9080/TCP   44s
   productpage   ClusterIP   172.30.2.246    <none>        9080/TCP   43s
   ratings       ClusterIP   172.30.33.85    <none>        9080/TCP   44s
   reviews       ClusterIP   172.30.175.88   <none>        9080/TCP   44s

2. Verify that the bookinfo pods are available by running the following command:

   $ oc get pods -n bookinfo

   You should see output similar to the following example:

   NAME                             READY   STATUS    RESTARTS   AGE
   details-v1-698d88b-km2jg         2/2     Running   0          66s
   productpage-v1-675fc69cf-cvxv9   2/2     Running   0          65s
   ratings-v1-6484c4d9bb-tpx7d      2/2     Running   0          65s
   reviews-v1-5b5d6494f4-wsrwp      2/2     Running   0          65s
   reviews-v2-5b667bcbf8-4lsfd      2/2     Running   0          65s
   reviews-v3-5b9bd44f4-44hr6       2/2     Running   0          65s

   When the Ready columns displays 2/2, the proxy sidecar was successfully injected. Confirm that Running displays in the Status column for each pod.

3. Verify that the bookinfo application is running by sending a request to the bookinfo page. Run the following command:

   $ oc exec "$(oc get pod -l app=ratings -n bookinfo -o jsonpath='{.items[0].metadata.name}')" -c ratings -n bookinfo -- curl -sS productpage:9080/productpage | grep -o "<title>.*</title>"

Procedure

1. Create the istio-ingressgateway deployment and service by running the following command:

   $ oc apply -n bookinfo -f ingress-gateway.yaml

   Note

   This example uses a sample ingress-gateway.yaml file that is available in the Istio community repository.

2. Configure the bookinfo application to use the new gateway. Apply the gateway configuration by running the following command:

   $ oc apply -f https://raw.githubusercontent.com/openshift-service-mesh/istio/release-1.24/samples/bookinfo/networking/bookinfo-gateway.yaml -n bookinfo

   Note

   To configure gateway injection with the bookinfo application, this example provides a sample gateway configuration file that you must apply in the application’s namespace.

3. Use a route to expose the gateway external to the cluster by running the following command:

   $ oc expose service istio-ingressgateway -n bookinfo

4. Change the YAML file to automatically scale the pod when ingress traffic increases.

   You can see the following example configuration for reference:

   apiVersion: autoscaling/v2
   kind: HorizontalPodAutoscaler
   metadata:
     labels:
       istio: ingressgateway
       release: istio
     name: ingressgatewayhpa
     namespace: bookinfo
   spec:
     maxReplicas: 5
     metrics:
     - resource:
         name: cpu
         target:
           averageUtilization: 80
           type: Utilization
       type: Resource
     minReplicas: 2
     scaleTargetRef:
       apiVersion: apps/v1
       kind: Deployment
       name: istio-ingressgateway

   • spec.maxReplicas shows an example that sets the maximum replicas to 5 and the minimum replicas to 2. It also creates another replica when usage reaches 80%.

5. Specify the minimum number of pods that must be running on the node.

   You can see the following example configuration for reference:

   apiVersion: policy/v1
   kind: PodDisruptionBudget
   metadata:
     labels:
       istio: ingressgateway
       release: istio
     name: ingressgatewaypdb
     namespace: bookinfo
   spec:
     minAvailable: 1
     selector:
       matchLabels:
         istio: ingressgateway

   spec.minAvailable shows an example that ensures one replica is running if a pod gets restarted on a new node.

6. Obtain the gateway hostname and the URL for the product page by running the following command:

   $ HOST=$(oc get route istio-ingressgateway -n bookinfo -o jsonpath='{.spec.host}')

7. Verify that the productpage is accessible from a web browser by running the following command:

   $ echo productpage URL: http://$HOST/productpage

Procedure

1. Enable the Gateway API CRDs for OpenShift Container Platform 4.18 and earlier, by running the following command:

   $ oc get crd gateways.gateway.networking.k8s.io &> /dev/null ||  { oc kustomize "github.com/kubernetes-sigs/gateway-api/config/crd?ref=v1.0.0" | oc apply -f -; }

2. Create and configure a gateway by using the Gateway and HTTPRoute resources by running the following command:

   $ oc apply -f https://raw.githubusercontent.com/openshift-service-mesh/istio/release-1.24/samples/bookinfo/gateway-api/bookinfo-gateway.yaml -n bookinfo

   Note

   To configure a gateway with the bookinfo application by using the Gateway API, this example provides a sample gateway configuration file that you must apply to the application’s namespace.

3. Ensure that the Gateway API service is ready, and has an address allocated by running the following command:

   $ oc wait --for=condition=programmed gtw bookinfo-gateway -n bookinfo

4. Retrieve the host by running the following command:

   $ export INGRESS_HOST=$(oc get gtw bookinfo-gateway -n bookinfo -o jsonpath='{.status.addresses[0].value}')

5. Retrieve the port by running the following command:

   $ export INGRESS_PORT=$(oc get gtw bookinfo-gateway -n bookinfo -o jsonpath='{.spec.listeners[?(@.name=="http")].port}')

6. Retrieve the gateway URL by running the following command:

   $ export GATEWAY_URL=$INGRESS_HOST:$INGRESS_PORT

7. Obtain the gateway hostname and the URL of the product page by running the following command:

   $ echo "http://${GATEWAY_URL}/productpage"

Procedure

1. In the OpenShift Container Platform web console, click Installed Operators.
2. Click Red Hat OpenShift Service Mesh 3 Operator.
3. Click Istio.
4. Click the name of the Istio installation. For example, default.
5. Click YAML.

6. Change the Istio custom resource (CR) similar to the following example:

   apiVersion: sailoperator.io/v1
   kind: Istio
   metadata:
     name: default
   spec:
     namespace: istio-system
     values:
       pilot:
         autoscaleMin: 2
         autoscaleMax: 5
         cpu:
           targetAverageUtilization: 80
         memory:
           targetAverageUtilization: 80

   • spec.values.pilot.autoscaleMin specifies the minimum number of Istio control plane replicas that always run.
   • spec.values.pilot.autoscaleMax specifies the maximum number of Istio control plane replicas, allowing for scaling based on load. To support HA, there must be at least two replicas.
   • spec.values.pilot.cpu.targetAverageUtilization specifies the target CPU usage for autoscaling to 80%. If the average CPU usage exceeds this threshold, the Horizontal Pod Autoscaler (HPA) automatically increases the number of replicas.
   • spec.values.pilot.memory.targetAverageUtilization specifies the target memory usage for autoscaling to 80%. If the average memory usage exceeds this threshold, the HPA automatically increases the number of replicas.

Procedure

1. Obtain the name of the Istio resource by running the following command:

   $ oc get istio -n istio-sytem

   You should see output similar to the following example:

   NAME      REVISIONS   READY   IN USE   ACTIVE REVISION   STATUS    VERSION   AGE
   default   1           1       0        default           Healthy   v1.24.6   24m

   The name of the Istio resource is default.

2. Update the Istio custom resource (CR) by adding the autoscaleEnabled and replicaCount parameters by running the following command:

   $ oc patch istio default -n istio-system --type merge -p '
   spec:
     values:
       pilot:
         autoscaleEnabled: false
         replicaCount: 2
   '

   • spec.values.pilot.autoscaleEnabled specifies a setting that disables autoscaling and ensures that the number of replicas remains fixed.
   • spec.values.pilot.replicaCount specifies the number of Istio control plane replicas. To support HA, there must be at least two replicas.

Verification

1. Verify the status of the Istio control pods by running the following command:

   $ oc get pods -n istio-system -l app=istiod

   You should see output similar to the following example:

   NAME                      READY   STATUS    RESTARTS   AGE
   istiod-7c7b6564c9-nwhsg   1/1     Running   0          70s
   istiod-7c7b6564c9-xkmsl   1/1     Running   0          85s

   Two istiod pods are running, which is the minimum requirement for an HA Istio control plane and indicates that a basic HA setup is in place.