My django application that accustomed to have spend instructions by utilizing python subprocess.Popen doesn't work any longer since i have upgrade to ubuntu to 11.10

To simplify the issue, I place the faulty code in to the wsgi script :

import os
import sys

from subprocess import Popen,PIPE
print comm,p.returncode

os.environ['DJANGO_SETTINGS_MODULE'] = 'settings'
import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()

Basically run this code directly by python, it really works :

$ python -V
Python 2.7.2+
$ python 
('uid=1002(www) gid=1002(www) groups=1002(www)\n', '') 0

Basically run this code by apache (I simply place the relevant URL right into a browser), within the apache log, I acquired :

[Tue Nov 29 11:34:38 2011] [error] ('', '') -6

What's this error '-6' ???

However , with my development server (Ubuntu 10.04, almost exactly the same apache/wsgi version, same apache configuration file, same atmosphere variables, however with python 2.6.5) it really works well :

[Tue Nov 29 11:29:10 2011] [error] ('uid=1000(www) gid=1000(www) groups=1000(www)\\n', '') 0

Are you aware why Popen isn't sort out apache any longer with python 2.7 ?

Because latest Python 2.7 includes a bug inside it which in turn causes fork run in sub interpreters to fail.

Supposing only hosting the main one WSGI application, pressure utilisation of the primary interpreter as opposed to a sub interpreter with the addition of for your Apache configuration:

WSGIApplicationGroup %{GLOBAL}