
Document MachineID as the preferred field from the discussion here: https://groups.google.com/d/msg/kubernetes-sig-node/_3mXXB1ohZs/EuYtCzHvBgAJ
Document MachineID as the preferred field from the discussion here: https://groups.google.com/d/msg/kubernetes-sig-node/_3mXXB1ohZs/EuYtCzHvBgAJ