airflow startup failed due to gunicorn

Question

Traceback (most recent call last):
  File "./python_runtime/bin/airflow", line 15, in <module>
    args.func(args)
  File "/home/admin/airflow/python_runtime/lib/python2.7/site-packages/airflow/bin/cli.py", line 423, in webserver
    'gunicorn', run_args
  File "/home/admin/airflow/python_runtime/lib/python2.7/os.py", line 346, in execvp
    _execvpe(file, args)
  File "/home/admin/airflow/python_runtime/lib/python2.7/os.py", line 385, in _execvpe
    func(fullname, *argrest)
OSError: [Errno 2] No such file or directory

I find out that this error was cause by no gunicorn avaiable,so I print all paths in os.py:

/home/admin/airflow/python_runtime/bin/gunicorn
/home/admin/python2.7.2/bin/gunicorn
/home/admin/tools/local/bin/gunicorn
/home/admin/tools/bin/gunicorn
/home/admin/tools/opsdb/gunicorn
/home/admin/odps_tools/dship/gunicorn
/home/admin/php/bin/gunicorn
/home/admin/cmake/bin/gunicorn
/home/admin/jdk1.6.0_24/bin/gunicorn
/home/admin/tools/bin/gunicorn
/usr/kerberos/bin/gunicorn
/usr/local/sbin/gunicorn
/usr/sbin/gunicorn
/sbin/gunicorn
/usr/local/bin/gunicorn
/bin/gunicorn
/usr/bin/gunicorn
/usr/X11R6/bin/gunicorn

while gunicorn exist in this path

/home/admin/airflow/python_runtime/bin/gunicorn

something wrong with my env?

Answer 1

Airflow seems to expect gunicorn in PATH. For my ubuntu instance this fixed it:

$ export PATH=$PATH:~/.local/bin $ airflow webserver

Answer 2

On MacOS, it wasn't enough with the proposed solution. If I used relative path (with either ~ or $HOME ) it didn't work, but using absolute path solved the issue: PATH="${PATH}:/path/to/.venv/bin"
As you can see, I'm using a hidden folder that I created with Python venv, maybe this is connected.

To test it, is not enough to run gunicorn alone, this worked to me with the relative path as well, but which gunicorn returned nothing, and this indicates that airflow webserver will fail to start.