Using SSH to connect to a cluster node

This page describes how to SSH into a GKE On-Prem cluster node.

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.

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 yaml \
| grep ssh.key: | awk '{ print $NF }' | 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 IP address of a node in the user cluster.

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 yaml \
| grep vsphere_tmp: | awk '{ print $NF }' | 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 IP address of a node in your admin cluster.