'ssh to master node of cluster_name
user keyword specifies an alternate user to login as'

def ssh_to_master(self, cluster_name, user='root', command=None, forward_x11=False, forward_agent=False, pseudo_tty=False):

    cluster = self.get_cluster(cluster_name, load_receipt=False, require_keys=True)
    return cluster.ssh_to_master(user=user, command=command, forward_x11=forward_x11, forward_agent=forward_agent, pseudo_tty=pseudo_tty)
