mlflow ui 启动报错No such file or directory: 'gunicorn': 'gunicorn'

1、mlflow ui 启动报错，信息如下：

[root@localhost mlflow]# mlflow ui
/usr/local/python3/lib/python3.6/importlib/_bootstrap.py:219: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  return f(*args, **kwds)
Traceback (most recent call last):
  File "/usr/bin/mlflow", line 11, in <module>
    sys.exit(cli())
  File "/usr/local/python3/lib/python3.6/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/python3/lib/python3.6/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/usr/local/python3/lib/python3.6/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/python3/lib/python3.6/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/python3/lib/python3.6/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/python3/lib/python3.6/site-packages/mlflow/cli.py", line 138, in ui
    _run_server(file_store, file_store, host, port, 1, None)
  File "/usr/local/python3/lib/python3.6/site-packages/mlflow/server/__init__.py", line 62, in _run_server
    env=env_map, stream_output=True)
  File "/usr/local/python3/lib/python3.6/site-packages/mlflow/utils/process.py", line 34, in exec_cmd
    stdin=subprocess.PIPE, **kwargs)
  File "/usr/local/python3/lib/python3.6/subprocess.py", line 709, in __init__
    restore_signals, start_new_session)
  File "/usr/local/python3/lib/python3.6/subprocess.py", line 1344, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'gunicorn': 'gunicorn'

2、原因：

　　mlflow启动时，会调用subprocess.PIPE创建子进程，子进程启动找不到gunicorn命令：

3、解决方法：

　　创建gunicorn软连接：

ln -s /usr/local/python3/bin/gunicorn /usr/bin/gunicorn

　　或者将

/usr/local/python3/bin添加到PATH，export PATH=${PATH}:/usr/local/python3/bin