Using SSH to connect to a cluster node

This page describes how to SSH into an GKE on-prem cluster node.

Before you begin

To complete these steps, you need the location of your user and admin cluster kubeconfig files. By default, these files are stored in the directory where you created your admin and user clusters. For more information on kubeconfig, see Configuring cluster access for kubectl in the GKE documentation.

Getting the IP addresses of your cluster nodes

Get the IP addresses of your user cluster nodes:

kubectl --kubeconfig [USER_CLUSTER_KUBECONFIG] get nodes --output wide

where [USER_CLUSTER_KUBECONFIG] is the path of your user cluster's kubeconfig file.

Get the IP addresses of your admin cluster nodes:

kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] get nodes --output wide

where [ADMIN_CLUSTER_KUBECONFIG] is the path of your admin cluster's kubeconfig file.

For either command, note the INTERNAL-IP field. These are the node IP addresses.

Using SSH to connect to a user cluster node

Get the SSH key for a user cluster:

kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] get secrets -n [USER_CLUSTER_NAME] ssh-keys \
-o jsonpath='{.data.ssh\.key}' | base64 -d > \
~/.ssh/[USER_CLUSTER_NAME].key && chmod 600 ~/.ssh/[USER_CLUSTER_NAME].key

where:

  • [ADMIN_CLUSTER_KUBECONFIG] is the path of your admin cluster's kubeconfig file.

  • [USER_CLUSTER_NAME] is the name of your user cluster.

The preceding command performs the following steps:

  • From the admin cluster, get the ssh.key field of a Secret named ssh-keys in the [USER_CLUSTER_NAME] namespace.

  • Base64 decode the key.

  • Store the decoded key in the file ~/.ssh/[USER_CLUSTER_NAME].key.

  • Set appropriate access permissions for the key file.

Use the key to SSH into a user cluster node:

ssh -i ~/.ssh/[USER_CLUSTER_NAME].key ubuntu@[NODE_IP]

where [NODE_IP] is the internal IP address of a node in your user cluster, which you gathered previously.

Using SSH to connect to an admin cluster node

Get the SSH key for the admin cluster:

kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] get secrets -n kube-system sshkeys \
-o jsonpath='{.data.vsphere_tmp}' | base64 -d > \
~/.ssh/admin-cluster.key && chmod 600 ~/.ssh/admin-cluster.key

where [ADMIN_CLUSTER_KUBECONFIG] is the path of the admin cluster's kubeconfig file.

The preceding command performs the following steps:

  • From the admin cluster, get the vsphere_tmp field of a Secret named sshkeys in the kube-system namespace.

  • Base64 decode the vsphere_tmp field, which is the key.

  • Store the decoded key in the file ~/.ssh/admin-cluster.key.

  • Set appropriate access permissions for the key file.

Use the key to SSH into an admin cluster node:

ssh -i ~/.ssh/admin-cluster.key ubuntu@[NODE_IP]

where [NODE_IP] is the internal IP address of a node in the admin cluster, which you gathered previously.