Apache2, mod_wsgi and django setup

[Gary Roach]

Setup for Django development system

OS Debian Linux 8 (jessie) using systemd, not init.d
Python 3.4.2
Django 1.8.5
Apache2 2.4.10 Debian (mmm-worker)
mod_wsgi 4.3.0
Postgresql 9.4.5

Two virtual environments: archive (actual project) and mysite (django
tutorial). Setup done with python3 -m venv <project name>. There seems
to be some variation between this setup and the one using virtualenv.
Confusing.

pip3 install mod_wsgi in each environment
Run mod_wsgi-express with install-module and setup-server for each.

In /etc/apache2/envvars the following environmental variables are set.
export APACHE_RUN_USER=www-data
export APACHE_RUN_GROUP=www-data

In /etc/apache2/apache2.conf the following environmental variables are
used to set user and group.
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

But starting from within the project with mod_wsgi-express start-server
gives:

WARNING: When running as the 'root' user, it is required that the
options '--user' and '--group' be specified to mod_wsgi-express.

Starting with apachectl start or python manage.py runserver give no
errors. Both servers work.

Questions:
What user is apache running as if started with apachectl?
What user is apache running as if started with python manage.py runserver?
How do I assure that Apache is running as www-data?
Do I need to start Apache with mod_wsgi-express --user www-data --group
www-data or is python manage.py runserver good enough?

Answers to these questions would be very very helpful

Gary R

[Andrew Farrell]

Others on here should jump in with help with your other questions but I think you should find the answers to your first and third by running `ps aux | grep apache` and looking at the first column. You might also find it enlightening to run `ps auxf | grep apache -B 2`.

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[James Schneider]

On Thu, Nov 12, 2015 at 2:34 PM, Gary Roach <gary71...@verizon.net> wrote:

Setup for Django development system

OS Debian Linux 8 (jessie) using systemd, not init.d
Python 3.4.2
Django 1.8.5
Apache2 2.4.10 Debian (mmm-worker)
mod_wsgi 4.3.0
Postgresql 9.4.5

Two virtual environments: archive (actual project) and mysite (django tutorial). Setup done with python3 -m venv <project name>. There seems to be some variation between this setup and the one using virtualenv. Confusing.

Somewhat, yes, although both are effectively the same process. You end up with the same thing either way, though. The 'old' way of installing the virtualenv packages and then creating the virtualenv with external shell commands was integrated natively into Python 3 (ie your python3 -m venv command), hence the confusion.

 

pip3 install mod_wsgi in each environment
Run mod_wsgi-express with install-module and setup-server for each.

That's interesting, I've never heard of mod_wsgi-express. From a quick google though, it appears it should only be used for testing a mod_wsgi installation, not for production runs. Generally things work the other way around (Apache configured to use the mod_wsgi module as it is needed).

 

In /etc/apache2/envvars the following environmental variables are set.
export APACHE_RUN_USER=www-data
export APACHE_RUN_GROUP=www-data

In /etc/apache2/apache2.conf the following environmental variables are used to set user and group.
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

But starting from within the project with mod_wsgi-express start-server gives:

WARNING: When running as the 'root' user, it is required that the options '--user' and '--group' be specified to mod_wsgi-express.

Starting with apachectl start or python manage.py runserver give no errors. Both servers work.

Questions:
        What user is apache running as if started with apachectl?

This tends to be distribution specific. Most often it will be www, or www-data. The serivce user account is generally specified by the service daemon management system configuration scripts for Apache/httpd (Systemd in this case). 

 

        What user is apache running as if started with python manage.py runserver?

It isn't. The runserver command is running its own bare-bones web server that is built into Python/Django (WEBrick IIRC, or at least it was previously). Only to be used for development, not for production.

 

        How do I assure that Apache is running as www-data?

Running ps -ef | grep -i '\(apache|http\)' should give you the user that the processes (Apache and all of its children) are running as in the first column.

 

        Do I need to start Apache with mod_wsgi-express --user www-data --group www-data or is python manage.py runserver good enough?

You should not be using either of those methods for a production installation of your project. Configure Apache directly to reference mod_wsgi. 

https://docs.djangoproject.com/en/1.8/howto/deployment/wsgi/modwsgi/

 

Answers to these questions would be very very helpful

Gary R

Is there a specific reason that you installed a custom version of mod_wsgi? Most distributions provide a 2.7 and 3.X compatible version of mod_wsgi along with their Apache installations (or provide package installations for mod_wsgi for each respective Python version). High-end installations with node management and configuration control tend to use custom compiled versions since they can manage them effectively. The rest of us peasants are probably better off using the distribution packages until we figure out what we're doing (myself included).

Out of curiosity, I logged into one of my Debian 8 boxen and verified that this is the case:

$ apt-cache search mod-wsgi

libapache2-mod-wsgi - Python WSGI adapter module for Apache

libapache2-mod-wsgi-py3 - Python 3 WSGI adapter module for Apache

$ apt-cache showpkg libapache2-mod-wsgi-py3

Package: libapache2-mod-wsgi-py3

Versions: 

4.3.0-1 (/var/lib/apt/lists/mirrors.ocf.berkeley.edu_debian_dists_jessie_main_binary-amd64_Packages)

 Description Language: 

                 File: /var/lib/apt/lists/mirrors.ocf.berkeley.edu_debian_dists_jessie_main_binary-amd64_Packages

                  MD5: 9804c7965adca269cbc58c4a8eb236d8

 Description Language: en

                 File: /var/lib/apt/lists/mirrors.ocf.berkeley.edu_debian_dists_jessie_main_i18n_Translation-en

                  MD5: 9804c7965adca269cbc58c4a8eb236d8

Reverse Depends: 

  apache2.2-common,libapache2-mod-wsgi-py3 3.4-2

  dms-wsgi,libapache2-mod-wsgi-py3

  apache2.2-common,libapache2-mod-wsgi-py3 3.4-2

Dependencies: 

4.3.0-1 - libc6 (2 2.14) libpython3.4 (2 3.4.2~rc1) apache2-api-20120211 (0 (null)) python3 (2 3.4) python3 (3 3.5) libapache2-mod-wsgi (0 (null)) 

Provides: 

4.3.0-1 - httpd-wsgi 

Reverse Provides: 

Looks like Debian 8 supports your version of Python (3.4.2) for mod_wsgi out of the box, with no fussing around with Python versions, etc. It should be no trouble to have it use your existing virtualenv as well. That would be my recommendation to save yourself a ton of headache.

-James

[Gary Roach]

Andrew;
    I forgot all about the process tables. Thanks. Interesting though, systemctl and mod_wsgi both start a root instance and then fork off 3-4 www-data instances. I assume that this is normal. The python manage.py runserver on the other hand doesn't even show up in the process table. I suspect it's using the internal development server. Nice to know.

James;
    See below

On 11/12/2015 03:24 PM, James Schneider wrote:

On Thu, Nov 12, 2015 at 2:34 PM, Gary Roach <gary71...@verizon.net> wrote:

Setup for Django development system

OS Debian Linux 8 (jessie) using systemd, not init.d
Python 3.4.2
Django 1.8.5
Apache2 2.4.10 Debian (mmm-worker)
mod_wsgi 4.3.0
Postgresql 9.4.5

Two virtual environments: archive (actual project) and mysite (django tutorial). Setup done with python3 -m venv <project name>. There seems to be some variation between this setup and the one using virtualenv. Confusing.

Somewhat, yes, although both are effectively the same process. You end up with the same thing either way, though. The 'old' way of installing the virtualenv packages and then creating the virtualenv with external shell commands was integrated natively into Python 3 (ie your python3 -m venv command), hence the confusion.

Thanks for the clarification. Between switching between Python 2 and Python 3, the differences between Debian and systemd vs the other versions and  everyone taking a different approach to the same problem, us novices get really confused.

 

pip3 install mod_wsgi in each environment
Run mod_wsgi-express with install-module and setup-server for each.

That's interesting, I've never heard of mod_wsgi-express. From a quick google though, it appears it should only be used for testing a mod_wsgi installation, not for production runs. Generally things work the other way around (Apache configured to use the mod_wsgi module as it is needed).

Which is exactly where I am at present. I'll fight the production stuff later.

 

In /etc/apache2/envvars the following environmental variables are set.
export APACHE_RUN_USER=www-data
export APACHE_RUN_GROUP=www-data

In /etc/apache2/apache2.conf the following environmental variables are used to set user and group.
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

But starting from within the project with mod_wsgi-express start-server gives:

WARNING: When running as the 'root' user, it is required that the options '--user' and '--group' be specified to mod_wsgi-express.

Starting with apachectl start or python manage.py runserver give no errors. Both servers work.

Questions:
        What user is apache running as if started with apachectl?

This tends to be distribution specific. Most often it will be www, or www-data. The serivce user account is generally specified by the service daemon management system configuration scripts for Apache/httpd (Systemd in this case). 

 

        What user is apache running as if started with python manage.py runserver?

It isn't. The runserver command is running its own bare-bones web server that is built into Python/Django (WEBrick IIRC, or at least it was previously). Only to be used for development, not for production.

Which I discovered to my surprise. See above.

Well thats interesting. Guess I'm going to have to go back and back out some of the software. I really don't think I'm that dumb (getting senile maybe) but the plethora of information out there gets really confusing after a bit. I really thank both of you for your help. See you all with my next problem.

Gary R.

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