Helm

Use Helm to link ambient service meshes across multiple clusters.

Overview

In this guide, you deploy an ambient 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 ambient 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 Solo Enterprise for kgateway, to services in your mesh across all clusters.

The following diagram demonstrates an ambient mesh setup across multiple clusters. For more information about the components that are installed in these steps, see the ambient components overview.

Figure: Multicluster ambient mesh set up with the Solo distribution of Istio and Solo Enterprise for kgateway.

Considerations

Before you set up a multicluster ambient mesh, review the following considerations and requirements.

License requirements

Multicluster capabilities require an Enterprise level license for Solo Enterprise for Istio. If you do not have one, contact an account representative.

Version requirements

Review the following known Istio version requirements and restrictions.

If you use Istio versions 1.27.7, 1.28.4, 1.29.0 or later, and you install the Solo Enterprise for Istio management plane into a namespace other than gloo-mesh, you must allow that namespace by listing it in the DEBUG_ENDPOINT_AUTH_ALLOWED_NAMESPACES environment variable of your istiod installation. For more information, see the release notes.
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 Solo Enterprise for Istio) on AWS Fargate. For more information, see the Amazon EKS issue.

Platform requirements

The steps in the following sections have options for deploying an ambient mesh to either Kubernetes or OpenShift clusters.

If you use OpenShift clusters, complete the following steps before you begin:

Set routingViaHost: true in the Cluster Network Operator to enable OVN-Kubernetes local gateway mode. For more information, see the Platform-specific prerequisites in the ambient mesh docs.

The commands for OpenShift in the following steps contain these required settings:

Your Helm settings must include global.platform=openshift for Istio 1.24 and later. If you instead install Istio 1.23 or earlier, you must use profile=openshift instead of the global.platform setting.
Install the istio-cni and ztunnel Helm releases in the kube-system namespace, instead of the istio-system namespace.

Revision and canary upgrade limitations

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

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 the Solo distribution of 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.
NodePort peering uses only InternalIP node addresses. Ensure that your environment is configured so that nodes are reachable via their InternalIP address. If you need to use another address type, such as ExternalIP, contact Solo for engineering design and implementation support.
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.
This feature is only supported for default network setups, and is not applicable in flat network setups.

The steps in the following guide 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

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.

Multicluster setup method

To get started, choose one of following methods for creating a multicluster mesh.

Option 1: Install and link new ambient meshes to form a multicluster mesh.
Option 2: Upgrade and link existing ambient meshes that you already installed in individual clusters.
Option 3: Automatically link clusters by using the Gloo management plane. Note that this method is a beta feature.

Option 1: Install and link new ambient meshes

In each cluster, use Helm to create the ambient 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.

Set up tools

Set your Enterprise level license for Solo Enterprise for Istio 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. Note that you might have previously saved this key in another variable, such as ${SOLO_LICENSE_KEY} or ${GLOO_MESH_LICENSE_KEY}.
```
export SOLO_ISTIO_LICENSE_KEY=<enterprise_license_key>
```
Choose the version of Istio that you want to install or upgrade to by reviewing the supported versions.

Save the Solo distribution of Istio version.

export ISTIO_VERSION=1.28.5
export ISTIO_IMAGE=${ISTIO_VERSION}-solo

Save the 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}
```
Get the Solo distribution of Istio binary and install istioctl, which you use for multicluster linking and gateway commands. This script automatically detects your OS and architecture, downloads the appropriate Solo distribution of Istio binary, and verifies the installation.
```
bash <(curl -sSfL https://raw.githubusercontent.com/solo-io/doc-examples/main/istio/install-istioctl.sh)
export PATH=${HOME}/.istioctl/bin:${PATH}
```
Save the names and kubeconfig contexts of each cluster. This guide uses two clusters as an example. To add more clusters to the multicluster setup, include them in the arrays.
```
export cluster1=<cluster1_name>
export context1=<cluster1_context>
export cluster2=<cluster2_name>
export context2=<cluster2_context>
```

Create a shared root of trust

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.

By default, the Istio CA generates a self-signed root certificate and key, and uses them to sign the workload certificates. For more information, see the Plug in CA Certificates guide in the community Istio documentation.

For demo installations, you can run the following function to quickly generate and plug in the certificates and key for the Istio CA:

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 ${context1} ${cluster1}
create_cacerts_secret ${context2} ${cluster2}

cd ../..

To enhance the security of your setup even further and have full control over the Istio CA lifecycle, you can generate and store the root and intermediate CA certificates and keys with your own PKI provider. You can then use tools such as cert-manager to send certificate signing requests on behalf of istiod to your PKI provider. Cert-manager stores the signed intermediate certificates and keys in the cacerts Kubernetes secret so that istiod can use these credentials to issue leaf certificates for the workloads in the service mesh. You can set up cert-manager to also check the certificates and renew them before they expire.

AWS Private CA issuer and cert-manager: For an architectural overview of this certificate setup, see Bring your own Istio CAs with AWS. For steps on how to deploy this certificate setup, check out this Solo.io blog post. Be sure to repeat the steps so that a cacerts secret exists in each cluster.

Deploy ambient components

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 ${context1}
kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.4.0/standard-install.yaml --context ${context2}

Install the base chart, which contains the CRDs and cluster roles required to set up Istio, in both clusters.

function install_base() {
  context=${1:?context}
  helm upgrade --install istio-base oci://${HELM_REPO}/base \
  --namespace istio-system \
  --create-namespace \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
defaultRevision: ""
profile: ambient
EOF
}

install_base ${context1}
install_base ${context2}

function install_base() {
  context=${1:?context}
  helm upgrade --install istio-base oci://${HELM_REPO}/base \
  --namespace istio-system \
  --create-namespace \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
defaultRevision: ""
profile: ambient
global:
  platform: openshift
EOF
}

install_base ${context1}
install_base ${context2}

You can optionally verify that the CRDs are successfully installed in both clusters.

kubectl get crds -l app.kubernetes.io/instance=istio-base --kube-context ${context1}
kubectl get crds -l app.kubernetes.io/instance=istio-base --kube-context ${context2}

Example output:

NAME                                       CREATED AT
authorizationpolicies.security.istio.io    2025-12-16T22:56:00Z
destinationrules.networking.istio.io       2025-12-16T22:56:00Z
envoyfilters.networking.istio.io           2025-12-16T22:56:00Z
gateways.networking.istio.io               2025-12-16T22:56:00Z
peerauthentications.security.istio.io      2025-12-16T22:56:00Z
proxyconfigs.networking.istio.io           2025-12-16T22:56:00Z
requestauthentications.security.istio.io   2025-12-16T22:56:00Z
segments.admin.solo.io                     2025-12-16T22:56:00Z
serviceentries.networking.istio.io         2025-12-16T22:56:00Z
sidecars.networking.istio.io               2025-12-16T22:56:00Z
telemetries.telemetry.istio.io             2025-12-16T22:56:00Z
virtualservices.networking.istio.io        2025-12-16T22:56:00Z
wasmplugins.extensions.istio.io            2025-12-16T22:56:00Z
workloadentries.networking.istio.io        2025-12-16T22:56:00Z
workloadgroups.networking.istio.io         2025-12-16T22:56:00Z

Create the istiod control plane in both clusters.

function install_istiod() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade --install istiod oci://${HELM_REPO}/istiod \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
env:
  # Assigns IP addresses to multicluster services
  PILOT_ENABLE_IP_AUTOALLOCATE: "true"
  # Required when meshConfig.trustDomain is set
  PILOT_SKIP_VALIDATE_TRUST_DOMAIN: "true"
  # Disable community Istio multicluster mechanisms
  DISABLE_LEGACY_MULTICLUSTER: "true"
global:
  hub: ${REPO}
  multiCluster:
    clusterName: ${cluster}
  network: ${cluster}
  proxy:
    clusterDomain: cluster.local
  tag: ${ISTIO_IMAGE}
meshConfig:
  accessLogFile: /dev/stdout
  defaultConfig:
    proxyMetadata:
      ISTIO_META_DNS_CAPTURE: "true"
  # Assign each cluster a unique trust domain to apply policies to specific clusters
  trustDomain: "${cluster}.local"
pilot:
  cni:
    namespace: istio-system
    enabled: true
# Required to enable multicluster support
platforms:
  peering:
    enabled: true
profile: ambient
license:
  value: ${SOLO_ISTIO_LICENSE_KEY}
  # Uncomment if you prefer to specify your license secret
  # instead of an inline value.
  # secretRef:
  #   name:
  #   namespace:
EOF
}

install_istiod ${context1} ${cluster1}
install_istiod ${context2} ${cluster2}

function install_istiod() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade --install istiod oci://${HELM_REPO}/istiod \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
env:
  # Assigns IP addresses to multicluster services
  PILOT_ENABLE_IP_AUTOALLOCATE: "true"
  # Required when meshConfig.trustDomain is set
  PILOT_SKIP_VALIDATE_TRUST_DOMAIN: "true"
  # Disable community Istio multicluster mechanisms
  DISABLE_LEGACY_MULTICLUSTER: "true"
global:
  hub: ${REPO}
  multiCluster:
    clusterName: ${cluster}
  network: ${cluster}
  platform: openshift
  proxy:
    clusterDomain: cluster.local
  tag: ${ISTIO_IMAGE}
meshConfig:
  accessLogFile: /dev/stdout
  defaultConfig:
    proxyMetadata:
      ISTIO_META_DNS_CAPTURE: "true"
  # Assign each cluster a unique trust domain to apply policies to specific clusters
  trustDomain: "${cluster}.local"
pilot:
  cni:
    namespace: kube-system
    enabled: true
# Required to enable multicluster support
platforms:
  peering:
    enabled: true
profile: ambient
license:
  value: ${SOLO_ISTIO_LICENSE_KEY}
  # Uncomment if you prefer to specify your license secret
  # instead of an inline value.
  # secretRef:
  #   name:
  #   namespace:
EOF
}

install_istiod ${context1} ${cluster1}
install_istiod ${context2} ${cluster2}

Install the Istio CNI node agent daemonset in both clusters.

function install_cni() {
  context=${1:?context}
  helm upgrade --install istio-cni oci://${HELM_REPO}/cni \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
# Assigns IP addresses to multicluster services
ambient:
  dnsCapture: true
excludeNamespaces:
  - istio-system
  - kube-system
global:
  hub: ${REPO}
  tag: ${ISTIO_IMAGE}
profile: ambient
EOF
}

install_cni ${context1}
install_cni ${context2}

function install_cni() {
  context=${1:?context}
  helm upgrade --install istio-cni oci://${HELM_REPO}/cni \
  --namespace kube-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
# Assigns IP addresses to multicluster services
ambient:
  dnsCapture: true
excludeNamespaces:
  - istio-system
  - kube-system
global:
  hub: ${REPO}
  platform: openshift
  tag: ${ISTIO_IMAGE}
profile: ambient
EOF
}

install_cni ${context1}
install_cni ${context2}

Install the ztunnel daemonset in both clusters.

function install_ztunnel() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade --install ztunnel oci://${HELM_REPO}/ztunnel \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
configValidation: true
enabled: true
env:
  L7_ENABLED: "true"
  # Required when a unique trust domain is set for each cluster
  SKIP_VALIDATE_TRUST_DOMAIN: "true"
hub: ${REPO}
istioNamespace: istio-system
multiCluster:
  clusterName: ${cluster}
namespace: istio-system
network: ${cluster}
profile: ambient
proxy:
  clusterDomain: cluster.local
tag: ${ISTIO_IMAGE}
terminationGracePeriodSeconds: 29
variant: distroless
EOF
}

install_ztunnel ${context1} ${cluster1}
install_ztunnel ${context2} ${cluster2}

function install_ztunnel() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade --install ztunnel oci://${HELM_REPO}/ztunnel \
  --namespace kube-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
configValidation: true
enabled: true
env:
  L7_ENABLED: "true"
  # Required when a unique trust domain is set for each cluster
  SKIP_VALIDATE_TRUST_DOMAIN: "true"
global:
  platform: openshift
hub: ${REPO}
istioNamespace: istio-system
multiCluster:
  clusterName: ${cluster}
namespace: kube-system
network: ${cluster}
profile: ambient
proxy:
  clusterDomain: cluster.local
tag: ${ISTIO_IMAGE}
terminationGracePeriodSeconds: 29
variant: distroless
EOF
}

install_ztunnel ${context1} ${cluster1}
install_ztunnel ${context2} ${cluster2}

Verify that the components of the Istio ambient control and data plane are successfully installed in both clusters. Because the Istio CNI and ztunnel are deployed as daemon sets, the number of CNI and ztunnel pods equals the number of nodes in your cluster. Note that it might take a few seconds for the pods to become available.

kubectl get pods -A --context ${context1} | grep -E 'istio|ztunnel'
kubectl get pods -A --context ${context2} | grep -E 'istio|ztunnel'

Example output:

istiod-85c4dfd97f-mncj5      1/1     Running   0          40s
istio-cni-node-pr5rl         1/1     Running   0          9s
istio-cni-node-pvmx2         1/1     Running   0          9s
istio-cni-node-6q26l         1/1     Running   0          9s
ztunnel-tvtzn                1/1     Running   0          7s
ztunnel-vtpjm                1/1     Running   0          4s
ztunnel-hllxg                1/1     Running   0          4s

Optional: Check the istiod logs in both clusters to verify that the certificate you generated earlier is picked up by istiod.

kubectl logs deploy/istiod -n istio-system --context ${context1} | grep x509
kubectl logs deploy/istiod -n istio-system --context ${context2} | grep x509

Example output:

2025-12-16T22:59:06.783901Z     info    x509 cert - Issuer: "CN=Intermediate CA,O=Istio,L=cluster-1", Subject: "", SN: def320623729b8370172413749143836, NotBefore: "2025-12-16T22:57:06Z", NotAfter: "2035-12-14T22:59:06Z"
2025-12-16T22:59:06.783937Z     info    x509 cert - Issuer: "CN=Root CA,O=Istio", Subject: "CN=Intermediate CA,O=Istio,L=cluster-1", SN: 452d45254328667ccf8434c64c79fe789612bb5a, NotBefore: "2025-12-16T22:54:30Z", NotAfter: "2035-12-14T22:54:30Z"
2025-12-16T22:59:06.783966Z     info    x509 cert - Issuer: "CN=Root CA,O=Istio", Subject: "CN=Root CA,O=Istio", SN: 38dad68e56ab8c506ae07454801f65b134bd9580, NotBefore: "2025-12-16T22:54:30Z", NotAfter: "2035-12-14T22:54:30Z"

Label the istio-system namespace with the clusters’ network names, which you previously set to each cluster name in the global.network field of the istiod installations. The ambient control plane uses this label internally to group pods that exist in the same L3 network.
```
kubectl label namespace istio-system --context ${context1} topology.istio.io/network=${cluster1}
kubectl label namespace istio-system --context ${context2} topology.istio.io/network=${cluster2}
```
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.
Create the east-west gateway in both clusters. Cross-cluster traffic though this gateway resolves to the LoadBalancer address. For customization options, see the gateway guide in the Istio docs.
- Solo distribution of istioctl: For more information about this command, see the CLI reference.
  function create_ew_gateway_lb() { context=${1:?context} cluster=${2:?cluster} kubectl create namespace istio-eastwest --context ${context} istioctl multicluster expose --namespace istio-eastwest --context ${context} --generate > ew-gateway-${cluster}.yaml kubectl apply -f ew-gateway-${cluster}.yaml --context ${context} } create_ew_gateway_lb ${context1} ${cluster1} create_ew_gateway_lb ${context2} ${cluster2}
Create the east-west gateway in both clusters. Note that the gateway must still be created with a stable internal IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.
- Solo distribution of istioctl: For more information about this command, see the CLI reference.
  function create_ew_gateway_nodeport() { context=${1:?context} cluster=${2:?cluster} kubectl create namespace istio-eastwest --context ${context} istioctl multicluster expose --namespace istio-eastwest --context ${context} --generate > ew-gateway-${cluster}.yaml kubectl apply -f ew-gateway-${cluster}.yaml --context ${context} kubectl annotate gateway istio-eastwest -n istio-eastwest peering.solo.io/data-plane-service-type=NodePort --context ${context} } create_ew_gateway_nodeport ${context1} ${cluster1} create_ew_gateway_nodeport ${context2} ${cluster2}

Verify that the east-west gateway is successfully deployed in both clusters.

kubectl get svc -n istio-eastwest --context ${context1}
kubectl get svc -n istio-eastwest --context ${context2}

Example output:

NAME             TYPE           CLUSTER-IP       EXTERNAL-IP             PORT(S)                                           AGE
istio-eastwest   LoadBalancer   172.20.205.104   <external_address>      15021:31655/TCP,15008:32699/TCP,15012:32166/TCP   55s
NAME             TYPE           CLUSTER-IP       EXTERNAL-IP             PORT(S)                                           AGE
istio-eastwest   LoadBalancer   172.20.21.117    <external_address>      15021:30324/TCP,15008:31875/TCP,15012:31050/TCP   77s

Link clusters

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

Optional: Before you link clusters, you can check the individual readiness of each cluster for linking by running the istioctl multicluster check --precheck command. For more information about this command, see the CLI reference. If any checks fail, run the command with --verbose, and see Validate your multicluster setup.
```
istioctl multicluster check --precheck --contexts="$context1,$context2"
```
Before continuing to the next step, make sure that the following checks pass as expected:
✅ Relevant environment variables on istiod are supported.
✅ The license in use by istiod supports multicluster.
✅ All istiod, ztunnel, and east-west gateway pods are healthy.
✅ The east-west gateway is programmed.

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

In the Solo distribution of Istio 1.29 or later, you can use the peering Helm chart to link your clusters.

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 ${context1} -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
export CLUSTER2_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context ${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"

Link the clusters by creating Helm releases in each cluster to represent the other clusters. In each cluster where you create Helm releases, a Gateway resource is created that uses the istio-remote GatewayClass. This class allows the gateway to connect to other clusters by using the addresses of the east-west gateways.

Be sure to update the region, and optionally zone, of each cluster.
If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, change the preferredDataplaneServiceType to nodeport. This automatically configures the peering gateways for NodePort-based cross-cluster traffic. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.
The following example depicts a bi-directional setup. In an asymmetrical setup, you create Helm releases to only represent the directionality you want to allow.

helm upgrade -i peering-remote oci://${HELM_REPO}/peering \
  --version ${ISTIO_IMAGE} \
  --namespace istio-eastwest \
  --kube-context ${context1} \
  -f - <<EOF
remote:
  create: true
  items:
    # Remote peer configuration for cluster2
    - name: istio-remote-peer-${cluster2}
      cluster: ${cluster2}
      network: ${cluster2}
      # Change to "Hostname" if using hostname
      addressType: IPAddress
      address: ${CLUSTER2_EW_ADDRESS}
      # Change to "nodeport" if using NodePorts
      preferredDataplaneServiceType: loadbalancer
      trustDomain: cluster.local
      region: "<cluster2_region>"
      # Uncomment as needed
      # zone: "<cluster2_zone>"
EOF
helm upgrade -i peering-remote oci://${HELM_REPO}/peering \
  --version ${ISTIO_IMAGE} \
  --namespace istio-eastwest \
  --kube-context ${context2} \
  -f - <<EOF
remote:
  create: true
  items:
    # Remote peer configuration for cluster1
    - name: istio-remote-peer-${cluster1}
      cluster: ${cluster1}
      network: ${cluster1}
      # Change to "Hostname" if using hostname
      addressType: IPAddress
      address: ${CLUSTER1_EW_ADDRESS}
      # Change to "nodeport" if using NodePorts
      preferredDataplaneServiceType: loadbalancer
      trustDomain: cluster.local
      region: "<cluster1_region>"
      # Uncomment as needed
      # zone: "<cluster1_zone>"
EOF

Use the istioctl multicluster link command to quickly link clusters.

Verify that the contexts for the clusters that you want to include in the multicluster mesh are listed in your kubeconfig file, which is required for the istioctl multicluster link command. If you do not have access to the kubeconfig files, use the declarative resources tab.
```
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 kubectl config view --flatten
Using the names of the cluster contexts, link the clusters so that they can communicate. To take a look at the Gateway resources that this command creates, you can include the --generate flag in the command. For more information about this command, see the CLI reference.
- 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" ```<pre><code> If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, use the `--preferred-data-plane-service-type nodeport` flag when linking clusters. This automatically configures the peering gateways for NodePort-based cross-cluster traffic. For more information about NodePort peering considerations and requirements, see [Cross-cluster traffic addresses](#cross-cluster-traffic-addresses).

istioctl multicluster link --namespace istio-eastwest --contexts=&quot;$context1,$context2&quot; --preferred-data-plane-service-type nodeport

 Example output for two clusters:
 ```
 Gateway istio-eastwest/istio-remote-peer-cluster1 applied to cluster "cluster2" pointing to cluster "cluster1" (network "cluster1")
 Gateway istio-eastwest/istio-remote-peer-cluster2 applied to cluster "cluster1" pointing to cluster "cluster2" (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.
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 ${context1} --to ${context2}
```<pre><code> If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, use the `--preferred-data-plane-service-type nodeport` flag when linking clusters. This automatically configures the peering gateways for NodePort-based cross-cluster traffic. For more information about NodePort peering considerations and requirements, see [Cross-cluster traffic addresses](#cross-cluster-traffic-addresses).
```

istioctl multicluster link --namespace istio-eastwest --from ${context1} --to ${context2} --preferred-data-plane-service-type nodeport

 Example output:
 ```
 Gateway istio-eastwest/istio-remote-peer-cluster2 applied to cluster "cluster1" pointing to cluster "cluster2" (network "cluster2")
 ```

Link the clusters by declaratively creating istio-remote peer gateways.

Bi-directional: 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.

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 ${context1} -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
export CLUSTER2_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context ${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"

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 optionally 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. Additionally, you can comment out the HBONE listener in each gateway, because traffic is routed through the NodePort directly. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.

kubectl apply --context ${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: ${cluster2}
    # Uncomment for NodePort-based cross-cluster traffic
    # peering.solo.io/preferred-data-plane-service-type: NodePort
  labels:
    topology.istio.io/network: ${cluster2}
    topology.kubernetes.io/region: "<cluster2_region>"
    # Uncomment as needed
    # topology.kubernetes.io/zone: "<cluster2_zone>"
  name: istio-remote-peer-${cluster2}
  namespace: istio-eastwest
spec:
  addresses:
  # Change to 'type: Hostname' as needed, such as for AWS hostnames
  - 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 ${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: ${cluster1}
    # Uncomment for NodePort-based cross-cluster traffic
    # peering.solo.io/preferred-data-plane-service-type: NodePort
  labels:
    topology.istio.io/network: ${cluster1}
    topology.kubernetes.io/region: "<cluster1_region>"
    # Uncomment as needed
    # topology.kubernetes.io/zone: "<cluster1_zone>"
  name: istio-remote-peer-${cluster1}
  namespace: istio-eastwest
spec:
  addresses:
  # Change to 'type: Hostname' as needed, such as for AWS hostnames
  - 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: 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.

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 ${context2} -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")

echo "Cluster2 east-west gateway: $CLUSTER2_EW_ADDRESS"

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 optionally 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. Additionally, you can comment out the HBONE listener in each gateway, because traffic is routed through the NodePort directly. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.

kubectl apply --context ${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: ${cluster2}
    # Uncomment for NodePort-based cross-cluster traffic
    # peering.solo.io/preferred-data-plane-service-type: NodePort
  labels:
    topology.istio.io/network: ${cluster2}
    topology.kubernetes.io/region: "<cluster2_region>"
    # Uncomment as needed
    # topology.kubernetes.io/zone: "<cluster2_zone>"
  name: istio-remote-peer-${cluster2}
  namespace: istio-eastwest
spec:
  addresses:
  # Change to 'type: Hostname' as needed, such as for AWS hostnames
  - 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

Verify that peer linking was successful by running the istioctl multicluster check command. If any checks fail, run the command with --verbose, and see Validate your multicluster setup.

istioctl multicluster check --contexts="$context1,$context2"

In this example output, the remote peer gateways are successfully connected, and all other checks passed successfully. No global services exist because no app services are exposed across clusters in the multicluster mesh yet.

=== Cluster: cluster1 ===
✅ Incompatible Environment Variable Check: all relevant environment variables are valid
✅ License Check: license is valid for multicluster
✅ CNI DNS Capture Check: AMBIENT_DNS_CAPTURE is enabled
✅ Pod Check (istiod): all pods healthy
✅ Pod Check (ztunnel): all pods healthy
✅ Pod Check (eastwest gateway istio-eastwest/istio-eastwest): all pods healthy
✅ Gateway Check: all eastwest gateways programmed
     ✅ istio-eastwest/istio-eastwest available at aab8471c7fcfa4a3c82f2d217b015d97-396238517.us-east-1.elb.amazonaws.com
✅ Peers Check: all clusters connected
     ✅ Connected to gloo-gateway-docs-mgt via ab46aa29a49914da789a6d5422aca279-541415195.us-east-2.elb.amazonaws.com
ℹ️  Shared Services Check: no globally shared services found
====== 

=== Cluster: cluster2 ===
✅ Incompatible Environment Variable Check: all relevant environment variables are valid
✅ License Check: license is valid for multicluster
✅ CNI DNS Capture Check: AMBIENT_DNS_CAPTURE is enabled
✅ Pod Check (istiod): all pods healthy
✅ Pod Check (ztunnel): all pods healthy
✅ Pod Check (eastwest gateway istio-eastwest/istio-eastwest): all pods healthy
✅ Gateway Check: all eastwest gateways programmed
     ✅ istio-eastwest/istio-eastwest available at ab46aa29a49914da789a6d5422aca279-541415195.us-east-2.elb.amazonaws.com
✅ Peers Check: all clusters connected
     ✅ Connected to gloo-mesh-core-docs-mgt via aab8471c7fcfa4a3c82f2d217b015d97-396238517.us-east-1.elb.amazonaws.com
ℹ️  Shared Services Check: no globally shared services found
====== 

✅ Intermediate Certs Compatibility Check: all clusters have compatible intermediate certificates
✅ Network Configuration Check: all network configurations are valid
✅ Stale Workloads Check: skipped (flat network not detected)

Optional: Verify that the istiod control plane for each peered cluster is included in each cluster’s proxy status list.

istioctl proxy-status --context ${context1}
istioctl proxy-status --context ${context2}

Example output for cluster1, in which you can verify that the istiod control plane for cluster2 is listed:

NAME                                               CLUSTER          ISTIOD                      VERSION              SUBSCRIBED TYPES
istio-eastwest-67fd5679dc-fhsxs.istio-eastwest     cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)
istiod-6bc6765484-5bbhd.istio-system               cluster2         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     3 (FSDS,SGDS,WDS)
ztunnel-5f8rb.kube-system                          cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)
ztunnel-f96kh.kube-system                          cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)
ztunnel-vtj4f.kube-system                          cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)

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

Option 2: Upgrade and link existing ambient meshes

Upgrade your existing ambient meshes installed with Helm and link them to create a multicluster ambient mesh.

Set up tools

Set your Enterprise level license for Solo Enterprise for Istio 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. Note that you might have previously saved this key in another variable, such as ${SOLO_LICENSE_KEY} or ${GLOO_MESH_LICENSE_KEY}.
```
export SOLO_ISTIO_LICENSE_KEY=<enterprise_license_key>
```
Choose the version of Istio that you want to install or upgrade to by reviewing the supported versions.

Save the Solo distribution of Istio version.

export ISTIO_VERSION=1.28.5
export ISTIO_IMAGE=${ISTIO_VERSION}-solo

Save the 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}
```
Get the Solo distribution of Istio binary and install istioctl, which you use for multicluster linking and gateway commands. This script automatically detects your OS and architecture, downloads the appropriate Solo distribution of Istio binary, and verifies the installation.
```
bash <(curl -sSfL https://raw.githubusercontent.com/solo-io/doc-examples/main/istio/install-istioctl.sh)
export PATH=${HOME}/.istioctl/bin:${PATH}
```
Save the names and kubeconfig contexts of each cluster. This guide uses two clusters as an example. To add more clusters to the multicluster setup, include them in the arrays.
```
export cluster1=<cluster1_name>
export context1=<cluster1_context>
export cluster2=<cluster2_name>
export context2=<cluster2_context>
```

Create a shared root of trust

For demo installations, you can run the following function to quickly generate and plug in the certificates and key for the Istio CA:

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 ${context1} ${cluster1}
create_cacerts_secret ${context2} ${cluster2}

cd ../..

Upgrade settings

In each cluster, update the ambient mesh components for multicluster, and create an east-west gateway so that traffic requests can be routed cross-cluster.

Get the current values for the istiod Helm release in both clusters.

function get_istiod_values() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm get values --kube-context ${context} istiod -n istio-system -o yaml > istiod-${cluster}.yaml
}

get_istiod_values ${context1} ${cluster1}
get_istiod_values ${context2} ${cluster2}

Update your Helm release with the following multicluster values in both clusters. If you must update the Istio minor version, include the --set global.tag=${ISTIO_IMAGE} and --set global.hub=${REPO} flags too.

If you prefer to specify your license secret instead of an inline value, you can include --set license.secretRef.name=<name> and --set license.secretRef.namespace=<namespace>.

function upgrade_istiod() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade istiod oci://${HELM_REPO}/istiod \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f istiod-${cluster}.yaml \
  --set env.PILOT_ENABLE_IP_AUTOALLOCATE="true" \
  --set env.DISABLE_LEGACY_MULTICLUSTER="true" \
  --set env.PILOT_SKIP_VALIDATE_TRUST_DOMAIN="true" \
  --set global.multiCluster.clusterName=${cluster} \
  --set global.network=${cluster} \
  --set global.trustDomain="${cluster}.local" \
  --set platforms.peering.enabled=true \
  --set license.value=${SOLO_ISTIO_LICENSE_KEY}
}

upgrade_istiod ${context1} ${cluster1}
upgrade_istiod ${context2} ${cluster2}

If you prefer to specify your license secret instead of an inline value, you can include --set license.secretRef.name=<name> and --set license.secretRef.namespace=<namespace>.

function upgrade_istiod() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade istiod oci://${HELM_REPO}/istiod \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f istiod-${cluster}.yaml \
  --set env.PILOT_ENABLE_IP_AUTOALLOCATE="true" \
  --set env.DISABLE_LEGACY_MULTICLUSTER="true" \
  --set env.PILOT_SKIP_VALIDATE_TRUST_DOMAIN="true" \
  --set global.multiCluster.clusterName=${cluster} \
  --set global.network=${cluster} \
  --set global.platform=openshift \
  --set global.trustDomain="${cluster}.local" \
  --set platforms.peering.enabled=true \
  --set license.value=${SOLO_ISTIO_LICENSE_KEY}
}

upgrade_istiod ${context1} ${cluster1}
upgrade_istiod ${context2} ${cluster2}

Verify that the istiod pods are successfully restarted in both clusters. Note that it might take a few seconds for the pods to become available.

kubectl get pods --context ${context1} -n istio-system | grep istiod
kubectl get pods --context ${context2} -n istio-system | grep istiod

Example output:

istiod-b84c55cff-tllfr   1/1     Running   0          58s

Optional: Check the istiod logs in both clusters to verify that the certificate you generated earlier is picked up by istiod.

kubectl logs deploy/istiod -n istio-system --context ${context1} | grep x509
kubectl logs deploy/istiod -n istio-system --context ${context2} | grep x509

Example output:

2025-12-16T22:59:06.783901Z     info    x509 cert - Issuer: "CN=Intermediate CA,O=Istio,L=cluster-1", Subject: "", SN: def320623729b8370172413749143836, NotBefore: "2025-12-16T22:57:06Z", NotAfter: "2035-12-14T22:59:06Z"
2025-12-16T22:59:06.783937Z     info    x509 cert - Issuer: "CN=Root CA,O=Istio", Subject: "CN=Intermediate CA,O=Istio,L=cluster-1", SN: 452d45254328667ccf8434c64c79fe789612bb5a, NotBefore: "2025-12-16T22:54:30Z", NotAfter: "2035-12-14T22:54:30Z"
2025-12-16T22:59:06.783966Z     info    x509 cert - Issuer: "CN=Root CA,O=Istio", Subject: "CN=Root CA,O=Istio", SN: 38dad68e56ab8c506ae07454801f65b134bd9580, NotBefore: "2025-12-16T22:54:30Z", NotAfter: "2035-12-14T22:54:30Z"

Get the current values for the ztunnel Helm release in both clusters.

function get_ztunnel_values() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm get values ztunnel --kube-context ${context} -n istio-system -o yaml > ztunnel-${cluster}.yaml
}

get_ztunnel_values ${context1} ${cluster1}
get_ztunnel_values ${context2} ${cluster2}

function get_ztunnel_values() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm get values ztunnel --kube-context ${context} -n kube-system -o yaml > ztunnel-${cluster}.yaml
}

get_ztunnel_values ${context1} ${cluster1}
get_ztunnel_values ${context2} ${cluster2}

Update your Helm release with the following multicluster values in both clusters. If you must update the Istio minor version, include the --set tag=${ISTIO_IMAGE} and --set hub=${REPO} flags too.

function upgrade_ztunnel() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade ztunnel oci://${HELM_REPO}/ztunnel \
  -n istio-system \
  --version ${ISTIO_IMAGE} \
  --kube-context ${context} \
  -f ztunnel-${cluster}.yaml \
  --set env.SKIP_VALIDATE_TRUST_DOMAIN="true" \
  --set multiCluster.clusterName=${cluster} \
  --set network=${cluster}
}

upgrade_ztunnel ${context1} ${cluster1}
upgrade_ztunnel ${context2} ${cluster2}

function upgrade_ztunnel() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade ztunnel oci://${HELM_REPO}/ztunnel \
  -n kube-system \
  --version ${ISTIO_IMAGE} \
  --kube-context ${context} \
  -f ztunnel-${cluster}.yaml \
  --set env.SKIP_VALIDATE_TRUST_DOMAIN="true" \
  --set multiCluster.clusterName=${cluster} \
  --set network=${cluster}
}

upgrade_ztunnel ${context1} ${cluster1}
upgrade_ztunnel ${context2} ${cluster2}

Verify that the ztunnel pods are successfully installed in both clusters. Because the ztunnel is deployed as a daemon set, the number of pods equals the number of nodes in your cluster. Note that it might take a few seconds for the pods to become available.

kubectl get pods -A --context ${context1} | grep ztunnel
kubectl get pods -A --context ${context2} | grep ztunnel

Example output for one cluster:

ztunnel-tvtzn             1/1     Running   0          7s
ztunnel-vtpjm             1/1     Running   0          4s
ztunnel-hllxg             1/1     Running   0          4s

Label the istio-system namespace with the clusters’ network names, which you previously set to each cluster name in the global.network field of the istiod installations. The ambient control plane uses this label internally to group pods that exist in the same L3 network.
```
kubectl label namespace istio-system --context ${context1} topology.istio.io/network=${cluster1}
kubectl label namespace istio-system --context ${context2} topology.istio.io/network=${cluster2}
```
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.
Create the east-west gateway in both clusters. Cross-cluster traffic though this gateway resolves to the LoadBalancer address. For customization options, see the gateway guide in the Istio docs.
- Solo distribution of istioctl: For more information about this command, see the CLI reference.
  function create_ew_gateway_lb() { context=${1:?context} cluster=${2:?cluster} kubectl create namespace istio-eastwest --context ${context} istioctl multicluster expose --namespace istio-eastwest --context ${context} --generate > ew-gateway-${cluster}.yaml kubectl apply -f ew-gateway-${cluster}.yaml --context ${context} } create_ew_gateway_lb ${context1} ${cluster1} create_ew_gateway_lb ${context2} ${cluster2}
Create the east-west gateway in both clusters. Note that the gateway must still be created with a stable internal IP address, which is required for xDS communication with the istiod control plane in each cluster. NodePort peering is used for data plane communication, in that requests to services resolve to the NodePort instead of the gateway’s stable IP address. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.
- Solo distribution of istioctl: For more information about this command, see the CLI reference.
  function create_ew_gateway_nodeport() { context=${1:?context} cluster=${2:?cluster} kubectl create namespace istio-eastwest --context ${context} istioctl multicluster expose --namespace istio-eastwest --context ${context} --generate > ew-gateway-${cluster}.yaml kubectl apply -f ew-gateway-${cluster}.yaml --context ${context} kubectl annotate gateway istio-eastwest -n istio-eastwest peering.solo.io/data-plane-service-type=NodePort --context ${context} } create_ew_gateway_nodeport ${context1} ${cluster1} create_ew_gateway_nodeport ${context2} ${cluster2}

Verify that the east-west gateway is successfully deployed in both clusters.

kubectl get svc -n istio-eastwest --context ${context1}
kubectl get svc -n istio-eastwest --context ${context2}

Example output:

NAME             TYPE           CLUSTER-IP       EXTERNAL-IP             PORT(S)                                           AGE
istio-eastwest   LoadBalancer   172.20.205.104   <external_address>      15021:31655/TCP,15008:32699/TCP,15012:32166/TCP   55s
NAME             TYPE           CLUSTER-IP       EXTERNAL-IP             PORT(S)                                           AGE
istio-eastwest   LoadBalancer   172.20.21.117    <external_address>      15021:30324/TCP,15008:31875/TCP,15012:31050/TCP   77s

Link clusters

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

Optional: Before you link clusters, you can check the individual readiness of each cluster for linking by running the istioctl multicluster check --precheck command. For more information about this command, see the CLI reference. If any checks fail, run the command with --verbose, and see Validate your multicluster setup.
```
istioctl multicluster check --precheck --contexts="$context1,$context2"
```
Before continuing to the next step, make sure that the following checks pass as expected:
✅ Relevant environment variables on istiod are supported.
✅ The license in use by istiod supports multicluster.
✅ All istiod, ztunnel, and east-west gateway pods are healthy.
✅ The east-west gateway is programmed.

In the Solo distribution of Istio 1.29 or later, you can use the peering Helm chart to link your clusters.

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 ${context1} -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
export CLUSTER2_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context ${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"

Be sure to update the region, and optionally zone, of each cluster.
If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, change the preferredDataplaneServiceType to nodeport. This automatically configures the peering gateways for NodePort-based cross-cluster traffic. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.
The following example depicts a bi-directional setup. In an asymmetrical setup, you create Helm releases to only represent the directionality you want to allow.

helm upgrade -i peering-remote oci://${HELM_REPO}/peering \
  --version ${ISTIO_IMAGE} \
  --namespace istio-eastwest \
  --kube-context ${context1} \
  -f - <<EOF
remote:
  create: true
  items:
    # Remote peer configuration for cluster2
    - name: istio-remote-peer-${cluster2}
      cluster: ${cluster2}
      network: ${cluster2}
      # Change to "Hostname" if using hostname
      addressType: IPAddress
      address: ${CLUSTER2_EW_ADDRESS}
      # Change to "nodeport" if using NodePorts
      preferredDataplaneServiceType: loadbalancer
      trustDomain: cluster.local
      region: "<cluster2_region>"
      # Uncomment as needed
      # zone: "<cluster2_zone>"
EOF
helm upgrade -i peering-remote oci://${HELM_REPO}/peering \
  --version ${ISTIO_IMAGE} \
  --namespace istio-eastwest \
  --kube-context ${context2} \
  -f - <<EOF
remote:
  create: true
  items:
    # Remote peer configuration for cluster1
    - name: istio-remote-peer-${cluster1}
      cluster: ${cluster1}
      network: ${cluster1}
      # Change to "Hostname" if using hostname
      addressType: IPAddress
      address: ${CLUSTER1_EW_ADDRESS}
      # Change to "nodeport" if using NodePorts
      preferredDataplaneServiceType: loadbalancer
      trustDomain: cluster.local
      region: "<cluster1_region>"
      # Uncomment as needed
      # zone: "<cluster1_zone>"
EOF

Use the istioctl multicluster link command to quickly link clusters.

Verify that the contexts for the clusters that you want to include in the multicluster mesh are listed in your kubeconfig file, which is required for the istioctl multicluster link command. If you do not have access to the kubeconfig files, use the declarative resources tab.
```
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 kubectl config view --flatten
Using the names of the cluster contexts, link the clusters so that they can communicate. To take a look at the Gateway resources that this command creates, you can include the --generate flag in the command. For more information about this command, see the CLI reference.
- 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" ```<pre><code> If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, use the `--preferred-data-plane-service-type nodeport` flag when linking clusters. This automatically configures the peering gateways for NodePort-based cross-cluster traffic. For more information about NodePort peering considerations and requirements, see [Cross-cluster traffic addresses](#cross-cluster-traffic-addresses).

istioctl multicluster link --namespace istio-eastwest --contexts=&quot;$context1,$context2&quot; --preferred-data-plane-service-type nodeport

 Example output for two clusters:
 ```
 Gateway istio-eastwest/istio-remote-peer-cluster1 applied to cluster "cluster2" pointing to cluster "cluster1" (network "cluster1")
 Gateway istio-eastwest/istio-remote-peer-cluster2 applied to cluster "cluster1" pointing to cluster "cluster2" (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.
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 ${context1} --to ${context2}
```<pre><code> If you want to use NodePorts instead of the gateway LoadBalancer IP address for cross-cluster traffic, use the `--preferred-data-plane-service-type nodeport` flag when linking clusters. This automatically configures the peering gateways for NodePort-based cross-cluster traffic. For more information about NodePort peering considerations and requirements, see [Cross-cluster traffic addresses](#cross-cluster-traffic-addresses).
```

istioctl multicluster link --namespace istio-eastwest --from ${context1} --to ${context2} --preferred-data-plane-service-type nodeport

 Example output:
 ```
 Gateway istio-eastwest/istio-remote-peer-cluster2 applied to cluster "cluster1" pointing to cluster "cluster2" (network "cluster2")
 ```

Link the clusters by declaratively creating istio-remote peer gateways.

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 ${context1} -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
export CLUSTER2_EW_ADDRESS=$(kubectl get svc -n istio-eastwest istio-eastwest --context ${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"

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 optionally 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. Additionally, you can comment out the HBONE listener in each gateway, because traffic is routed through the NodePort directly. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.

kubectl apply --context ${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: ${cluster2}
    # Uncomment for NodePort-based cross-cluster traffic
    # peering.solo.io/preferred-data-plane-service-type: NodePort
  labels:
    topology.istio.io/network: ${cluster2}
    topology.kubernetes.io/region: "<cluster2_region>"
    # Uncomment as needed
    # topology.kubernetes.io/zone: "<cluster2_zone>"
  name: istio-remote-peer-${cluster2}
  namespace: istio-eastwest
spec:
  addresses:
  # Change to 'type: Hostname' as needed, such as for AWS hostnames
  - 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 ${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: ${cluster1}
    # Uncomment for NodePort-based cross-cluster traffic
    # peering.solo.io/preferred-data-plane-service-type: NodePort
  labels:
    topology.istio.io/network: ${cluster1}
    topology.kubernetes.io/region: "<cluster1_region>"
    # Uncomment as needed
    # topology.kubernetes.io/zone: "<cluster1_zone>"
  name: istio-remote-peer-${cluster1}
  namespace: istio-eastwest
spec:
  addresses:
  # Change to 'type: Hostname' as needed, such as for AWS hostnames
  - 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

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 ${context2} -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")

echo "Cluster2 east-west gateway: $CLUSTER2_EW_ADDRESS"

In the labels section, be sure to update the locality labels according to the region, and optionally 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. Additionally, you can comment out the HBONE listener in each gateway, because traffic is routed through the NodePort directly. For more information about NodePort peering considerations and requirements, see Cross-cluster traffic addresses.

kubectl apply --context ${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: ${cluster2}
    # Uncomment for NodePort-based cross-cluster traffic
    # peering.solo.io/preferred-data-plane-service-type: NodePort
  labels:
    topology.istio.io/network: ${cluster2}
    topology.kubernetes.io/region: "<cluster2_region>"
    # Uncomment as needed
    # topology.kubernetes.io/zone: "<cluster2_zone>"
  name: istio-remote-peer-${cluster2}
  namespace: istio-eastwest
spec:
  addresses:
  # Change to 'type: Hostname' as needed, such as for AWS hostnames
  - 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

Verify that peer linking was successful by running the istioctl multicluster check command. If any checks fail, run the command with --verbose, and see Validate your multicluster setup.

istioctl multicluster check --contexts="$context1,$context2"

=== Cluster: cluster1 ===
✅ Incompatible Environment Variable Check: all relevant environment variables are valid
✅ License Check: license is valid for multicluster
✅ CNI DNS Capture Check: AMBIENT_DNS_CAPTURE is enabled
✅ Pod Check (istiod): all pods healthy
✅ Pod Check (ztunnel): all pods healthy
✅ Pod Check (eastwest gateway istio-eastwest/istio-eastwest): all pods healthy
✅ Gateway Check: all eastwest gateways programmed
     ✅ istio-eastwest/istio-eastwest available at aab8471c7fcfa4a3c82f2d217b015d97-396238517.us-east-1.elb.amazonaws.com
✅ Peers Check: all clusters connected
     ✅ Connected to gloo-gateway-docs-mgt via ab46aa29a49914da789a6d5422aca279-541415195.us-east-2.elb.amazonaws.com
ℹ️  Shared Services Check: no globally shared services found
====== 

=== Cluster: cluster2 ===
✅ Incompatible Environment Variable Check: all relevant environment variables are valid
✅ License Check: license is valid for multicluster
✅ CNI DNS Capture Check: AMBIENT_DNS_CAPTURE is enabled
✅ Pod Check (istiod): all pods healthy
✅ Pod Check (ztunnel): all pods healthy
✅ Pod Check (eastwest gateway istio-eastwest/istio-eastwest): all pods healthy
✅ Gateway Check: all eastwest gateways programmed
     ✅ istio-eastwest/istio-eastwest available at ab46aa29a49914da789a6d5422aca279-541415195.us-east-2.elb.amazonaws.com
✅ Peers Check: all clusters connected
     ✅ Connected to gloo-mesh-core-docs-mgt via aab8471c7fcfa4a3c82f2d217b015d97-396238517.us-east-1.elb.amazonaws.com
ℹ️  Shared Services Check: no globally shared services found
====== 

✅ Intermediate Certs Compatibility Check: all clusters have compatible intermediate certificates
✅ Network Configuration Check: all network configurations are valid
✅ Stale Workloads Check: skipped (flat network not detected)

Optional: Verify that the istiod control plane for each peered cluster is included in each cluster’s proxy status list.

istioctl proxy-status --context ${context1}
istioctl proxy-status --context ${context2}

Example output for cluster1, in which you can verify that the istiod control plane for cluster2 is listed:

NAME                                               CLUSTER          ISTIOD                      VERSION              SUBSCRIBED TYPES
istio-eastwest-67fd5679dc-fhsxs.istio-eastwest     cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)
istiod-6bc6765484-5bbhd.istio-system               cluster2         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     3 (FSDS,SGDS,WDS)
ztunnel-5f8rb.kube-system                          cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)
ztunnel-f96kh.kube-system                          cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)
ztunnel-vtj4f.kube-system                          cluster1         istiod-7b7c9cc4c6-bdm9c     1.28.5-solo-fips     2 (WADS,WDS)

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

Option 3: Automatically link clusters (beta)

In each cluster, use Helm to create the ambient 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.

Automated multicluster peering is a beta feature. Do not use this feature in production deployments. For more information, see Solo feature maturity.

Review the following considerations:

Multicluster mesh capabilities require an Enterprise level license for Solo Enterprise for Istio. If you do not have one, [contact an account representative](https://www.solo.io/company/contact).
Automated peering requires Istio to be installed in the same cluster that the Gloo management plane is deployed to.

Set up tools

Set your Enterprise level license for Solo Enterprise for Istio 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. Note that you might have previously saved this key in another variable, such as ${SOLO_LICENSE_KEY} or ${GLOO_MESH_LICENSE_KEY}.
```
export SOLO_ISTIO_LICENSE_KEY=<enterprise_license_key>
```
Choose the version of Istio that you want to install or upgrade to by reviewing the supported versions.

Save the Solo distribution of Istio version.

export ISTIO_VERSION=1.28.5
export ISTIO_IMAGE=${ISTIO_VERSION}-solo

Save the 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}
```
Get the Solo distribution of Istio binary and install istioctl, which you use for multicluster linking and gateway commands. This script automatically detects your OS and architecture, downloads the appropriate Solo distribution of Istio binary, and verifies the installation.
```
bash <(curl -sSfL https://raw.githubusercontent.com/solo-io/doc-examples/main/istio/install-istioctl.sh)
export PATH=${HOME}/.istioctl/bin:${PATH}
```
Save the names and kubeconfig contexts of each cluster. This guide uses two clusters as an example. To add more clusters to the multicluster setup, include them in the arrays.
```
export cluster1=<cluster1_name>
export context1=<cluster1_context>
export cluster2=<cluster2_name>
export context2=<cluster2_context>
```

Enable automatic peering of clusters

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

These steps assume you already installed Solo Enterprise for Istio, and show you how to upgrade your Helm install values. If you have not yet installed Solo Enterprise for Istio, follow the steps in Set up multicluster management.

In the cluster where you installed the management plane, upgrade your gloo-platform-crds Helm release to include the following settings.

helm get values gloo-platform-crds -n gloo-mesh -o yaml --kube-context ${context1} > mgmt-crds.yaml
helm upgrade gloo-platform-crds gloo-platform/gloo-platform-crds \
  --kube-context ${context1} \
  --namespace gloo-mesh \
  -f mgmt-crds.yaml \
  --set featureGates.ConfigDistribution=true \
  --set installEnterpriseCrds=true

In the cluster where you installed the management plane, upgrade your gloo-platform Helm release to include the following settings.

helm get values gloo-platform -n gloo-mesh -o yaml --kube-context ${context1} > mgmt-plane.yaml
helm upgrade gloo-platform gloo-platform/gloo-platform \
  --kube-context ${context1} \
  --namespace gloo-mesh \
  -f mgmt-plane.yaml \
  --set featureGates.ConfigDistribution=true

In each connected cluster, upgrade your gloo-platform-crds Helm release 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 ${context2} > crds.yaml
helm upgrade gloo-platform-crds gloo-platform/gloo-platform-crds \
  --kube-context ${context2} \
  --namespace gloo-mesh \
  -f crds.yaml \
  --set installEnterpriseCrds=true

Create a shared root of trust

For demo installations, you can run the following function to quickly generate and plug in the certificates and key for the Istio CA:

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 ${context1} ${cluster1}
create_cacerts_secret ${context2} ${cluster2}

cd ../..

Deploy ambient components

kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.4.0/standard-install.yaml --context ${context1}
kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.4.0/standard-install.yaml --context ${context2}

Install the base chart, which contains the CRDs and cluster roles required to set up Istio, in both clusters.

function install_base() {
  context=${1:?context}
  helm upgrade --install istio-base oci://${HELM_REPO}/base \
  --namespace istio-system \
  --create-namespace \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
defaultRevision: ""
profile: ambient
EOF
}

install_base ${context1}
install_base ${context2}

function install_base() {
  context=${1:?context}
  helm upgrade --install istio-base oci://${HELM_REPO}/base \
  --namespace istio-system \
  --create-namespace \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
defaultRevision: ""
profile: ambient
global:
  platform: openshift
EOF
}

install_base ${context1}
install_base ${context2}

You can optionally verify that the CRDs are successfully installed in both clusters.

kubectl get crds -l app.kubernetes.io/instance=istio-base --kube-context ${context1}
kubectl get crds -l app.kubernetes.io/instance=istio-base --kube-context ${context2}

Example output:

NAME                                       CREATED AT
authorizationpolicies.security.istio.io    2025-12-16T22:56:00Z
destinationrules.networking.istio.io       2025-12-16T22:56:00Z
envoyfilters.networking.istio.io           2025-12-16T22:56:00Z
gateways.networking.istio.io               2025-12-16T22:56:00Z
peerauthentications.security.istio.io      2025-12-16T22:56:00Z
proxyconfigs.networking.istio.io           2025-12-16T22:56:00Z
requestauthentications.security.istio.io   2025-12-16T22:56:00Z
segments.admin.solo.io                     2025-12-16T22:56:00Z
serviceentries.networking.istio.io         2025-12-16T22:56:00Z
sidecars.networking.istio.io               2025-12-16T22:56:00Z
telemetries.telemetry.istio.io             2025-12-16T22:56:00Z
virtualservices.networking.istio.io        2025-12-16T22:56:00Z
wasmplugins.extensions.istio.io            2025-12-16T22:56:00Z
workloadentries.networking.istio.io        2025-12-16T22:56:00Z
workloadgroups.networking.istio.io         2025-12-16T22:56:00Z

Create the istiod control plane in both clusters.

function install_istiod() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade --install istiod oci://${HELM_REPO}/istiod \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
env:
  # Enables automatic creation of remote peer gateways
  PEERING_AUTOMATIC_LOCAL_GATEWAY: "true"
  # Assigns IP addresses to multicluster services
  PILOT_ENABLE_IP_AUTOALLOCATE: "true"
  # Disable community Istio multicluster mechanisms
  DISABLE_LEGACY_MULTICLUSTER: "true"
  # Required when meshConfig.trustDomain is set
  PILOT_SKIP_VALIDATE_TRUST_DOMAIN: "true"
global:
  hub: ${REPO}
  multiCluster:
    clusterName: ${cluster}
  network: ${cluster}
  proxy:
    clusterDomain: cluster.local
  tag: ${ISTIO_IMAGE}
meshConfig:
  accessLogFile: /dev/stdout
  defaultConfig:
    proxyMetadata:
      ISTIO_META_DNS_CAPTURE: "true"
  # Assign each cluster a unique trust domain to apply policies to specific clusters
  trustDomain: "${cluster}.local"
pilot:
  cni:
    namespace: istio-system
    enabled: true
# Required to enable multicluster support
platforms:
  peering:
    enabled: true
profile: ambient
license:
  value: ${SOLO_ISTIO_LICENSE_KEY}
  # Uncomment if you prefer to specify your license secret
  # instead of an inline value.
  # secretRef:
  #   name:
  #   namespace:
EOF
}

install_istiod ${context1} ${cluster1}
install_istiod ${context2} ${cluster2}

function install_istiod() {
  context=${1:?context}
  cluster=${2:?cluster}
  helm upgrade --install istiod oci://${HELM_REPO}/istiod \
  --namespace istio-system \
  --kube-context ${context} \
  --version ${ISTIO_IMAGE} \
  -f - <<EOF
env:
  # Enables automatic creation of remote peer gateways
  PEERING_AUTOMATIC_LOCAL_GATEWAY: "true"
  # Assigns IP addresses to multicluster services
  PILOT_ENABLE_IP_AUTOALLOCATE: "true"
  # Disable community Istio multicluster mechanisms
  DISABLE_LEGACY_MULTICLUSTER: "true"
  # Required when meshConfig.trustDomain is set
  PILOT_SKIP_VALIDATE_TRUST_DOMAIN: "true"
global:
  hub: ${REPO}
  multiCluster:
    clusterName: ${cluster}
  network: ${cluster}
  platform: openshift
  proxy:
    clusterDomain: cluster.local
  tag: ${ISTIO_IMAGE}
meshConfig:
  accessLogFile: /dev/stdout
  defaultConfig:
    proxyMetadata:
      ISTIO_META_DNS_CAPTURE: "true"
  # Assign each cluster a unique trust domain to apply policies to specific clusters
  trustDomain: "${cluster}.local"
pilot:
  cni:
    namespace: kube-system
    enabled: true
# Required to enable multicluster support
platforms:
  peering:
    enabled: true
profile: ambient
license:
  value: ${SOLO_ISTIO_LICENSE_KEY}
  # Uncomment if you prefer to specify your license secret
  # instead of an inline value.
  # secretRef:
  #   name:
  #   namespace:
EOF
}

install_istiod ${context1} ${cluster1}
install_istiod ${context2} ${cluster2}

Helm

Overview

Considerations

License requirements

Version requirements

Platform requirements

Revision and canary upgrade limitations

Cross-cluster traffic addresses

Migrating from multicluster community Istio

Multicluster setup method

Option 1: Install and link new ambient meshes

Set up tools

Create a shared root of trust

Deploy ambient components

Link clusters

Option 2: Upgrade and link existing ambient meshes

Set up tools

Create a shared root of trust

Upgrade settings

Link clusters

Option 3: Automatically link clusters (beta)

Set up tools

Enable automatic peering of clusters

Create a shared root of trust

Deploy ambient components

Review remote peer gateways

Next

Optional: Validate your multicluster setup

istioctl multicluster check

Further debugging and observability