Set Up Ubuntu To Serve A Django Website Step By Step

Overview

This is a guide to have a website in an Ubuntu server using nginx and systemd.

Ubuntu uses systemd to manage system and service daemons and processes, we will create configuration files to:

• create temporary files
• manage gunicorn system service
• manage gunicorn system socket

And lastly configuring nginx to handle requests.

We assume the following configuration to set up the server, this is a basic configuration example to follow the tutorial and be easier to customize with your own data:

• website domain: example.com
• Django source code located in /home/chengue/sites/example
• environment variable pointing to production settings: DJANGO_SETTINGS_MODULE=example.settings.production
• Python virtual environment for the example project at: /home/chengue/.virtualenvs/example
• Ubuntu User: chengue

At the end of the tutorial we will have:

• nginx handling requests to example.com
• traffic gets redirected from non-www to www

Configuring Systemd services

Socket

To handle incoming Gunicorn requests we create a unix socket controlled by systemd. As the configuration filename should end in .socket we create the following file: /etc/systemd/system/gunicorn.socket.

[Unit]
Description=gunicorn socket

[Socket]
ListenStream=/run/gunicorn/socket

[Install]
WantedBy=sockets.target

*systemd* will listen on this socket and start **Gunicorn** automatically in response to traffic.

This sockets will be used by Gunicorn service using the parameter --bind unix:/run/gunicorn/socket in the service file.

Service

Then the service that use the above socket, In /etc/systemd/system/gunicorn.service:

[Unit]
Description=gunicorn daemon
Requires=gunicorn.socket
After=network.target

[Service]
PIDFile=/run/gunicorn/pid
User=chengue
Group=www-data
RuntimeDirectory=gunicorn
WorkingDirectory=/home/chengue/sites/example/example
ExecStart=/home/chengue/.virtualenvs/example/bin/gunicorn \
          --access-logfile /home/chengue/sites/logs/example.access.log \
          --error-logfile /home/chengue/sites/logs/example.error.log \
          --pid /run/gunicorn/pid   \
          --env DJANGO_SETTINGS_MODULE=example.settings.production \
          --bind unix:/run/gunicorn/socket example.wsgi
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s TERM $MAINPID
PrivateTmp=true

[Install]
WantedBy=multi-user.target

Temporal file

Temporal files handled by systemd are located in /etc/tmpfiles.d/, we create /etc/tmpfiles.d/gunicorn.conf with the following content:

d /run/gunicorn 0755 chengue www-data -

Web proxy

Lastly, configure the web proxy to send traffic to the Gunicorn socket. Create a virtual site in /etc/nginx/sites-available/example.com:

server {
	# redirect www to non-www
    server_name www.example.com;
    return 301 $scheme://example.com$request_uri;
}

server {
	server_name example.com;

	#location /static {
	#    alias /home/chengue/sites/example/static;
	#}

	#location /media {
	#    alias /home/chengue/sites/example/media;
	#}

	location / {
		proxy_set_header Host $host;
		proxy_pass http://unix:/run/gunicorn/socket;
	}
}

Now that we have our example.com configuration as an available website in nginx, we should enable it creating a symbolic link in /etc/nginx/sites-enabled/example.com pointing to the above file:

sudo ln -s /etc/nginx/sites-available/example.com
/etc/nginx/sites-enabled/example.com

Commands

Enabling services

Enable services to autostart at boot:

systemctl enable gunicorn.socket systemctl enable nginx.service

Activate services

Manually activating services:

systemctl start gunicorn.socket systemctl start nginx

Testing

To test if Gunicorn works curl –unix-socket /run/gunicorn/socket http should retrieve an HTML from the server.

Status

$ systemctl status gunicorn.socket
● gunicorn.socket - gunicorn socket
   Loaded: loaded (/etc/systemd/system/gunicorn.socket; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2017-07-03 18:52:15 EDT; 2h 58min ago
   Listen: /run/gunicorn/socket (Stream)

Jul 03 18:52:15  systemd[1]: Closed gunicorn socket.
Jul 03 18:52:15  systemd[1]: Stopping gunicorn socket.
Jul 03 18:52:15  systemd[1]: Listening on gunicorn socket.
$ systemctl status gunicorn.service
   Loaded: loaded (/etc/systemd/system/gunicorn.service; disabled; vendor preset: enabled)
   Active: active (running) since Mon 2017-07-03 18:52:15 EDT; 2h 59min ago
 Main PID: 14216 (gunicorn)
    Tasks: 2 (limit: 4915)
   Memory: 41.8M
      CPU: 5.544s
   CGroup: /system.slice/gunicorn.service
           ├─14216 /home/chengue/.virtualenvs/example/bin/python3.6 /home/chengue/.virtualenvs/example/bin/gunicorn --access
           └─14252 /home/chengue/.virtualenvs/pullgravity/bin/python3.6 /home/chengue/.virtualenvs/example/bin/gunicorn --access

Jul 03 18:52:15  systemd[1]: Started gunicorn daemon.
$ systemctl status nginx.service
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
  Drop-In: /etc/systemd/system/nginx.service.d
           └─override.conf
   Active: active (running) since Mon 2017-07-03 18:52:21 EDT; 3h 1min ago
     Docs: man:nginx(8)
 Main PID: 14353 (nginx)
    Tasks: 2 (limit: 4915)
   Memory: 2.8M
      CPU: 205ms
   CGroup: /system.slice/nginx.service
           ├─14353 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
           └─14357 nginx: worker process

Jul 03 18:52:21  systemd[1]: Starting A high performance web server and a reverse proxy server...
Jul 03 18:52:21  systemd[1]: Started A high performance web server and a reverse proxy server.

Debugging

An useful command to see systemd logs filtered by service is journalctl, it query the systemd journal and with the -u parameter show messages for the specified systemd unit.

Using our services:

journalctl -u nginx.service journalctl -u gunicorn.service journalctl -u gunicorn.socket

Repo

The files created in this tutorial are available in this Github repository: https://github.com/marcanuy/django-deploy-guide.

References

• Official page https://www.freedesktop.org/wiki/Software/systemd/
• Gunicorn systemd section http://docs.gunicorn.org/en/stable/deploy.html#systemd
• Linux manual pages:
  • man systemd.socket
  • man systemd.service
  • man tmpfiles.d
• Unix socket https://en.wikipedia.org/wiki/Unix_domain_socket
• nginx proxy http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_pass