ExternalIP returns external IP for a node.

IsMaster returns true if the node's labels contains "node-role.kubernetes.io/master".

IsWorker returns true if the node's labels contains "node-role.kubernetes.io/node".

MustNewSSHClient returns *SSHClient.

NewScpClient returns scp client with given host and ssh client.

Retry retries f until f return nil error.

NodeRoleMasterLabel defines the master node's label.

NodeRoleWorkerLabel defines the worker node's label.

SSHClient holds config for ssh.