- ``--master``: The master/rendezvous server, support http:// and etcd://, default with http://. e.g., ``--master=127.0.0.1:8080``. Default ``--log_dir=None``.
- ``--master``: The master/rendezvous server, support http:// and etcd://, default with http://. e.g., ``--master=127.0.0.1:8080``. Default ``--master=None``.
- ``--rank``: The rank of the node, can be auto assigned by master. Default ``--rank=-1``.
- ``--rank``: The rank of the node, can be auto assigned by master. Default ``--rank=-1``.