Eu instalei o gunicorn dentro do meu virtualenv.

Nesse diretório:

manage.py
/onbytes/wsgi.py

Eu executo o seguinte:

gunicorn onbytes.wsgi:application

E eu recebo o seguinte erro:

Traceback (most recent call last):
  File "/home/ymorin007/.virtualenvs/onbytes.com/bin/gunicorn", line 9, in <module>
    load_entry_point('gunicorn==19.0.0', 'console_scripts', 'gunicorn')()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 74, in run
    WSGIApplication("%(prog)s [OPTIONS] [APP_MODULE]").run()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/base.py", line 166, in run
    super(Application, self).run()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/base.py", line 71, in run
    Arbiter(self).run()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 169, in run
    self.manage_workers()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 477, in manage_workers
    self.spawn_workers()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 537, in spawn_workers
    time.sleep(0.1 * random.random())
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 209, in handle_chld
    self.reap_workers()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 459, in reap_workers
    raise HaltServer(reason, self.WORKER_BOOT_ERROR)
gunicorn.errors.HaltServer: <HaltServer 'Worker failed to boot.' 3>

executando gunicorn onbytes.wsgi: application --preload irá obter esse erro:

Traceback (most recent call last):
  File "/home/ymorin007/.virtualenvs/onbytes.com/bin/gunicorn", line 9, in <module>
    load_entry_point('gunicorn==19.0.0', 'console_scripts', 'gunicorn')()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 74, in run
    WSGIApplication("%(prog)s [OPTIONS] [APP_MODULE]").run()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/base.py", line 166, in run
    super(Application, self).run()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/base.py", line 71, in run
    Arbiter(self).run()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 57, in __init__
    self.setup(app)
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 113, in setup
    self.app.wsgi()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/base.py", line 66, in wsgi
    self.callable = self.load()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 65, in load
    return self.load_wsgiapp()
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 52, in load_wsgiapp
    return util.import_app(self.app_uri)
  File "/home/ymorin007/.virtualenvs/onbytes.com/local/lib/python2.7/site-packages/gunicorn/util.py", line 356, in import_app
    __import__(module)
  File "/home/ymorin007/sites/onbytes.com/src/onbytes/wsgi.py", line 8, in <module>
    from django.core.wsgi import get_wsgi_application
ImportError: No module named django.core.wsgi