title: Unable to start Airflow Server - OSError: [Errno 2] No such file or directory
body: <p>I setup Airflow locally using the <a href="https://airflow.apache.org/docs/stable/installation.html" rel="nofollow noreferrer">Installation</a> and <a href="https://airflow.apache.org/docs/stable/start.html" rel="nofollow noreferrer">Quickstart</a> pages.</p>
  
  <p>I was able to originally get it up and running, and even follow the <a href="https://airflow.apache.org/docs/stable/tutorial.html" rel="nofollow noreferrer">Tutorial</a>.</p>
  
  <p>Then when trying my own example which required the following</p>
  
  <pre><code>pip install 'apache-airflow[gcp,google_auth]'
  </code></pre>
  
  <p>When I try to run webserver with <code>airflow webserver -p 8080</code> I get the following error:</p>
  
  <pre><code>Running the Gunicorn Server with:
  Workers: 4 sync
  Host: 0.0.0.0:8080
  Timeout: 120
  Logfiles: - -
  =================================================================
  Traceback (most recent call last):
    File "/usr/local/bin/airflow", line 37, in &lt;module&gt;
      args.func(args)
    File "/Library/Python/2.7/site-packages/airflow/utils/cli.py", line 75, in wrapper
      return f(*args, **kwargs)
    File "/Library/Python/2.7/site-packages/airflow/bin/cli.py", line 996, in webserver
      gunicorn_master_proc = subprocess.Popen(run_args, close_fds=True)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 394, in __init__
      errread, errwrite)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1047, in _execute_child
      raise child_exception
  OSError: [Errno 2] No such file or directory
  </code></pre>