Adding an External GKE Kubernetes Cluster

Add GKE Cluster

You can add an existing Kubernetes cluster and then manage it using KKP. From the Clusters page, click External Clusters. Click the Add External Cluster button and Pick Google Kubernetes Engine provider.

Add External Cluster

Select preset with valid credentials or enter GKE Service Account to connect to the provider.

GKE credentials

You should see the list of all available clusters. Select the one and click the Import Cluster button. Clusters can be imported only once in a single project. The same cluster can be imported for the other projects.

Select GKE cluster

Cluster Details Page

After the cluster is added, the KKP controller retrieves the cluster kubeconfig to display all necessary information. A healthy cluster has Running state. Otherwise, the cluster can be in the Error state. Move the mouse cursor over the state indicator to get more details. You can also expand Events to get information from the controller.

GKE cluster

You can also click on Machine Deployments to get the details:

GKE Machine Deployment

Update Cluster

Upgrade Version

When an upgrade for the cluster is available, a little dropdown arrow will be shown beside the Master Version on the cluster’s page. To start the upgrade, just click on the link and choose the desired version:

Upgrade GKE

If the version upgrade is valid, the cluster state will change to Reconciling.

Scale the Machine Deployment

Navigate to the cluster overview, scroll down to machine deployments and click on the edit icon next to the machine deployment you want to edit. In the popup dialog, you can now increase or decrease the number of worker nodes that are managed by this machine deployment.

Update GKE Machine Deployment

Authenticating with GKE

The KKP platform allows getting kubeconfig file for the GKE cluster.

Get cluster kubeconfig

The end-user must be aware that the kubeconfig expires after some short period of time. To mitigate this disadvantage you can extend the kubeconfig for the provider information and use exported JSON with the service account for the authentication.

Add name: gcp for the users:

- name: gke_kubermatic-dev_europe-central2-a_test
      name: gcp

Provide authentication credentials to your application code by setting the environment variable GOOGLE_APPLICATION_CREDENTIALS. This variable applies only to your current shell session. If you want the variable to apply to future shell sessions, set the variable in your shell startup file, for example in the ~/.bashrc or ~/.profile file.


Replace KEY_PATH with the path of the JSON file that contains your service account key.

For example:

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"