OpenShift Service Mesh 3.0 is a Technology Preview feature only
Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. This documentation is a work in progress and might not be complete or fully tested.Chapter 1. Installing OpenShift Service Mesh
Installing OpenShift Service Mesh consists of three main tasks: installing the OpenShift Operator, deploying Istio, and customizing the Istio configuration. Then, you can also choose to install the sample bookinfo
application to push data through the mesh and explore mesh functionality.
1.1. About deploying Istio using the Red Hat OpenShift Service Mesh Operator
To deploy Istio using the Red Hat OpenShift Service Mesh Operator, you must create an Istio
resource. Then, the Operator creates an IstioRevision
resource, which represents one revision of the Istio control plane. Based on the IstioRevision
resource, the Operator deploys the Istio control plane, which includes the istiod
Deployment
resource and other resources.
The Red Hat OpenShift Service Mesh Operator may create additional instances of the IstioRevision
resource, depending on the update strategy defined in the Istio
resource.
1.1.1. About update strategies
The update strategy affects how the update process is performed. For each mesh, you select one of two strategies:
-
InPlace
-
RevisionBased
The default strategy is the InPlace
strategy. For more information, see the following documentation located in "Updating OpenShift Service Mesh":
- "About InPlace strategy"
- "About RevisionBased strategy"
1.2. Installing the Service Mesh Operator
Prerequisites
You have deployed a cluster on OpenShift Container Platform 4.14 or later.
You are logged in to the OpenShift Container Platform web console as a user with the cluster-admin role.
Procedure
-
In the OpenShift Container Platform web console, navigate to the Operators
OperatorHub page. - Search for the Red Hat OpenShift Service Mesh 3 Operator.
- Locate the Service Mesh Operator, and click to select it.
- When the prompt that discusses the community operator appears, click Continue.
- Verify the Service Mesh Operator is version 3.0, and click Install.
- Use the default installation settings presented, and click Install to continue.
-
Click Operators
Installed Operators to verify that the Service Mesh Operator is installed. Succeeded
should appear in the Status column.
1.3. About Istio deployment
To deploy Istio, you must create two resources: Istio
and IstioCNI
. The Istio
resource deploys and configures the Istio Control Plane. The IstioCNI
resource deploys and configures the Istio Container Network Interface (CNI) plugin. You should create these resources in separate projects; therefore, you must create two projects as part of the Istio deployment process.
You can use the OpenShift web console or the OpenShift CLI (oc) to create a project or a resource in your cluster.
In the OpenShift Container Platform, a project is essentially a Kubernetes namespace with additional annotations, such as the range of user IDs that can be used in the project. Typically, the OpenShift Container Platform web console uses the term project, and the CLI uses the term namespace, but the terms are essentially synonymous.
1.3.1. Creating the Istio project using the web console
The Service Mesh Operator deploys the Istio control plane to a project that you create. In this example, istio-system
is the name of the project.
Prerequisties
- The Red Hat OpenShift Service Mesh Operator must be installed.
- You are logged in to the OpenShift Container Platform web console as cluster-admin.
Procedure
-
In the OpenShift Container Platform web console, click Home
Projects. - Click Create Project.
-
At the prompt, enter a name for the project in the Name field. For example,
istio-system
. The other fields provide supplementary information to theIstio
resource definition and are optional. - Click Create. The Service Mesh Operator deploys Istio to the project you specified.
1.3.2. Creating the Istio resource using the web console
Create the Istio resource that will contain the YAML configuration file for your Istio deployment. The Red Hat OpenShift Service Mesh Operator uses information in the YAML file to create an instance of the Istio control plane.
Prerequisties
- The Service Mesh Operator must be installed.
- You are logged in to the OpenShift Container Platform web console as cluster-admin.
Procedure
-
In the OpenShift Container Platform web console, click Operators
Installed Operators. -
Select
istio-system
in the Project drop-down menu. - Click the Service Mesh Operator.
- Click Istio.
- Click Create Istio.
-
Select the
istio-system
project from the Namespace drop-down menu. Click Create. This action deploys the Istio control plane.
When
State: Healthy
appears in the Status column, Istio is successfully deployed.
1.3.3. Creating the IstioCNI project using the web console
The Service Mesh Operator deploys the Istio CNI plugin to a project that you create. In this example, istio-cni
is the name of the project.
Prerequisties
- The Red Hat OpenShift Service Mesh Operator must be installed.
- You are logged in to the OpenShift Container Platform web console as cluster-admin.
Procedure
-
In the OpenShift Container Platform web console, click Home
Projects. - Click Create Project.
-
At the prompt, you must enter a name for the project in the Name field. For example,
istio-cni
. The other fields provide supplementary information and are optional. - Click Create.
1.3.4. Creating the IstioCNI resource using the web console
Create an Istio Container Network Interface (CNI) resource, which contains the configuration file for the Istio CNI plugin. The Service Mesh Operator uses the configuration specified by this resource to deploy the CNI pod.
Prerequisties
- The Red Hat OpenShift Service Mesh Operator must be installed.
- You are logged in to the OpenShift Container Platform web console as cluster-admin.
Procedure
-
In the OpenShift Container Platform web console, click Operators
Installed Operators. -
Select
istio-cni
in the Project drop-down menu. - Click the Service Mesh Operator.
- Click IstioCNI.
- Click Create IstioCNI.
-
Ensure that the name is
default
. Click Create. This action deploys the Istio CNI plugin.
When
State: Healthy
appears in the Status column, the Istio CNI plugin is successfully deployed.
1.4. Scoping the Service Mesh with discovery selectors
Service Mesh includes workloads that meet the following criteria:
- The control plane has discovered the workload.
- The workload has an Envoy proxy sidecar injected.
By default, the control plane discovers workloads in all namespaces across the cluster, with the following results:
- Each proxy instance receives configuration for all namespaces, including workloads not enrolled in the mesh.
- Any workload with the appropriate pod or namespace injection label receives a proxy sidecar.
In shared clusters, you might want to limit the scope of Service Mesh to only certain namespaces. This approach is especially useful if multiple service meshes run in the same cluster.
1.4.1. About discovery selectors
With discovery selectors, the mesh administrator can control which namespaces the control plane can access. By using a Kubernetes label selector, the administrator sets the criteria for the namespaces visible to the control plane, excluding any namespaces that do not match the specified criteria.
Istiod always opens a watch to OpenShift for all namespaces. However, discovery selectors ignore objects that are not selected very early in its processing, minimizing costs.
The discoverySelectors
field accepts an array of Kubernetes selectors, which apply to labels on namespaces. You can configure each selector for different use cases:
-
Custom label names and values. For example, configure all namespaces with the label
istio-discovery=enabled
. -
A list of namespace labels by using set-based selectors with OR logic. For instance, configure namespaces with
istio-discovery=enabled
ORregion=us-east1
. -
Inclusion and exclusion of namespaces. For example, configure namespaces with
istio-discovery=enabled
AND the labelapp=helloworld
.
Discovery selectors are not a security boundary. Istiod continues to have access to all namespaces even when you have configured the discoverySelector
field.
Additional resources
1.4.2. Scoping a Service Mesh by using discovery selectors
If you know which namespaces to include in the Service Mesh, configure discoverySelectors
during or after installation by adding the required selectors to the meshConfig.discoverySelectors
section of the Istio
resource. For example, configure Istio to discover only namespaces labeled istio-discovery=enabled
.
Prerequisites
- The OpenShift Service Mesh operator is installed.
- An Istio CNI resource is created.
Procedure
Add a label to the namespace containing the Istio control plane, for example, the
istio-system
system namespace.$ oc label namespace istio-system istio-discovery=enabled
Modify the
Istio
control plane resource to include adiscoverySelectors
section with the same label.kind: Istio apiVersion: sailoperator.io/v1alpha1 metadata: name: default spec: namespace: istio-system values: meshConfig: discoverySelectors: - matchLabels: istio-discovery: enabled
Apply the Istio CR:
$ oc apply -f istio.yaml
-
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.
Discovery selectors help restrict the scope of a single Service Mesh and are essential for limiting the control plane scope when you deploy multiple Istio control planes in a single cluster.
1.5. About the Bookinfo application
Installing the bookinfo
example application consists of two main tasks: deploying the application and creating a gateway so the application is accessible outside the cluster.
You can use the bookinfo
application to explore service mesh features. Using the bookinfo
application, you can easily confirm that requests from a web browser pass through the mesh and reach the application.
The bookinfo
application displays information about a book, similar to a single catalog entry of an online book store. The application displays a page that describes the book, lists book details (ISBN, number of pages, and other information), and book reviews.
The bookinfo
application is exposed through the mesh, and the mesh configuration determines how the microservices comprising the application are used to serve requests. The review information comes from one of three services: reviews-v1
, reviews-v2
or reviews-v3
. If you deploy the bookinfo
application without defining the reviews
virtual service, then the mesh uses a round robin rule to route requests to a service.
By deploying the reviews
virtual service, you can specify a different behavior. For example, you can specify that if a user logs into the bookinfo
application, then the mesh routes requests to the reviews-v2
service, and the application displays reviews with black stars. If a user does not log into the bookinfo
application, then the mesh routes requests to the reviews-v3
service, and the application displays reviews with red stars.
For more information, see Bookinfo Application in the upstream Istio documentation.
1.5.1. Deploying the Bookinfo application
Prerequisites
- You have deployed a cluster on OpenShift Container Platform 4.15 or later.
-
You are logged in to the OpenShift Container Platform web console as a user with the
cluster-admin
role. - You have access to the OpenShift CLI (oc).
- You have installed the Red Hat OpenShift Service Mesh Operator, created the Istio resource, and the Operator has deployed Istio.
- You have created IstioCNI resource, and the Operator has deployed the necessary IstioCNI pods.
Procedure
-
In the OpenShift Container Platform web console, navigate to the Home
Projects page. - Click Create Project.
Enter
bookinfo
in the Project name field.The Display name and Description fields provide supplementary information and are not required.
- Click Create.
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
NoteIn this example, the name of the Istio resource is
default
. If the Istio resource name is different, you must set theistio.io/rev
label to the name of the Istio resource instead of adding theistio-injection=enabled
label.Apply the
bookinfo
YAML file to deploy thebookinfo
application by entering the following command:oc apply -f https://raw.githubusercontent.com/istio/istio/release-1.23/samples/bookinfo/platform/kube/bookinfo.yaml -n bookinfo
Verification
Verify that the
bookinfo
service is available by running the following command:$ oc get services -n bookinfo
Example output
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
Verify that the
bookinfo
pods are available by running the following command:$ oc get pods -n bookinfo
Example output
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 displays2/2
, the proxy sidecar was successfully injected. Confirm thatRunning
appears in theStatus
column for each pod.Verify that the
bookinfo
application is running by sending a request to thebookinfo
page. Run the following command:$ oc exec "$(oc get pod -l app=ratings -n bookinfo -o jsonpath='{.items[0].metadata.name}')" -c ratings -n bookinfo -- curl -sS productpage:9080/productpage | grep -o "<title>.*</title>"
1.5.2. About accessing the Bookinfo application using a gateway
The Red Hat OpenShift Service Mesh Operator does not deploy gateways. Gateways are not part of the control plane. As a security best-practice, Ingress and Egress gateways should be deployed in a different namespace than the namespace that contains the control plane.
You can deploy gateways using either the Gateway API or the gateway injection method.
1.5.3. Accessing the Bookinfo application by using Istio gateway injection
Gateway injection uses the same mechanisms as Istio sidecar injection to create a gateway from a Deployment
resource that is paired with a Service
resource. The Service
resource can be made accessible from outside an OpenShift Container Platform cluster.
Prerequisties
-
You are logged in to the OpenShift Container Platform web console as
cluster-admin
. - The Red Hat OpenShift Service Mesh Operator must be installed.
- The Istio resource must be deployed.
Procedure
Create the
istio-ingressgateway
deployment and service by running the following command at the CLI:$ oc apply -n bookinfo -f ingress-gateway.yaml
NoteThis example uses a sample
ingress-gateway.yaml
file that is available in the Istio community repository.Configure the
bookinfo
application to use the new gateway by applying the gateway configuration:$ oc apply -f https://raw.githubusercontent.com/istio/istio/release-1.23/samples/bookinfo/networking/bookinfo-gateway.yaml -n bookinfo
NoteTo configure gateway injection with the
bookinfo
application, this example uses a sample gateway configuration file that must be applied in the namespace where the application is installed.Use a route to expose the gateway external to the cluster:
$ oc expose service istio-ingressgateway -n bookinfo
Automatically scale the pod when ingress traffic increases. This example sets the minimum replicas to
2
and the maximum replicas to5
. It also creates another replica when utilization reaches 80%.apiVersion: autoscaling/v2 kind: HorizontalPodAutoscaler metadata: labels: istio: ingressgateway release: istio name: ingressgatewayhpa namespace: istio-ingress 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
Specify the minimum number of pods that must be running on the node. This example ensures one replica is running if a pod gets restarted on a new node.
apiVersion: policy/v1 kind: PodDisruptionBudget metadata: labels: istio: ingressgateway release: istio name: ingressgatewaypdb namespace: istio-ingress spec: minAvailable: 1 selector: matchLabels: istio: ingressgateway
Obtain the gateway host name and the URL for the product page:
$ HOST=$(oc get route istio-ingressgateway -n bookinfo -o jsonpath='{.spec.host}') $ echo productpage URL: http://$HOST/productpage
-
Verify that the
productpage
is accessible from a web browser.
1.5.4. Accessing the Bookinfo application by using Gateway API
The Kubernetes Gateway API deploys a gateway by creating a Gateway
resource. In OpenShift Container Platform 4.15 and later versions. If you want your cluster to use the Gateway API CRDs, you must enable the CRDs because they are disabled by default.
Red Hat provides support for using the Kubernetes Gateway API with Red Hat OpenShift Service Mesh. Red Hat does not provide support for the Kubernetes Gateway API custom resource definitions (CRDs). In this procedure, the use of community Gateway API CRDs is shown for demonstration purposes only.
Prerequisites
-
You are logged in to the OpenShift Container Platform web console as
cluster-admin
. - The Red Hat OpenShift Service Mesh Operator must be installed.
- The Istio resource must be deployed.
-
You are logged in to the OpenShift Container Platform web console as
Procedure
Enable the Gateway API CRDs:
$ 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 -; }
Create and configure a gateway using a
Gateway
resource andHTTPRoute
resource:$ oc apply -f https://raw.githubusercontent.com/istio/istio/release-1.23/samples/bookinfo/gateway-api/bookinfo-gateway.yaml -n bookinfo
NoteTo configure a gateway with the
bookinfo
application by using the Gateway API, this example uses a sample gateway configuration file that must be applied in the namespace where the application is installed.Ensure that the Gateway API service is ready, and has an address allocated:
$ oc wait --for=condition=programmed gtw bookinfo-gateway -n bookinfo
Retrieve the host, port and gateway URL:
$ export INGRESS_HOST=$(oc get gtw bookinfo-gateway -n bookinfo -o jsonpath='{.status.addresses[0].value}') $ export INGRESS_PORT=$(oc get gtw bookinfo-gateway -n bookinfo -o jsonpath='{.spec.listeners[?(@.name=="http")].port}') $ export GATEWAY_URL=$INGRESS_HOST:$INGRESS_PORT
Obtain the gateway host name and the URL of the product page:
$ echo "http://${GATEWAY_URL}/productpage"
-
Verify that the
productpage
is accessible from a web browser.
1.6. Customizing Istio configuration
The values
field of the Istio
custom resource definition, which was created when the control plane was deployed, can be used to customize Istio configuration using Istio’s Helm
configuration values. When you create this resource using the OpenShift Container Platform web console, it is pre-populated with configuration settings to enable Istio to run on OpenShift.
Procedure
-
Click Operators
Installed Operators. - Click Istio in the Provided APIs column.
-
Click the
Istio
instance, nameddefault
, in the Name column. -
Click YAML to view the
Istio
configuration and make modifications.
For a list of available configuration for the values
field, refer to Istio’s artifacthub chart documentation.
Additional resources