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Set up a multi-cloud or hybrid mesh

This page explains how to set up a multi-cloud or hybrid mesh for the following platforms:

  • Hybrid: GKE on Google Cloud and Anthos clusters on VMware (preview)
  • Hybrid: GKE on Google Cloud and Anthos clusters on bare metal (preview)
  • Multi-cloud: GKE on Google Cloud and Amazon EKS (preview)

By following these instructions you set up two clusters, but you can extend this process to incorporate any number of clusters into your mesh.

Prerequisites

  • All clusters must be registered to the same fleet host project.
  • All GKE clusters must be in a shared VPC configuration on the same network.
  • The cluster's Kubernetes control plane address and the gateway address need to be reachable from every cluster in the mesh. The GCP project in which GKE clusters are located should be allowed to create external load balancing types. We recommend that you use authorized networks and VPC firewall rules to restrict the access.
  • Private clusters, including GKE private clusters, are not supported. If you use On-Premises clusters including Anthos clusters on VMware and Anthos clusters on bare metal, the Kubernetes control plane address and the gateway address need to be reachable from pods in GKE clusters. We recommend that you use CloudVPN to connect the GKE cluster's subnet with the On-Premises cluster's network.
  • If you use Istio CA, use the same custom root certificate for all clusters.

Before you begin

This guide assumes you installed Anthos Service Mesh using the asmcli tool. You need asmcli and the configuration package that asmcli downloads to the directory that you specified in --output_dir when you ran asmcli install. For more information, see Install dependent tools and validate cluster to:

You need access to the kubeconfig files for all the clusters that you are setting up in the mesh. For the GKE cluster, in order to create a new kubeconfig file for the cluster, you can export KUBECONFIG env with the complete path of file as value in your terminal and generate the kubeconfig entry.

Set up environment variables and placeholders

You need the following environment variables when you install the east-west gateway.

  1. Create an environment variable for the project number. In the following command, replace FLEET_PROJECT_ID with the project ID of the fleet host project.

    export PROJECT_NUMBER=$(gcloud projects describe FLEET_PROJECT_ID --format="value(projectNumber)")
    
  2. Create an environment variable for the mesh identifier.

    export MESH_ID="proj-${PROJECT_NUMBER}"
    
  3. Create environment variables for the network names.

    • GKE clusters default to the cluster network name:

      export NETWORK_1="PROJECT_ID-CLUSTER_NETWORK"

    • Other clusters use default:

      export NETWORK_2="default"

    Note that If you installed Anthos Service Mesh on other clusters with different values for --network_id, then you should pass the same values to value to NETWORK_2.

Install the east-west gateway

  1. Install a gateway in CLUSTER_1 (your GKE cluster) that is dedicated to east-west traffic to CLUSTER_2 (your multi-cloud or on-premise cluster):

    asm/istio/expansion/gen-eastwest-gateway.sh \
        --mesh ${MESH_ID} \
        --network ${NETWORK_1}  \
        --revision asm-1153-6 | \
        istioctl --kubeconfig=PATH_TO_KUBECONFIG_1 install -y -f -
    

    Note that this gateway is public on the Internet by default. Production systems might require additional access restrictions, for example firewall rules, to prevent external attacks.

  2. Install a gateway in CLUSTER_2 that is dedicated to east-west traffic for CLUSTER_1.

    asm/istio/expansion/gen-eastwest-gateway.sh \
        --mesh ${MESH_ID} \
        --network ${NETWORK_2} \
        --revision asm-1153-6 | \
        istioctl --kubeconfig=PATH_TO_KUBECONFIG_2 install -y -f -
    

Expose services

Since the clusters are on separate networks, you need to expose all services (\*.local) on the east-west gateway in both clusters. While this gateway is public on the internet, services behind it can only be accessed by services with a trusted mTLS certificate and workload ID, just as if they were on the same network.

Expose services via the east-west gateway for every cluster

    kubectl --kubeconfig=PATH_TO_KUBECONFIG_1 apply -n istio-system -f \
        asm/istio/expansion/expose-services.yaml
    kubectl --kubeconfig=PATH_TO_KUBECONFIG_2 apply -n istio-system -f \
        asm/istio/expansion/expose-services.yaml

Enable endpoint discovery

Run the asmcli create-mesh command to enable endpoint discovery. This example only shows two clusters, but you can run the command to enable endpoint discovery on additional clusters, subject to the GKE Hub service limit.

  ./asmcli create-mesh \
      FLEET_PROJECT_ID \
      PATH_TO_KUBECONFIG_1 \
      PATH_TO_KUBECONFIG_2

Verify multicluster connectivity

This section explains how to deploy the sample HelloWorld and Sleep services to your multi-cluster environment to verify that cross-cluster load balancing works.

Enable sidecar injection

  1. Locate the revision label value, which you use in later steps. The step depends on your Anthos Service Mesh type (either managed or in-cluster).

    Managed

    Use the following command to locate the revision label, which you will use in later steps.

    kubectl get controlplanerevision -n istio-system

    The output looks similar to the following:

     NAME                RECONCILED   STALLED   AGE
     asm-managed-rapid   True         False     89d
     

    In the output, under the NAME column, note the value of the revision label. In this example, the value is asm-managed-rapid. Use the revision value in the steps in the next section.

    In-cluster

    Use the following command to locate the revision label, which you will use in later steps.

    kubectl -n istio-system get pods -l app=istiod --show-labels

    The output looks similar to the following:

     NAME                                READY   STATUS    RESTARTS   AGE   LABELS
     istiod-asm-173-3-5788d57586-bljj4   1/1     Running   0          23h   app=istiod,istio.io/rev=asm-173-3,istio=istiod,pod-template-hash=5788d57586
     istiod-asm-173-3-5788d57586-vsklm   1/1     Running   1          23h   app=istiod,istio.io/rev=asm-173-3,istio=istiod,pod-template-hash=5788d57586
     

    In the output, under the LABELS column, note the value of the istiod revision label, which follows the prefix istio.io/rev=. In this example, the value is asm-173-3. Use the revision value in the steps in the next section.

Install the HelloWorld service

  1. Create the sample namespace and the Service Definition in each cluster. In the following command, substitute REVISION with the istiod revision label that you noted from the previous step.

    for CTX in ${CTX_1} ${CTX_2}
    do
        kubectl create --context=${CTX} namespace sample
        kubectl label --context=${CTX} namespace sample \
            istio-injection- istio.io/rev=REVISION --overwrite
    done
    

    where REVISION is the istiod revision label that you previously noted.

    The output is:

    label "istio-injection" not found.
    namespace/sample labeled
    

    You can safely ignore label "istio-injection" not found.

  2. Create the HelloWorld service in both clusters:

    kubectl create --context=${CTX_1} \
        -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \
        -l service=helloworld -n sample
    
    kubectl create --context=${CTX_2} \
        -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \
        -l service=helloworld -n sample
    

Deploy HelloWorld v1 and v2 to each cluster

  1. Deploy HelloWorld v1 to CLUSTER_1 and v2 to CLUSTER_2, which helps later to verify cross-cluster load balancing:

    kubectl create --context=${CTX_1} \
      -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \
      -l version=v1 -n sample
    kubectl create --context=${CTX_2} \
      -f ${SAMPLES_DIR}/samples/helloworld/helloworld.yaml \
      -l version=v2 -n sample
  2. Confirm HelloWorld v1 and v2 are running using the following commands. Verify that the output is similar to that shown.:

    kubectl get pod --context=${CTX_1} -n sample
    NAME                            READY     STATUS    RESTARTS   AGE
    helloworld-v1-86f77cd7bd-cpxhv  2/2       Running   0          40s
    kubectl get pod --context=${CTX_2} -n sample
    NAME                            READY     STATUS    RESTARTS   AGE
    helloworld-v2-758dd55874-6x4t8  2/2       Running   0          40s

Deploy the Sleep service

  1. Deploy the Sleep service to both clusters. This pod generates artificial network traffic for demonstration purposes:

    for CTX in ${CTX_1} ${CTX_2}
    do
        kubectl apply --context=${CTX} \
            -f ${SAMPLES_DIR}/samples/sleep/sleep.yaml -n sample
    done
    
  2. Wait for the Sleep service to start in each cluster. Verify that the output is similar to that shown:

    kubectl get pod --context=${CTX_1} -n sample -l app=sleep
    NAME                             READY   STATUS    RESTARTS   AGE
    sleep-754684654f-n6bzf           2/2     Running   0          5s
    kubectl get pod --context=${CTX_2} -n sample -l app=sleep
    NAME                             READY   STATUS    RESTARTS   AGE
    sleep-754684654f-dzl9j           2/2     Running   0          5s

Verify cross-cluster load balancing

Call the HelloWorld service several times and check the output to verify alternating replies from v1 and v2:

  1. Call the HelloWorld service:

    kubectl exec --context="${CTX_1}" -n sample -c sleep \
        "$(kubectl get pod --context="${CTX_1}" -n sample -l \
        app=sleep -o jsonpath='{.items[0].metadata.name}')" \
        -- /bin/sh -c 'for i in $(seq 1 20); do curl -sS helloworld.sample:5000/hello; done'
    

    The output is similar to that shown:

    Hello version: v2, instance: helloworld-v2-758dd55874-6x4t8
    Hello version: v1, instance: helloworld-v1-86f77cd7bd-cpxhv
    ...
  2. Call the HelloWorld service again:

    kubectl exec --context="${CTX_2}" -n sample -c sleep \
        "$(kubectl get pod --context="${CTX_2}" -n sample -l \
        app=sleep -o jsonpath='{.items[0].metadata.name}')" \
        -- /bin/sh -c 'for i in $(seq 1 20); do curl -sS helloworld.sample:5000/hello; done'
    

    The output is similar to that shown:

    Hello version: v2, instance: helloworld-v2-758dd55874-6x4t8
    Hello version: v1, instance: helloworld-v1-86f77cd7bd-cpxhv
    ...

Congratulations, you've verified your load-balanced, multi-cluster Anthos Service Mesh!

Clean up

When you finish verifying load balancing, remove the HelloWorld and Sleep service from your cluster.

kubectl delete ns sample --context ${CTX_1}
kubectl delete ns sample --context ${CTX_2}