Gloo Operator

Overview link

In this guide, you deploy a sidecar mesh to each workload cluster, create an east-west gateway in each cluster, and link the istiod control planes across cluster networks by using peering gateways. In the next guide, you can deploy the Bookinfo sample app to the sidecar mesh in each cluster, and make select services available across the multicluster mesh. Incoming requests can then be routed from an ingress gateway, such as Gloo Gateway, to services in your mesh across all clusters.

The following diagram demonstrates a service mesh setup across multiple clusters.

Considerations link

Before you install a multicluster sidecar mesh, review the following considerations and requirements.

License requirements link

Version requirements link

Review the following known Istio version requirements and restrictions.

• Patch versions 1.26.0 and 1.26.1 of the Solo distribution of Istio lack support for FIPS-tagged images and ztunnel outlier detection. When upgrading or installing 1.26, be sure to use patch version 1.26.1-patch0 and later only.
• In the Solo distribution of Istio 1.25 and later, you can access enterprise-level features by passing your Solo license in the license.value or license.secretRef field of the Solo distribution of the istiod Helm chart. The Solo istiod Helm chart is strongly recommended due to the included safeguards, default settings, and upgrade handling to ensure a reliable and secure Istio deployment. Though it is not recommended, you can pass your license key in the open source istiod Helm chart by using the --set pilot.env.SOLO_LICENSE_KEY field.
• Multicluster setups require the Solo distribution of Istio version 1.24.3 or later (1.24.3-solo), including the Solo distribution of istioctl.
• Due to a lack of support for the Istio CNI and iptables for the Istio proxy, you cannot run Istio (and therefore Gloo Mesh (OSS APIs)) on AWS Fargate. For more information, see the Amazon EKS issue.

Components link

In the following steps, you install the Istio ambient components in each workload cluster to successfully create east-west gateways and establish multicluster peering, even if you plan to use a sidecar mesh. However, sidecar mesh setups continue to use sidecar injection for your workloads. Your workloads are not added to an ambient mesh. For more information about running both ambient and sidecar components in one mesh setup, see Ambient-sidecar interoperability.

Revision and canary upgrade limitations link

The upgrade guides in this documentation show you how to perform in-place upgrades for your Istio components, which is the recommended upgrade strategy.

Cross-cluster traffic addresses link

In each cluster, you create an east-west gateway, which is implemented as a ztunnel that facilitates traffic between services across clusters in your multicluster mesh. In the Solo distribution of Istio 1.28 and later, you can use either LoadBalancer or NodePort addresses to resolve cross-cluster traffic requests through this gateway. Note that the NodePort method is considered alpha in Istio version 1.28.

LoadBalancer: In the standard LoadBalancer peering method, cross-cluster traffic through the east-west gateway resolves to its LoadBalancer address.

NodePort (alpha): If you prefer to use direct pod-to-pod traffic across clusters, you can annotate the east-west and peering gateways so that cross-cluster traffic resolves to NodePort addresses. This method allows you to avoid LoadBalancer services to reduce cross-cluster traffic costs. Review the following considerations:

• Note that the gateways must still be created with stable IP addresses, which are required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data-plane communication, in that requests to services resolve to the NodePort instead of the LoadBalancer address. Also, the east-west gateway must have the topology.istio.io/cluster label.
• If a node in a target cluster becomes inaccessible, such as during a restart or replacement, a delay can occur in the connection from the client cluster that must become aware of the new east-west gateway NodePort. In this case, you might see a connection error when trying to send cross-cluster traffic to an east-west gateway that is no longer accepting connections.
• Only nodes where an east-west gateway pod is provisioned are considered targets for traffic.
• Like LoadBalancer gateways, NodePort gateways support traffic from Envoy-based ingress gateways, waypoints, and sidecars.
• This feature is in an alpha state. Alpha features are likely to change, are not fully tested, and are not supported for production. For more information, see Solo feature maturity.

The steps in the following guide to create the gateways include options for either the LoadBalancer or NodePort method. A status condition on each east-west and remote peer gateway indicates which dataplane service type is in use.

Migrating from multicluster community Istio link

If you previously used the multicluster feature in community Istio, and want to now migrate to multicluster peering in the Solo distribution of Istio, the DISABLE_LEGACY_MULTICLUSTER environment variable is introduced in the Solo distribution of Istio version 1.28 to disable the community multicluster mechanisms. Multicluster in community Istio uses remote secrets that contain kubeconfigs to watch resources on remote clusters. This system is incompatible with the decentralized, push-based model for peering in the Solo distribution of Istio. This variable causes istiod to ignore remote secrets so that it does not attempt to set up Kubernetes clients to connect to them.

• For fresh multicluster mesh installations with the Solo distribution of Istio, use this environment variable in your istiod settings. This setting serves as a recommended safety measure to prevent any use of remote secrets.
• If you want to initiate a multicluster migration from community Istio, contact a Solo account representative. An account representative can help you set up two revisions of Istio that each select a different set of namespaces, and set the DISABLE_LEGACY_MULTICLUSTER variable on the revision that uses the Solo distribution of Istio for multicluster peering.

Set up tools link

1. Save the following environment details and install the Solo distribution of the istioctl binary.

   1. Set your Enterprise level license for Gloo Mesh as an environment variable. If you do not have one, contact an account representative. If you prefer to specify license keys in a secret instead, see Licensing.

           export GLOO_MESH_LICENSE_KEY=<enterprise_license_key>
           

   2. Choose the version of Istio that you want to install or upgrade to by reviewing the supported versions.

   3. Save the Solo distribution of Istio version.

           export ISTIO_VERSION=1.28.1-patch0
         export ISTIO_IMAGE=${ISTIO_VERSION}-solo
           

   4. Save the image and Helm repository information for the Solo distribution of Istio.

      • Istio 1.29 and later:

             export REPO=us-docker.pkg.dev/soloio-img/istio
           export HELM_REPO=us-docker.pkg.dev/soloio-img/istio-helm
             

      • Istio 1.28 and earlier: You must provide a repo key for the minor version of the Solo distribution of Istio that you want to install. This is the 12-character hash at the end of the repo URL us-docker.pkg.dev/gloo-mesh/istio-<repo-key>, which you can find in the Istio images built by Solo.io support article.

             # 12-character hash at the end of the repo URL
           export REPO_KEY=<repo_key>
           export REPO=us-docker.pkg.dev/gloo-mesh/istio-${REPO_KEY}
           export HELM_REPO=us-docker.pkg.dev/gloo-mesh/istio-helm-${REPO_KEY}
             

   5. Get the Solo distribution of Istio binary and install istioctl, which you use for multicluster linking and gateway commands.

      1. Get the OS and architecture that you use on your machine.

              OS=$(uname | tr '[:upper:]' '[:lower:]' | sed -E 's/darwin/osx/')
            ARCH=$(uname -m | sed -E 's/aarch/arm/; s/x86_64/amd64/; s/armv7l/armv7/')
            echo $OS
            echo $ARCH
              

      2. Download the Solo distribution of Istio binary and install istioctl.

         • Istio 1.29 and later:

                mkdir -p ~/.istioctl/bin
              curl -sSL https://storage.googleapis.com/soloio-istio-binaries/release/$ISTIO_IMAGE/istio-$ISTIO_IMAGE-$OS-$ARCH.tar.gz | tar xzf - -C ~/.istioctl/bin
              mv ~/.istioctl/bin/istio-$ISTIO_IMAGE/bin/istioctl ~/.istioctl/bin/istioctl
              chmod +x ~/.istioctl/bin/istioctl
              
              export PATH=${HOME}/.istioctl/bin:${PATH}
                

         • Istio 1.28 and earlier:

                mkdir -p ~/.istioctl/bin
              curl -sSL https://storage.googleapis.com/istio-binaries-$REPO_KEY/$ISTIO_IMAGE/istioctl-$ISTIO_IMAGE-$OS-$ARCH.tar.gz | tar xzf - -C ~/.istioctl/bin
              chmod +x ~/.istioctl/bin/istioctl
              
              export PATH=${HOME}/.istioctl/bin:${PATH}
                

      3. Verify that the istioctl client runs the Solo distribution of Istio that you want to install.

              istioctl version --remote=false
              

         Example output:

              client version: 1.28.1-patch0-solo
              

2. Deploy Istio to each cluster and link clusters. These steps vary based on whether you want to manually link meshes across clusters or use Gloo Mesh to automatically link clusters. Note that automatic linking is a beta feature, and requires Istio to be installed in the same cluster that the Gloo management plane is deployed to.

Option 1: Manually link meshes link

In each cluster, use the Gloo Operator to create the service mesh components. Then, create an east-west gateway so that traffic requests can be routed cross-cluster, and link clusters to enable cross-cluster service discovery.

Create a shared root of trust link

Each cluster in the multicluster setup must have a shared root of trust. This can be achieved by providing a root certificate signed by a PKI provider, or a custom root certificate created for this purpose. The root certificate signs a unique intermediate CA certificate for each cluster.

  curl -L https://istio.io/downloadIstio | ISTIO_VERSION=${ISTIO_VERSION} sh -
cd istio-${ISTIO_VERSION}

mkdir -p certs
pushd certs
make -f ../tools/certs/Makefile.selfsigned.mk root-ca

function create_cacerts_secret() {
  context=${1:?context}
  cluster=${2:?cluster}
  make -f ../tools/certs/Makefile.selfsigned.mk ${cluster}-cacerts
  kubectl --context=${context} create ns istio-system || true
  kubectl --context=${context} create secret generic cacerts -n istio-system \
    --from-file=${cluster}/ca-cert.pem \
    --from-file=${cluster}/ca-key.pem \
    --from-file=${cluster}/root-cert.pem \
    --from-file=${cluster}/cert-chain.pem
}

create_cacerts_secret ${REMOTE_CONTEXT1} ${REMOTE_CLUSTER1}
create_cacerts_secret ${REMOTE_CONTEXT2} ${REMOTE_CLUSTER2}

cd ../..
  

Deploy mesh components link

1. Save the name and kubeconfig context of a cluster where you want to install Istio in the following environment variables. Each time you repeat the steps in this guide, you change these variables to the next workload cluster’s name and context.

     export CLUSTER_NAME=<cluster-name>
   export CLUSTER_CONTEXT=<cluster-context>
     

2. Install the Gloo Operator to the gloo-mesh namespace. This operator deploys and manages your Istio installation. For more information, see the Helm reference. Note that if you already installed Gloo Mesh, you can optionally reference the secret that Gloo Mesh (OSS APIs) automatically creates for your license in the –set manager.env.SOLO_ISTIO_LICENSE_KEY_SECRET_REF=gloo-mesh/license-keys flag instead.

     helm install gloo-operator oci://us-docker.pkg.dev/solo-public/gloo-operator-helm/gloo-operator \
     --version 0.4.2 \
     -n gloo-mesh \
     --create-namespace \
     --kube-context ${CLUSTER_CONTEXT} \
     --set manager.env.SOLO_ISTIO_LICENSE_KEY=${GLOO_MESH_LICENSE_KEY}
     

3. Verify that the operator pod is running.

     kubectl get pods -n gloo-mesh --context ${CLUSTER_CONTEXT} -l app.kubernetes.io/name=gloo-operator
     

   Example output:

     gloo-operator-78d58d5c7b-lzbr5     1/1     Running   0          48s
     

4. Create a ServiceMeshController custom resource to configure an Istio installation. For a description of each configurable field, see the ServiceMeshController reference. If you need to set more advanced Istio configuration, you can also create a gloo-extensions-config configmap.

     kubectl apply -n gloo-mesh --context ${CLUSTER_CONTEXT} -f -<<EOF
   apiVersion: operator.gloo.solo.io/v1
   kind: ServiceMeshController
   metadata:
     name: managed-istio
     labels:
       app.kubernetes.io/name: managed-istio
   spec:
     cluster: ${CLUSTER_NAME}
     network: ${CLUSTER_NAME}
     dataplaneMode: Ambient # required for multicluster setups
     installNamespace: istio-system
     version: ${ISTIO_VERSION}
   EOF
     

   info

   Note that the operator detects your cloud provider and cluster platform, and configures the necessary settings required for that platform for you. For example, if you create an ambient mesh in an OpenShift cluster, no OpenShift-specific settings are required in the ServiceMeshController, because the operator automatically sets the appropriate settings for OpenShift and your specific cloud provider accordingly.
   
   If you set the installNamespace to a namespace other than gloo-system, gloo-mesh, or istio-system, you must include the ‐‐set manager.env.WATCH_NAMESPACES=<namespace> setting.

5. Verify that the ServiceMeshController is ready. In the Status section of the output, make sure that all statuses are True, and that the phase is SUCCEEDED.

     kubectl describe servicemeshcontroller -n gloo-mesh managed-istio --context ${CLUSTER_CONTEXT}
     

   Example output:

     ...
   Status:
     Conditions:
       Last Transition Time:  2024-12-27T20:47:01Z
       Message:               Manifests initialized
       Observed Generation:   1
       Reason:                ManifestsInitialized
       Status:                True
       Type:                  Initialized
       Last Transition Time:  2024-12-27T20:47:02Z
       Message:               CRDs installed
       Observed Generation:   1
       Reason:                CRDInstalled
       Status:                True
       Type:                  CRDInstalled
       Last Transition Time:  2024-12-27T20:47:02Z
       Message:               Deployment succeeded
       Observed Generation:   1
       Reason:                DeploymentSucceeded
       Status:                True
       Type:                  ControlPlaneDeployed
       Last Transition Time:  2024-12-27T20:47:02Z
       Message:               Deployment succeeded
       Observed Generation:   1
       Reason:                DeploymentSucceeded
       Status:                True
       Type:                  CNIDeployed
       Last Transition Time:  2024-12-27T20:47:02Z
       Message:               Deployment succeeded
       Observed Generation:   1
       Reason:                DeploymentSucceeded
       Status:                True
       Type:                  WebhookDeployed
       Last Transition Time:  2024-12-27T20:47:02Z
       Message:               All conditions are met
       Observed Generation:   1
       Reason:                SystemReady
       Status:                True
       Type:                  Ready
     Phase:                   SUCCEEDED
   Events:                    <none>
     

6. Verify that the istiod control plane, Istio CNI, and ztunnel pods are running.

     kubectl get pods -n istio-system --context ${CLUSTER_CONTEXT}
     

   Example output:

     NAME                          READY   STATUS    RESTARTS   AGE
   istio-cni-node-6s5nk          1/1     Running   0          2m53s
   istio-cni-node-blpz4          1/1     Running   0          2m53s
   istiod-gloo-bb86b959f-msrg7   1/1     Running   0          2m45s
   istiod-gloo-bb86b959f-w29cm   1/1     Running   0          3m
   ztunnel-mx8nw                 1/1     Running   0          2m52s
   ztunnel-w8r6c                 1/1     Running   0          2m52s
     

7. Apply the CRDs for the Kubernetes Gateway API to your cluster, which are required to create components such as waypoint proxies for L7 traffic policies, gateways with the Gateway resource, and more.

     kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.4.0/standard-install.yaml --context ${CLUSTER_CONTEXT}
     

8. Create an east-west gateway in the istio-eastwest namespace. In each cluster, the east-west gateway is implemented as a ztunnel that facilitates traffic between services across clusters in your multicluster mesh. You can use either LoadBalancer or NodePort addresses for cross-cluster traffic.

   1. Create the istio-eastwest namespace.

        kubectl create namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   2. Use the following istioctl command to quickly create the east-west gateway. To take a look at the Gateway resource that this command creates, you can include the --generate flag in the command. Cross-cluster traffic though this gateway resolves to the LoadBalancer address.

        istioctl multicluster expose --namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   Note that the gateway must still be created with a stable IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address.

   1. Create the istio-eastwest namespace.

        kubectl create namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   2. Use the following istioctl command to quickly create the east-west gateway. To take a look at the Gateway resource that this command creates, you can include the --generate flag in the command. Note that the HBONE listener that is created by default on this gateway is unused, because traffic is routed through the NodePort directly.

        istioctl multicluster expose --namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   3. Annotate the gateway so that cross-cluster traffic through this gateway resolves to the NodePort address.

        kubectl annotate gateway istio-eastwest -n istio-eastwest peering.solo.io/data-plane-service-type=NodePort --context ${CLUSTER_CONTEXT}
        

9. Verify that the east-west gateway is successfully deployed.

     kubectl get pods -n istio-eastwest --context $CLUSTER_CONTEXT
     

10. For each cluster that you want to include in the multicluster mesh setup, repeat these steps to install the Gloo Operator, service mesh components, and east-west gateway in each cluster. Remember to change the cluster name and context variables each time you repeat the steps.

      export CLUSTER_NAME=<cluster-name>
    export CLUSTER_CONTEXT=<cluster-context>
      

Link clusters link

Link clusters to enable cross-cluster service discovery and allow traffic to be routed through east-west gateways across clusters.

1. Optional: Before you link clusters, you can check the individual readiness of each cluster for linking by running the istioctl multicluster check command for each cluster.

     istioctl multicluster check --context $CLUSTER_CONTEXT
     

   Before continuing to the next step, make sure that the following checks pass or fail as expected:
   ✅ The license in use by istiod supports multicluster.
   ✅ All istiod, ztunnel, and east-west gateway pods are healthy.
   ✅ The east-west gateway is programmed.
   ❌ Each remote peer gateway has a gloo.solo.io/PeeringSucceeded status of True. Note that this fails if you run this command prior to linking the clusters.

2. Link clusters to enable cross-cluster service discovery and allow traffic to be routed through east-west gateways across clusters. The steps vary based on whether you have access to the kubeconfig files for each cluster.

   1. Verify that the contexts for the clusters that you want to include in the multicluster mesh are listed in your kubeconfig file.

        kubectl config get-contexts
        

      • In the output, note the names of the cluster contexts, which you use in the next step to link the clusters.
      • If you have multiple kubeconfig files, you can generate a merged kubeconfig file by running the following command.

          KUBECONFIG=<kubeconfig_file1>.yaml:<file2>.yaml:<file3>.yaml kubectl config view --flatten
          

   2. Using the names of the cluster contexts, link the clusters so that they can communicate. Note that you can either link the clusters bi-directionally or asymmetrically. In a standard bi-directional setup, services in any of the linked clusters can send requests to and receive requests from the services in any of the other linked clusters. In an asymmetrical setup, you allow one cluster to send requests to another cluster, but the other cluster cannot send requests back to the first cluster.

      • Bi-directional: You can use the following istioctl command to quickly link the clusters bi-directionally. In each cluster, Gateway resources are created that use the istio-remote GatewayClass. This class allows the gateways to connect to other clusters by using the addresses of the east-west gateways.

          istioctl multicluster link --namespace istio-eastwest --contexts=<context1>,<context2>,<context3>
          

        To take a look at the Gateway resources that this command creates, you can include the --generate flag in the command.

        Example output for two clusters:

          Gateway istio-eastwest/istio-remote-peer-cluster1 applied to cluster "<cluster2_context>" pointing to cluster "<cluster1_context>" (network "cluster1")
        Gateway istio-eastwest/istio-remote-peer-cluster2 applied to cluster "<cluster1_context>" pointing to cluster "<cluster2_context>" (network "cluster2")
          

      • Asymmetrical: You can use the following istioctl command to quickly link the clusters asymmetrically. The services in the cluster in the --from flag can send requests to services in the cluster in the --to flag, but sending requests in the reverse direction is not permitted.

          istioctl multicluster link --namespace istio-eastwest --from <context1> --to <context2>
          

        To take a look at the Gateway resources that this command creates, you can include the --generate flag in the command.

        For example, this command allows services in cluster1’s mesh to send requests to services in cluster2’s mesh through cluster2’s east-west gateway. However, the reverse is not permitted: services in cluster2’s mesh cannot send requests through cluster1’s east-west gateway to services in cluster1.

          istioctl multicluster link --namespace istio-eastwest --from cluster1 --to cluster2
          

        Example output:

          Gateway istio-eastwest/istio-remote-peer-cluster2 applied to cluster "<cluster1_context>" pointing to cluster "<cluster2_context>" (network "cluster2")
          

   3. NodePort-based cross-cluster traffic: If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, annotate the generated peering gateways so that cross-cluster traffic through them resolves to the NodePort address. As with the east-west gateways, the peering gateways are still created with a stable IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address. Note that the HBONE listener that is created by default on this gateway is unused, because traffic is routed through the NodePort directly.

        kubectl annotate gateway istio-remote-peer-${REMOTE_CLUSTER1} -n istio-eastwest peering.solo.io/preferred-data-plane-service-type=NodePort --context ${CLUSTER_CONTEXT}
        

        kubectl annotate gateway istio-remote-peer-${REMOTE_CLUSTER2} -n istio-eastwest peering.solo.io/preferred-data-plane-service-type=NodePort --context ${CLUSTER_CONTEXT}
        

   If you do not have access to all kubeconfig files for the clusters you want to link, or if you cannot combine the cluster contexts into one kubeconfig file, you can link the clusters by declaratively creating istio-remote peer gateways.

   Note that you can either link the clusters bi-directionally or asymmetrically. In a standard bi-directional setup, services in any of the linked clusters can send requests to and receive requests from the services in any of the other linked clusters. In an asymmetrical setup, you allow one cluster to send requests to another cluster, but the other cluster cannot send requests back to the first cluster.

   Bi-directional: You can use the following Gateway resources to create an istio-remote peer gateway in each cluster. The istio-remote GatewayClass allows the gateways to connect to other clusters by using the addresses of the east-west gateways.

   1. Get the addresses of the east-west gateway in each cluster. The following commands show examples for two clusters.

        export CLUSTER1_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context $REMOTE_CONTEXT1 -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
      export CLUSTER2_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context $REMOTE_CONTEXT2 -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
      
      echo "Cluster1 east-west gateway: $CLUSTER1_EW_ADDRESS"
      echo "Cluster2 east-west gateway: $CLUSTER2_EW_ADDRESS"
        

   2. Using the east-west gateway addresses, create a Gateway resource in each cluster to represent the other cluster.

      • In the labels section, be sure to update the locality labels according to the region and zone of each cluster. For more information about locality support, see the release notes.
      • If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, uncomment the peering.solo.io/preferred-data-plane-service-type: NodePort annotation from each Gateway resource. As with the east-west gateways, the peering gateways must still be created with a stable IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address. Additionally, you can comment out the HBONE listener in each gateway, because traffic is routed through the NodePort directly.

        kubectl apply --context $REMOTE_CONTEXT1 -f- <<EOF
      apiVersion: gateway.networking.k8s.io/v1
      kind: Gateway
      metadata:
        annotations:
          gateway.istio.io/service-account: istio-eastwest
          gateway.istio.io/trust-domain: $REMOTE_CLUSTER2
          # Uncomment for NodePort-based cross-cluster traffic
          # peering.solo.io/preferred-data-plane-service-type: NodePort
        labels:
          topology.istio.io/network: $REMOTE_CLUSTER2
          topology.kubernetes.io/region: "<cluster2_region>"
          topology.kubernetes.io/zone: "<cluster2_zone>"
        name: istio-remote-peer-$REMOTE_CLUSTER2
        namespace: istio-eastwest
      spec:
        addresses:
        - type: IPAddress
          value: $CLUSTER2_EW_ADDRESS
        gatewayClassName: istio-remote
        listeners:
        # Comment HBONE out for NodePort-based cross-cluster traffic
        - name: cross-network
          port: 15008
          protocol: HBONE
          tls:
            mode: Passthrough
        - name: xds-tls
          port: 15012
          protocol: TLS
          tls:
            mode: Passthrough
      EOF
      
      kubectl apply --context $REMOTE_CONTEXT2 -f- <<EOF
      apiVersion: gateway.networking.k8s.io/v1
      kind: Gateway
      metadata:
        annotations:
          gateway.istio.io/service-account: istio-eastwest
          gateway.istio.io/trust-domain: $REMOTE_CLUSTER1
          # Uncomment for NodePort-based cross-cluster traffic
          # peering.solo.io/preferred-data-plane-service-type: NodePort
        labels:
          topology.istio.io/network: $REMOTE_CLUSTER1
          topology.kubernetes.io/region: "<cluster1_region>"
          topology.kubernetes.io/zone: "<cluster1_zone>"
        name: istio-remote-peer-$REMOTE_CLUSTER1
        namespace: istio-eastwest
      spec:
        addresses:
        - type: IPAddress
          value: $CLUSTER1_EW_ADDRESS
        gatewayClassName: istio-remote
        listeners:
        # Comment HBONE out for NodePort-based cross-cluster traffic
        - name: cross-network
          port: 15008
          protocol: HBONE
          tls:
            mode: Passthrough
        - name: xds-tls
          port: 15012
          protocol: TLS
          tls:
            mode: Passthrough
      EOF
        

   Asymmetrical: You can use the following Gateway resources to create an istio-remote peer gateway in only some clusters. The istio-remote GatewayClass allows the gateway in one cluster to connect to another cluster by using the address of the east-west gateway, but sending requests in the reverse direction is not permitted.

   3. Get the address of the east-west gateway in the cluster that you want to send traffic to. The following command shows an example for cluster2.

        export CLUSTER2_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context $REMOTE_CONTEXT2 -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
      
      echo "Cluster2 east-west gateway: $CLUSTER2_EW_ADDRESS"
        

   4. Using the east-west gateway address, create a Gateway resource in the cluster that you want to send requests from. For example, this Gateway resource allows services in cluster1’s mesh to send requests to services in cluster2’s mesh through cluster2’s east-west gateway. However, the reverse is not permitted: services in cluster2’s mesh cannot send requests through cluster1’s east-west gateway to services in cluster1.

      • In the labels section, be sure to update the locality labels according to the region and zone of each cluster. For more information about locality support, see the release notes.
      • If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, uncomment the peering.solo.io/preferred-data-plane-service-type: NodePort annotation from each Gateway resource. As with the east-west gateways, the peering gateway must still be created with a stable IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address. Additionally, you can comment out the HBONE listener in each gateway, because traffic is routed through the NodePort directly.

        kubectl apply --context $REMOTE_CONTEXT1 -f- <<EOF
      apiVersion: gateway.networking.k8s.io/v1
      kind: Gateway
      metadata:
        annotations:
          gateway.istio.io/service-account: istio-eastwest
          gateway.istio.io/trust-domain: $REMOTE_CLUSTER2
          # Uncomment for NodePort-based cross-cluster traffic
          # peering.solo.io/preferred-data-plane-service-type: NodePort
        labels:
          topology.istio.io/network: $REMOTE_CLUSTER2
          topology.kubernetes.io/region: "<cluster2_region>"
          topology.kubernetes.io/zone: "<cluster2_zone>"
        name: istio-remote-peer-$REMOTE_CLUSTER2
        namespace: istio-eastwest
      spec:
        addresses:
        - type: IPAddress
          value: $CLUSTER2_EW_ADDRESS
        gatewayClassName: istio-remote
        listeners:
        # Comment HBONE out for NodePort-based cross-cluster traffic
        - name: cross-network
          port: 15008
          protocol: HBONE
          tls:
            mode: Passthrough
        - name: xds-tls
          port: 15012
          protocol: TLS
          tls:
            mode: Passthrough
      EOF
        

3. For each cluster, verify that peer linking was successful by running the istioctl multicluster check command.

     istioctl multicluster check --context $CLUSTER_CONTEXT
     

   In this example output for cluster1, the license is valid, all Istio pods are healthy, and the east-west gateway is programmed. The remote peer gateways for linking to cluster2 and cluster3 both have a gloo.solo.io/PeeringSucceeded status of True.

     ✅ License Check: license is valid for multicluster
   ✅ Pod Check (istiod): all pods healthy
   ✅ Pod Check (ztunnel): all pods healthy
   ✅ Pod Check (eastwest gateway): all pods healthy
   ✅ Gateway Check: all eastwest gateways programmed
   ✅ Peers Check: all clusters connected
     

Option 2: Automatically link clusters (beta) link

In each cluster, use the Gloo Operator to create the service mesh components, and create an east-west gateway so that traffic requests can be routed cross-cluster. Then, use the Gloo management plane to automate multicluster linking, which enables cross-cluster service discovery.

Enable automatic peering of clusters link

Upgrade Gloo Mesh in your multicluster setup to enable the ConfigDistribution feature flag and install the enterprise CRDs, which are required for Gloo Mesh to automate peering and distribute gateways between clusters.

1. Upgrade your gloo-platform-crds Helm release in the management cluster to include the following settings.

     helm get values gloo-platform-crds -n gloo-mesh -o yaml --kube-context ${MGMT_CONTEXT} > mgmt-crds.yaml
   helm upgrade gloo-platform-crds gloo-platform/gloo-platform-crds \
       --kube-context ${MGMT_CONTEXT} \
       --namespace gloo-mesh \
       -f mgmt-crds.yaml \
       --set featureGates.ConfigDistribution=true \
       --set installEnterpriseCrds=true
     

2. Upgrade your gloo-platform Helm release in the management cluster to include the following settings.

     helm get values gloo-platform -n gloo-mesh -o yaml --kube-context ${MGMT_CONTEXT} > mgmt-plane.yaml
   helm upgrade gloo-platform gloo-platform/gloo-platform \
       --kube-context ${MGMT_CONTEXT} \
       --namespace gloo-mesh \
       -f mgmt-plane.yaml \
       --set featureGates.ConfigDistribution=true
     

3. Upgrade your gloo-platform-crds Helm release in each workload cluster to include the following settings. Repeat this step for each workload cluster.

     helm get values gloo-platform-crds -n gloo-mesh -o yaml --kube-context ${CLUSTER_CONTEXT} > crds.yaml
   helm upgrade gloo-platform-crds gloo-platform/gloo-platform-crds \
       --kube-context ${CLUSTER_CONTEXT} \
       --namespace gloo-mesh \
       -f crds.yaml \
       --set installEnterpriseCrds=true
     

Create a shared root of trust link

Create a shared root of trust for each cluster in the multicluster setup, including the management cluster. This can be achieved by providing a root certificate signed by a PKI provider, or a custom root certificate created for this purpose. The root certificate signs a unique intermediate CA certificate for each cluster.

  curl -L https://istio.io/downloadIstio | ISTIO_VERSION=${ISTIO_VERSION} sh -
cd istio-${ISTIO_VERSION}

mkdir -p certs
pushd certs
make -f ../tools/certs/Makefile.selfsigned.mk root-ca

function create_cacerts_secret() {
  context=${1:?context}
  cluster=${2:?cluster}
  make -f ../tools/certs/Makefile.selfsigned.mk ${cluster}-cacerts
  kubectl --context=${context} create ns istio-system || true
  kubectl --context=${context} create secret generic cacerts -n istio-system \
    --from-file=${cluster}/ca-cert.pem \
    --from-file=${cluster}/ca-key.pem \
    --from-file=${cluster}/root-cert.pem \
    --from-file=${cluster}/cert-chain.pem
}

create_cacerts_secret ${MGMT_CONTEXT} ${MGMT_CLUSTER}
create_cacerts_secret ${REMOTE_CONTEXT1} ${REMOTE_CLUSTER1}
create_cacerts_secret ${REMOTE_CONTEXT2} ${REMOTE_CLUSTER2}

cd ../..
  

Deploy mesh components link

1. Save the name and kubeconfig context of a cluster where you want to install Istio in the following environment variables. Each time you repeat the steps in this guide, you change these variables to the next workload cluster’s name and context. Note that to use automated multicluster peering, you must complete these steps to install a service mesh in the management cluster as well as your workload clusters.

     export CLUSTER_NAME=<cluster-name>
   export CLUSTER_CONTEXT=<cluster-context>
     

2. Apply the CRDs for the Kubernetes Gateway API to your cluster, which are required to create components such as waypoint proxies for L7 traffic policies, gateways with the Gateway resource, and more.

     kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.4.0/standard-install.yaml --context ${CLUSTER_CONTEXT}
     

3. Install the Gloo Operator to the gloo-mesh namespace. This operator deploys and manages your Istio installation. For more information, see the Helm reference. Note that if you already installed Gloo Mesh, you can optionally reference the secret that Gloo Mesh (OSS APIs) automatically creates for your license in the –set manager.env.SOLO_ISTIO_LICENSE_KEY_SECRET_REF=gloo-mesh/license-keys flag instead.

     helm install gloo-operator oci://us-docker.pkg.dev/solo-public/gloo-operator-helm/gloo-operator \
     --version 0.4.2 \
     -n gloo-mesh \
     --create-namespace \
     --kube-context ${CLUSTER_CONTEXT} \
     --set manager.env.SOLO_ISTIO_LICENSE_KEY=${GLOO_MESH_LICENSE_KEY}
     

4. Verify that the operator pod is running.

     kubectl get pods -n gloo-mesh --context ${CLUSTER_CONTEXT} -l app.kubernetes.io/name=gloo-operator
     

   Example output:

     gloo-operator-78d58d5c7b-lzbr5     1/1     Running   0          48s
     

5. Apply the following configmap and ServiceMeshController for the Gloo Operator to enable multicluster peering and deploy a service mesh.

     kubectl apply -n gloo-mesh --context ${CLUSTER_CONTEXT} -f -<<EOF
   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: gloo-extensions-config
     namespace: gloo-mesh
   data:
     beta: |
       serviceMeshController:
         multiClusterMode: Peering
     values.istiod: |
       env:
         PEERING_AUTOMATIC_LOCAL_GATEWAY: "true"	
   EOF
   ---
   kubectl apply -n gloo-mesh --context ${CLUSTER_CONTEXT} -f -<<EOF
   apiVersion: operator.gloo.solo.io/v1
   kind: ServiceMeshController
   metadata:
     name: managed-istio
     labels:
       app.kubernetes.io/name: managed-istio
   spec:
     cluster: ${CLUSTER_NAME}
     network: ${CLUSTER_NAME}
     dataplaneMode: Ambient # required for multicluster setups
     installNamespace: istio-system
     version: ${ISTIO_VERSION}
   EOF
     

   info

   Note that the operator detects your cloud provider and cluster platform, and configures the necessary settings required for that platform for you. For example, if you create an ambient mesh in an OpenShift cluster, no OpenShift-specific settings are required in the ServiceMeshController, because the operator automatically sets the appropriate settings for OpenShift and your specific cloud provider accordingly.
   
   If you set the installNamespace to a namespace other than gloo-system, gloo-mesh, or istio-system, you must include the ‐‐set manager.env.WATCH_NAMESPACES=<namespace> setting.

6. Verify that the istiod control plane, Istio CNI, and ztunnel pods are running.

     kubectl get pods -n istio-system --context ${CLUSTER_CONTEXT}
     

   Example output:

     NAME                          READY   STATUS    RESTARTS   AGE
   istio-cni-node-6s5nk          1/1     Running   0          2m53s
   istio-cni-node-blpz4          1/1     Running   0          2m53s
   istiod-gloo-bb86b959f-msrg7   1/1     Running   0          2m45s
   istiod-gloo-bb86b959f-w29cm   1/1     Running   0          3m
   ztunnel-mx8nw                 1/1     Running   0          2m52s
   ztunnel-w8r6c                 1/1     Running   0          2m52s
     

7. Create an east-west gateway in the istio-eastwest namespace. In each cluster, the east-west gateway is implemented as a ztunnel that facilitates traffic between services across clusters in your multicluster mesh. You can use either LoadBalancer or NodePort addresses for cross-cluster traffic.

   1. Create the istio-eastwest namespace.

        kubectl create namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   2. Use the following istioctl command to quickly create the east-west gateway. To take a look at the Gateway resource that this command creates, you can include the --generate flag in the command. Cross-cluster traffic though this gateway resolves to the LoadBalancer address.

        istioctl multicluster expose --namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   Note that the gateway must still be created with a stable IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address.

   1. Create the istio-eastwest namespace.

        kubectl create namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   2. Use the following istioctl command to quickly create the east-west gateway. To take a look at the Gateway resource that this command creates, you can include the --generate flag in the command. Note that the HBONE listener that is created by default on this gateway is unused, because traffic is routed through the NodePort directly.

        istioctl multicluster expose --namespace istio-eastwest --context ${CLUSTER_CONTEXT}
        

   3. Annotate the gateway so that cross-cluster traffic through this gateway resolves to the NodePort address.

        kubectl annotate gateway istio-eastwest -n istio-eastwest peering.solo.io/data-plane-service-type=NodePort --context ${CLUSTER_CONTEXT}
        

8. For each cluster that you want to include in the multicluster mesh setup, including the management cluster, repeat these steps to install the Gloo Operator, service mesh components, and east-west gateway in each cluster. Remember to change the cluster name and context variables each time you repeat the steps.

     export CLUSTER_NAME=<cluster-name>
   export CLUSTER_CONTEXT=<cluster-context>
     

Review remote peer gateways link

After you complete the steps for each cluster, verify that Gloo Mesh successfully created and distributed the remote peering gateways. These gateways use the istio-remote GatewayClass, which allows the istiod control plane in each cluster to discover the east-west gateway addresses of other clusters. Gloo Mesh generates one istio-remote resource in the management cluster for each connected workload cluster, and then distributes the gateway to each cluster respectively.

1. Verify that an istio-remote gateway for each connected cluster is copied to the management cluster.

     kubectl get gateways -n istio-eastwest --context $MGMT_CONTEXT
     

   In this example output, the istio-remote gateways that were auto-generated for workload clusters cluster1 and cluster2 are copied to the management cluster, alongside the management cluster’s own istio-remote gateway and east-west gateway.

     NAMESPACE        NAME                            CLASS           ADDRESS                                                                   PROGRAMMED   AGE
   istio-eastwest   istio-eastwest                 istio-eastwest   a7f6f1a2611fc4eb3864f8d688622fd4-1234567890.us-east-1.elb.amazonaws.com   True         6s
   istio-eastwest   istio-remote-peer-cluster1     istio-remote     a5082fe9522834b8192a6513eb8c6b01-0987654321.us-east-1.elb.amazonaws.com   True         4s
   istio-eastwest   istio-remote-peer-cluster2     istio-remote     aaad62dc3ffb142a1bfc13df7fe9665b-5678901234.us-east-1.elb.amazonaws.com   True         4s
   istio-eastwest   istio-remote-peer-mgmt         istio-remote     a7f6f1a2611fc4eb3864f8d688622fd4-1234567890.us-east-1.elb.amazonaws.com   True         4s
     

2. In each cluster, verify that all istio-remote gateways are successfully distributed to all workload clusters. This ensures that services in each workload cluster can now access the east-west gateways in other clusters of the multicluster mesh setup.

     kubectl get gateways -n istio-eastwest --context $CLUSTER_CONTEXT
   ```
   
   3. In each cluster, verify that peer linking was successful by running the `istioctl multicluster check` command.
      ```sh
      istioctl multicluster check --context $CLUSTER_CONTEXT
      ```
   
      In this example output for cluster1, the license is valid, all Istio pods are healthy, and the east-west gateway is programmed. The remote peer gateways for linking to cluster2 and cluster3 both have a `gloo.solo.io/PeeringSucceeded` status of `True`.
      ```
      ✅ License Check: license is valid for multicluster
      ✅ Pod Check (istiod): all pods healthy
      ✅ Pod Check (ztunnel): all pods healthy
      ✅ Pod Check (eastwest gateway): all pods healthy
      ✅ Gateway Check: all eastwest gateways programmed
      ✅ Peers Check: all clusters connected
      ```
     

Next link

Add apps to the sidecar mesh. For multicluster setups, this includes making specific services available across your linked cluster setup.

ServiceMeshController reference link

Review the commonly configured fields for the ServiceMeshController custom resource. For the full list of available options, see the ServiceMeshController API reference.

Advanced settings configuration link

You can set advanced Istio configuation by creating a configmap. For example, you might need to specify settings for istiod such as discovery selectors, pod and service annotations, affinities, tolerations, or node selectors.

The following gloo-extensions-config example configmap sets all possible fields for demonstration purposes. Note that in some guides in this documentation set, Helm extension settings such as data.values.istiod are defined for specific settings in the configmap. However, these settings are used only when necessary, and are not recommended for other general use cases.

  apiVersion: v1
kind: ConfigMap
metadata:
  name: gloo-extensions-config
  namespace: gloo-mesh
data:
  stable: |
    serviceMeshController:
      istiod:
        discoverySelectors:
          - matchLabels:
              foo: bar
        topology:
          affinity:
            podAntiAffinity:
              preferredDuringSchedulingIgnoredDuringExecution:
              - podAffinityTerm:
                  labelSelector:
                    matchExpressions:
                    - key: foo
                      operator: In
                      values:
                      - bar
                  topologyKey: foo.io/bar
                weight: 80
          nodeSelector:
            foo: bar
          tolerations:
            - key: t1
              operator: Equal
              value: v1
        deployment:
          podAnnotations:
            foo: bar
        serviceAnnotations:
          foo: bar
  beta: |
    serviceMeshController:
      cni:
        confDir: /foo/bar
        binDir: /foo/bar