Created by: LihangLiu

在fluid1.6上按照 quickstart来跑单机模拟多机 python -m paddle.distributed.launch_ps --worker_num 2 --server_num 2 train.py 出现如下错误：

Traceback (most recent call last):
  File "fleet-demo.py", line 46, in <module>
    fleet.init(role)
  File "/home/ol/anaconda2/envs/official/lib/python2.7/site-packages/paddle/fluid/incubate/fleet/base/fleet_base.py", line 202, in init
    self._role_maker.generate_role()
  File "/home/ol/anaconda2/envs/official/lib/python2.7/site-packages/paddle/fluid/incubate/fleet/base/role_maker.py", line 352, in generate_role
    training_role = os.environ["TRAINING_ROLE"]
  File "/home/ol/anaconda2/envs/official/lib/python2.7/UserDict.py", line 40, in __getitem__
    raise KeyError(key)
KeyError: 'TRAINING_ROLE'

系统信息：centos，fluid1.6 cpu版本。