Apache2 AssertionError threading

The work around is from here.

Ubuntu 14.04 comes with mod_wsgi 3.4. According to https://code.djangoproject.com/ticket/22948#comment:2 we need to use mod_wsgi version 4.2+ for Python 3.4.
The best way to install mod_wsgi to the latest version is to get it with pip (can be in virtualenv) and then install its module to apache system-wide. In my case I use virtualenv set in /venv_path.
1) Remove problematic package and install dependency

sudo apt-get remove libapache2-mod-wsgi-py3
sudo apt-get install apache2-dev

2) Install mod_wsgi in virtualenv with pip

. /venv_path/bin/activate
pip install mod_wsgi

3) Install into Apache (system-wide)

sudo /venv_path/bin/mod_wsgi-express install-module
sudo vi /etc/apache2/mods-available/wsgi_express.load /etc/apache2/mods-available/wsgi_express.conf

Content of /etc/apache2/mods-available/wsgi_express.load

LoadModule wsgi_module /usr/lib/apache2/modules/mod_wsgi-py34.cpython-34m.so

Content of /etc/apache2/mods-available/wsgi_express.conf

WSGIPythonHome /venv_path

4) Enable the module and restart Apache.

sudo a2enmod wsgi_express
sudo service apache2 restart

5) Check that there are no errors in /var/log/apache2/error.log

The mod_wsgi-py34.cpython-34m.so is found from the venv/lib/python3.4/site-packages/mod_wsgi/server.