Setting up Django with Nginx, Gunicorn, virtualenv, supervisor and PostgreSQL
Django is an efficient, versatile and dynamically evolving web application development framework. When Django initially gained popularity, the recommended setup for running Django applications was based around Apache with mod_wsgi. The art of running Django advanced and these days the recommended configuration is more efficient and resilient, but also more complex and includes such tools as: Nginx, Gunicorn, virtualenv, supervisord and PostgreSQL.
In this text I will explain how to combine all of these components into a Django server running on Linux.
Prerequisites
I assume you have a server available on which you have root privileges. I am using a server running Debian 7, so everything here should also work on an Ubuntu server or other Debian-based distribution. If you’re using an RPM-based distro (such as CentOS), you will need to replace the aptitude commands by their yum counterparts and if you’re using FreeBSD you can install the components from ports.
If you don’t have a server to play with, I would recommend the inexpensive VPS servers offered by Digital Ocean. If you click through this link when signing up, you’ll pay a bit of my server bill :)
I’m also assuming you configured your DNS to point a domain at the server’s IP. In this text, I pretend your domain is example.com
Update your system
Let’s get started by making sure our system is up to date.
$ sudo aptitude update
$ sudo aptitude upgrade
PostgreSQL
To install PostgreSQL on a Debian-based system run this command:
$ sudo su - postgres
postgres@django:~$ createuser --interactive -P
Enter name of role to add: hello_django
Enter password for new role:
Enter it again:
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n
postgres@django:~$
postgres@django:~$ createdb --owner hello_django hello
postgres@django:~$ logout
$
Application user
Even though Django has a pretty good security track record, web applications can become compromised. If the application has limited access to resources on your server, potential damage can also be limited. Your web applications should run as system users with limited privileges.
Create a user for your app, named hello and assigned to a system group called webapps.
Install virtualenv and create an environment for you app
Virtualenv is a tool which allows you to create separate Python environments on your system. This allows you to run applications with different sets of requirements concurrently (e.g. one based on Django 1.5, another based on 1.6). virtualenv is easy to install on Debian:
$ sudo aptitude install python-virtualenv
Create and activate an environment for your application
I like to keep all my web apps in the /webapps/ directory. If you prefer /var/www/, /srv/ or something else, use that instead. Create a directory to store your application in /webapps/hello_django/ and change the owner of that directory to your application user hello
You can test it by running the development server:
(hello_django)hello@django:~$ cd hello
(hello_django)hello@django:~$ python manage.py runserver example.com:8000
Validating models...
0 errors found
June 09, 2013 - 06:12:00
Django version 1.5.1, using settings 'hello.settings'
Development server is running at http://example.com:8000/
Quit the server with CONTROL-C.
Allowing other users write access to the application directory
Your application will run as the user hello, who owns the entire application directory. If you want regular user to be able to change application files, you can set the group owner of the directory to users and give the group write permissions.
You can check what groups you’re a member of by issuing the groups command or id.
$ id
uid=1000(michal) gid=1000(michal) groups=1000(michal),27(sudo),100(users)
If you’re not a member of users, you can add yourself to the group with this command:
$ sudo usermod -a -G users `whoami`
Group memberships are assigned during login, so you may need to log out and back in again for the system to recognize your new group.
Configure PostgreSQL to work with Django
In order to use Django with PostgreSQL you will need to install the psycopg2 database adapter in your virtual environment. This step requires the compilation of a native extension (written in C). The compilation will fail if it cannot find header files and static libraries required for linking C programs with libpq (library for communication with Postgres) and building Python modules (python-dev package). We have to install these two packages first, then we can install psycopg2 using PIP.
You should now be able to access the Gunicorn server from http://example.com:8001 . I intentionally changed port 8000 to 8001 to force your browser to establish a new connection.
Gunicorn is installed and ready to serve your app. Let’s set some configuration options to make it more useful. I like to set a number of parameters, so let’s put them all into a small BASH script, which I save as bin/gunicorn_start
#!/bin/bash
NAME="hello_app" # Name of the application
DJANGODIR=/webapps/hello_django/hello # Django project directory
SOCKFILE=/webapps/hello_django/run/gunicorn.sock # we will communicte using this unix socket
USER=hello # the user to run as
GROUP=webapps # the group to run as
NUM_WORKERS=3 # how many worker processes should Gunicorn spawn
DJANGO_SETTINGS_MODULE=hello.settings # which settings file should Django use
DJANGO_WSGI_MODULE=hello.wsgi # WSGI module name
echo "Starting $NAME as `whoami`"
# Activate the virtual environment
cd $DJANGODIR
source ../bin/activate
export DJANGO_SETTINGS_MODULE=$DJANGO_SETTINGS_MODULE
export PYTHONPATH=$DJANGODIR:$PYTHONPATH
# Create the run directory if it doesn't exist
RUNDIR=$(dirname $SOCKFILE)
test -d $RUNDIR || mkdir -p $RUNDIR
# Start your Django Unicorn
# Programs meant to be run under supervisor should not daemonize themselves (do not use --daemon)
exec ../bin/gunicorn ${DJANGO_WSGI_MODULE}:application \
--name $NAME \
--workers $NUM_WORKERS \
--user=$USER --group=$GROUP \
--bind=unix:$SOCKFILE \
--log-level=debug \
--log-file=-
# view rawgunicorn_start.bash hosted with ❤ by GitHub
Set the executable bit on the gunicorn_start script:
$ sudo chmod u+x bin/gunicorn_start
You can test your gunicorn_start script by running it as the user hello.
Note the parameters set in gunicorn_start. You’ll need to set the paths and filenames to match your setup.
As a rule-of-thumb set the --workers (NUM_WORKERS) according to the following formula: 2 * CPUs + 1. The idea being, that at any given time half of your workers will be busy doing I/O. For a single CPU machine it would give you 3.
The --name (NAME) argument specifies how your application will identify itself in programs such as top or ps. It defaults to gunicorn, which might make it harder to distinguish from other apps if you have multiple Gunicorn-powered applications running on the same server.
In order for the --name argument to have an effect you need to install a Python module called setproctitle. To build this native extension pip needs to have access to C header files for Python. You can add them to your system with the python-dev package and then install setproctitle.
Now when you list processes, you should see which gunicorn belongs to which application.
$ ps aux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
(...)
hello 11588 0.7 0.2 58400 11568 ? S 14:52 0:00 gunicorn: master [hello_app]
hello 11602 0.5 0.3 66584 16040 ? S 14:52 0:00 gunicorn: worker [hello_app]
hello 11603 0.5 0.3 66592 16044 ? S 14:52 0:00 gunicorn: worker [hello_app]
hello 11604 0.5 0.3 66604 16052 ? S 14:52 0:00 gunicorn: worker [hello_app]
Starting and monitoring with Supervisor
Your gunicorn_start script should now be ready and working. We need to make sure that it starts automatically with the system and that it can automatically restart if for some reason it exits unexpectedly. These tasks can easily be handled by a service called supervisord. Installation is simple:
$ sudo aptitude install supervisor
When Supervisor is installed you can give it programs to start and watch by creating configuration files in the /etc/supervisor/conf.d directory. For our hello application we’ll create a file named /etc/supervisor/conf.d/hello.conf with this content:
[program:hello]
command = /webapps/hello_django/bin/gunicorn_start ; Command to start app
user = hello ; User to run as
stdout_logfile = /webapps/hello_django/logs/gunicorn_supervisor.log ; Where to write log messages
redirect_stderr = true ; Save stderr in the same log
environment=LANG=en_US.UTF-8,LC_ALL=en_US.UTF-8 ; Set UTF-8 as default encoding
view rawhello.conf hosted with ❤ by GitHub
You can set many other options, but this basic configuration should suffice.
Create the file to store your application’s log messages:
After you save the configuration file for your program you can ask supervisor to reread configuration files and update (which will start your the newly registered app).
$ sudo supervisorctl reread
hello: available
$ sudo supervisorctl update
hello: added process group
You can also check the status of your app or start, stop or restart it using supervisor.
Your application should now be automatically started after a system reboot and automatically restarted if it ever crashed for some reason.
Nginx
Time to set up Nginx as a server for out application and its static files. Install and start Nginx:
$ sudo aptitude install nginx
$ sudo service nginx start
You can navigate to your server (http://example.com) with your browser and Nginx should greet you with the words “Welcome to nginx!”.
Create an Nginx virtual server configuration for Django
Each Nginx virtual server should be described by a file in the /etc/nginx/sites-available directory. You select which sites you want to enable by making symbolic links to those in the /etc/nginx/sites-enabled directory.
Create a new nginx server configuration file for your Django application running on example.com in /etc/nginx/sites-available/hello. The file should contain something along the following lines. A more detailed example is available from the folks who make Gunicorn.
upstream hello_app_server {
# fail_timeout=0 means we always retry an upstream even if it failed
# to return a good HTTP response (in case the Unicorn master nukes a
# single worker for timing out).
server unix:/webapps/hello_django/run/gunicorn.sock fail_timeout=0;
}
server {
listen 80;
server_name example.com;
client_max_body_size 4G;
access_log /webapps/hello_django/logs/nginx-access.log;
error_log /webapps/hello_django/logs/nginx-error.log;
location /static/ {
alias /webapps/hello_django/static/;
}
location /media/ {
alias /webapps/hello_django/media/;
}
location / {
# an HTTP header important enough to have its own Wikipedia entry:
# http://en.wikipedia.org/wiki/X-Forwarded-For
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# enable this if and only if you use HTTPS, this helps Rack
# set the proper protocol for doing redirects:
# proxy_set_header X-Forwarded-Proto https;
# pass the Host: header from the client right along so redirects
# can be set properly within the Rack application
proxy_set_header Host $http_host;
# we don't want nginx trying to do something clever with
# redirects, we set the Host: header above already.
proxy_redirect off;
# set "proxy_buffering off" *only* for Rainbows! when doing
# Comet/long-poll stuff. It's also safe to set if you're
# using only serving fast clients with Unicorn + nginx.
# Otherwise you _want_ nginx to buffer responses to slow
# clients, really.
# proxy_buffering off;
# Try to serve static files from nginx, no point in making an
# *application* server like Unicorn/Rainbows! serve static files.
if (!-f $request_filename) {
proxy_pass http://hello_app_server;
break;
}
}
# Error pages
error_page 500 502 503 504 /500.html;
location = /500.html {
root /webapps/hello_django/static/;
}
}
view rawhello.nginxconf hosted with ❤ by GitHub
Create a symbolic link in the sites-enabled folder:
If you navigate to your site, you should now see your Django welcome-page powered by Nginx and Gunicorn. Go ahead and develop to your heart’s content.
At this stage you may find that instead of the Django welcome-page, you encounter the default “Welcome to nginx!” page. This may be caused by the default configuration file, which is installed with Nginx and masks your new site’s configuration. If you don’t plan to use it, delete the symbolic link to this file from /etc/nginx/sites-enabled.
If you run into any problems with the above setup, please drop me a line.
Final directory structure
If you followed this tutorial, you should have created a directory structure resembling this:
/webapps/hello_django/
├── bin <= Directory created by virtualenv
│ ├── activate <= Environment activation script
│ ├── django-admin.py
│ ├── gunicorn
│ ├── gunicorn_django
│ ├── gunicorn_start <= Script to start application with Gunicorn
│ └── python
├── hello <= Django project directory, add this to PYTHONPATH
│ ├── manage.py
│ ├── project_application_1
│ ├── project_application_2
│ └── hello <= Project settings directory
│ ├── __init__.py
│ ├── settings.py <= hello.settings - settings module Gunicorn will use
│ ├── urls.py
│ └── wsgi.py <= hello.wsgi - WSGI module Gunicorn will use
├── include
│ └── python2.7 -> /usr/include/python2.7
├── lib
│ └── python2.7
├── lib64 -> /webapps/hello_django/lib
├── logs <= Application logs directory
│ ├── gunicorn_supervisor.log
│ ├── nginx-access.log
│ └── nginx-error.log
├── media <= User uploaded files folder
├── run
│ └── gunicorn.sock
└── static <= Collect and serve static files from here
Uninstalling the Django application
If time comes to remove the application, follow these steps.
Remove the virtual server from Nginx sites-enabled folder:
$ sudo rm /etc/nginx/sites-enabled/hello_django
Restart Nginx:
$ sudo service nginx restart
If you never plan to use this application again, you can remove its config file also from the sites-available directory
$ sudo rm /etc/nginx/sites-available/hello_django
Stop the application with Supervisor:
$ sudo supervisorctl stop hello
Remove the application from Supervisor’s control scripts directory:
$ sudo rm /etc/supervisor/conf.d/hello.conf
If you never plan to use this application again, you can now remove its entire directory from webapps:
$ sudo rm -r /webapps/hello_django
Running multiple applications
If you would like some help with setting up a Nginx server to run multiple Django applications, check out my next article.
原始链接:http://michal.karzynski.pl/blog/2013/06/09/django-nginx-gunicorn-virtualenv-supervisor/
Setting up Django with Nginx, Gunicorn, virtualenv, supervisor and PostgreSQL
Django is an efficient, versatile and dynamically evolving web application development framework. When Django initially gained popularity, the recommended setup for running Django applications was based around Apache with mod_wsgi. The art of running Django advanced and these days the recommended configuration is more efficient and resilient, but also more complex and includes such tools as: Nginx, Gunicorn, virtualenv, supervisord and PostgreSQL.
In this text I will explain how to combine all of these components into a Django server running on Linux.
Prerequisites
I assume you have a server available on which you have root privileges. I am using a server running Debian 7, so everything here should also work on an Ubuntu server or other Debian-based distribution. If you’re using an RPM-based distro (such as CentOS), you will need to replace the
aptitude
commands by theiryum
counterparts and if you’re using FreeBSD you can install the components from ports.If you don’t have a server to play with, I would recommend the inexpensive VPS servers offered by Digital Ocean. If you click through this link when signing up, you’ll pay a bit of my server bill :)
I’m also assuming you configured your DNS to point a domain at the server’s IP. In this text, I pretend your domain is
example.com
Update your system
Let’s get started by making sure our system is up to date.
PostgreSQL
To install PostgreSQL on a Debian-based system run this command:
Create a database user and a new database for the app. Grab a perfect password from GRC.
Application user
Even though Django has a pretty good security track record, web applications can become compromised. If the application has limited access to resources on your server, potential damage can also be limited. Your web applications should run as system users with limited privileges.
Create a user for your app, named
hello
and assigned to a system group calledwebapps
.Install virtualenv and create an environment for you app
Virtualenv is a tool which allows you to create separate Python environments on your system. This allows you to run applications with different sets of requirements concurrently (e.g. one based on Django 1.5, another based on 1.6). virtualenv is easy to install on Debian:
Create and activate an environment for your application
I like to keep all my web apps in the
/webapps/
directory. If you prefer/var/www/
,/srv
/ or something else, use that instead. Create a directory to store your application in/webapps/hello_django/
and change the owner of that directory to your application userhello
As the application user create a virtual Python environment in the application directory:
Your environment is now activated and you can proceed to install Django inside it.
Your environment with Django should be ready to use. Go ahead and create an empty Django project.
You can test it by running the development server:
You should now be able to access your development server from http://example.com:8000
Allowing other users write access to the application directory
Your application will run as the user
hello
, who owns the entire application directory. If you want regular user to be able to change application files, you can set the group owner of the directory tousers
and give the group write permissions.You can check what groups you’re a member of by issuing the
groups
command orid
.If you’re not a member of
users
, you can add yourself to the group with this command:In order to use Django with PostgreSQL you will need to install the
psycopg2
database adapter in your virtual environment. This step requires the compilation of a native extension (written in C). The compilation will fail if it cannot find header files and static libraries required for linking C programs withlibpq
(library for communication with Postgres) and building Python modules (python-dev
package). We have to install these two packages first, then we can install psycopg2 using PIP.Install dependencies:
Install
psycopg2
database adapter:You can now configure the databases section in your
settings.py
:And finally build the initial database for Django:
Gunicorn
In production we won’t be using Django’s single-threaded development server, but a dedicated application server called gunicorn.
Install gunicorn in your application’s virtual environment:
Now that you have gunicorn, you can test whether it can serve your Django application by running the following command:
You should now be able to access the Gunicorn server from http://example.com:8001 . I intentionally changed port 8000 to 8001 to force your browser to establish a new connection.
Gunicorn is installed and ready to serve your app. Let’s set some configuration options to make it more useful. I like to set a number of parameters, so let’s put them all into a small BASH script, which I save as
bin/gunicorn_start
Set the executable bit on the
gunicorn_star
t script:You can test your
gunicorn_start
script by running it as the userhello
.Note the parameters set in
gunicorn_start
. You’ll need to set the paths and filenames to match your setup.As a rule-of-thumb set the
--worker
s (NUM_WORKERS
) according to the following formula: 2 * CPUs + 1. The idea being, that at any given time half of your workers will be busy doing I/O. For a single CPU machine it would give you 3.The
--name
(NAME
) argument specifies how your application will identify itself in programs such astop
orps
. It defaults togunicorn
, which might make it harder to distinguish from other apps if you have multiple Gunicorn-powered applications running on the same server.In order for the
--name
argument to have an effect you need to install a Python module calledsetproctitle
. To build this native extensionpip
needs to have access to C header files for Python. You can add them to your system with thepython-dev
package and then installsetproctitle
.Now when you list processes, you should see which gunicorn belongs to which application.
Starting and monitoring with Supervisor
Your
gunicorn_start
script should now be ready and working. We need to make sure that it starts automatically with the system and that it can automatically restart if for some reason it exits unexpectedly. These tasks can easily be handled by a service called supervisord. Installation is simple:When Supervisor is installed you can give it programs to start and watch by creating configuration files in the
/etc/supervisor/conf.d
directory. For ourhello
application we’ll create a file named/etc/supervisor/conf.d/hello.con
f with this content:view rawhello.conf hosted with ❤ by GitHub
You can set many other options, but this basic configuration should suffice.
Create the file to store your application’s log messages:
After you save the configuration file for your program you can ask supervisor to reread configuration files and update (which will start your the newly registered app).
You can also check the status of your app or start, stop or restart it using supervisor.
Your application should now be automatically started after a system reboot and automatically restarted if it ever crashed for some reason.
Nginx
Time to set up Nginx as a server for out application and its static files. Install and start Nginx:
You can navigate to your server (http://example.com) with your browser and Nginx should greet you with the words “Welcome to nginx!”.
Create an Nginx virtual server configuration for Django
Each Nginx virtual server should be described by a file in the
/etc/nginx/sites-available
directory. You select which sites you want to enable by making symbolic links to those in the/etc/nginx/sites-enabled
directory.Create a new nginx server configuration file for your Django application running on example.com in
/etc/nginx/sites-available/hello
. The file should contain something along the following lines. A more detailed example is available from the folks who make Gunicorn.view rawhello.nginxconf hosted with ❤ by GitHub
Create a symbolic link in the sites-enabled folder:
Restart Nginx:
If you navigate to your site, you should now see your Django welcome-page powered by Nginx and Gunicorn. Go ahead and develop to your heart’s content.
If you run into any problems with the above setup, please drop me a line.
Final directory structure
If you followed this tutorial, you should have created a directory structure resembling this:
Uninstalling the Django application
If time comes to remove the application, follow these steps.
Remove the virtual server from Nginx
sites-enabled
folder:Restart Nginx:
If you never plan to use this application again, you can remove its config file also from the
sites-available
directoryStop the application with Supervisor:
Remove the application from Supervisor’s control scripts directory:
If you never plan to use this application again, you can now remove its entire directory from
webapps
:Running multiple applications
If you would like some help with setting up a Nginx server to run multiple Django applications, check out my next article.