Attach third-party clusters to Google Cloud (previous generation)

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Anthos attached clusters lets you view your existing Kubernetes clusters in the Google Cloud console along with your Anthos clusters, and enable several Anthos features on them, including centralized configuration control with Anthos Config Management and microservice architecture management with Anthos Service Mesh.

Supported Kubernetes clusters

You can attach any conformant Kubernetes cluster that includes x86 nodes to your fleet and view it in the Google Cloud console with your Anthos clusters.

The following cluster types and versions have been validated by Google. For information on the Anthos features that are supported on attached clusters, see Anthos components and multi-cloud support.

Attached cluster types Kubernetes versions
Red Hat OpenShift Kubernetes Engine (OKE) 4.9, 4.10 1.23, 1.24
Red Hat OpenShift Container Platform (OCP) 4.9, 4.10 1.23, 1.24
Rancher Kubernetes Engine (RKE) 1.3.8 1.23, 1.24
KIND 0.12 1.23, 1.24
K3s 1.20 1.20
K3d 4.4.3 1.20

Before you start

  1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

  2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  3. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.

  4. Enable the Anthos API.

    Enable the API

  5. Install the Google Cloud CLI.

  6. To initialize the gcloud CLI, run the following command: 

    gcloud init
    7.

  7. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  8. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.

  9. Enable the Anthos API.

    Enable the API

  10. Install the Google Cloud CLI.

  11. To initialize the gcloud CLI, run the following command: 

    gcloud init
    12.
  12. Check the fleet registration prerequisites to ensure that you have the relevant permissions and enabled APIs to register a cluster. See the Attached cluster prerequisites section for any special setup steps you may need for your cluster type.

Register attached clusters

You must register all clusters that you want to use with Anthos to your project's fleet. A fleet provides a way to logically group and normalize Kubernetes clusters, making administration of infrastructure easier. Fleet clusters can be browsed and managed together in the Google Cloud console, and many Anthos and Google Cloud components use fleet concepts such as identity sameness and namespace sameness to simplify working with multiple clusters. You can find out much more about fleets and the functionality that they enable in our Fleet management guide.

You are entitled to enable and use Anthos features on these clusters, and you can manage some Anthos features at fleet level from the Anthos Features page. Anthos charges apply only to your registered clusters.

Set up identity

All attached clusters require an identity for the Connect Agent to use when authenticating to Google. If your cluster meets the requirements, you can register it with fleet Workload Identity enabled for authentication. Clusters with this feature enabled use identities from a fleet-wide fleet workload identity pool. You can find out more about how fleet Workload Identity works and the advantages of using it in Use fleet Workload Identity.

If you can't use fleet Workload Identity, registering an attached cluster requires a Google Cloud service account for authentication. We recommend creating a new service account for each cluster you want to attach. To create a service account for a cluster with the appropriate roles, follow the instructions in Creating a Google Cloud service account with gcloud. After you have created your service account, you can use the JSON file with the service account's credentials (key file) to register your cluster, as described in the next section.

Register your cluster

gcloud

Run the following command:

gcloud container fleet memberships register MEMBERSHIP_NAME \
   --context=KUBECONFIG_CONTEXT \
   --kubeconfig=KUBECONFIG_PATH \
   --service-account-key-file=SERVICE_ACCOUNT_KEY_PATH

Replace the following:

  • MEMBERSHIP_NAME: the membership name that you choose and that is used to uniquely represent the cluster being registered to the fleet.
  • SERVICE_ACCOUNT_KEY_PATH: the local filepath to the service account's private key JSON file downloaded as part of Prerequisites. This service account key is stored as a secret named creds-gcp in the gke-connect namespace.
  • KUBECONFIG_CONTEXT: the cluster context of the cluster being registered as it appears in the kubeconfig file. You can get this value from the command line by running kubectl config current-context.
  • KUBECONFIG_PATH: the local filepath where your kubeconfig containing an entry for the cluster being registered is stored. This defaults to $KUBECONFIG if that environment variable is set; otherwise, this defaults to $HOME/.kube/config.

Register an attached cluster with fleet Workload Identity

To register an attached cluster with fleet Workload Identity enabled, run one of the following commands. For more information about which attached cluster types can use this feature and any additional requirements, see Attached cluster prerequisites.

Attach EKS clusters

  1. Get the OIDC provider URL for your cluster and ensure that it is publicly visible. If no provider exists, follow the instructions in Create an IAM OIDC provider for your cluster, and then run the command again.

    aws eks describe-cluster --name MEMBERSHIP_NAME \
 --region AWS_REGION \
 --query "cluster.identity.oidc.issuer" \
 --output text

  2. Run the following command, replacing OIDC_URL with the URL returned by the previous command:

    gcloud container fleet memberships register MEMBERSHIP_NAME \
  --context=KUBECONFIG_CONTEXT \
  --kubeconfig=KUBECONFIG_PATH \
  --enable-workload-identity \
  --public-issuer-url=OIDC_URL

Attach AKS, OpenShift, or other clusters

gcloud container fleet memberships register MEMBERSHIP_NAME \
   --context=KUBECONFIG_CONTEXT \
   --kubeconfig=KUBECONFIG_PATH \
   --enable-workload-identity \
   --has-private-issuer

Console

Generate a registration command

You can use the Google Cloud console to help generate a gcloud registration command to register your cluster (with a service account only).

To register a cluster:

  1. In the Google Cloud console, go to the Anthos Clusters page. This page shows all your registered clusters.

    Go to the Anthos Clusters page

  2. Click Register existing cluster.

  3. Click Add external cluster.

  4. Enter the name of the cluster that you want to register in the Cluster name field.

  5. Optional: Add Google Cloud labels to your cluster.

  6. Click Generate registration command.

  7. In Cloud Shell or wherever you have saved your service account credentials, edit and run the gcloud command that is displayed on the page. You need to specify the following values:

    • The CLUSTER_CONTEXT is the cluster's context as it appears in the kubeconfig file. You can get this value from the command line by running kubectl config current-context.
    • The KUBECONFIG_PATH is the local filepath where your kubeconfig file is stored. This defaults to $KUBECONFIG if that environment variable is set; otherwise, it defaults to $HOME/.kube/config.
    • The LOCAL_KEY_PATH is the path to your service account key file.

    Running this command deploys the Connect Agent in your user cluster. When the Connect Agent connects to Google Cloud and your cluster is registered, a success message is displayed on the page.

  8. Click Set labels, or click Skip if you didn't set any labels.

Enable Anthos features on attached clusters

After you register your clusters, you can enable available Anthos features on them for your applications. These features are supported only on our validated cluster types. You can see the current feature versions supported on these types in Version and upgrade support.

The following guides show you how to enable supported features on your clusters:

For complete documentation sets for all Anthos components, including tutorials, reference material, and more, see Anthos components.

Access attached clusters

After you register an attached cluster, it appears in the GKE and Anthos clusters pages in the Google Cloud console. However, to see more details such as nodes and workloads, you need to log in and authenticate to the cluster. To log in to your attached clusters from the Google Cloud console, follow the instructions in Logging in to clusters from the Google Cloud console. Depending on the authentication method you choose, note that you or a platform admin may need to do some additional setup before you or other users are able to log in to the cluster.

To access attached clusters from the command line using a Google Cloud identity, see Connecting to registered clusters with the Connect gateway.

To authenticate to attached clusters using your existing third-party identity provider (EKS on AWS clusters only, preview feature), see Setting up Anthos Identity Service for a fleet and Accessing clusters with Anthos Identity Service.

What's next?