http://articles.slicehost.com/2009/3/13/ubuntu-intrepid-nginx-rails-and-thin
Having installed the thin web server for Ruby, we can now look at configuring an Nginx vhost to proxy to thin so we can serve our Ruby on Rails application.
The process is easy to follow and easy to repeat for hosting multiple domains.
Setup
First, you need to have followed the previous Nginx articles, having installed Nginx via aptitude or via source.
You will also need to have installed the thin web server — see the article linked above.
Plan
The plan is very simple:
We’ll create a basic rails application and use 3 thin instances running from port 3000 to 3002.
I won’t go into detail as the thin web server for Ruby article shows how to install and configure thin.
Once that is done, we’ll create a simple vhost to proxy requests to the thin instances.
You may also notice this article is very similar to the Nginx and mongrels article. There is a very good reason for that — they use exactly the same methods in creating the virtual host.
All the virtual host has to do is proxy requests to the 3rd party web server — in this case thin, in the sister article, mongrels.
Rails Application
To create a rail application, move into your public_html folder:
cd /home/demo/public_html
and create a new Ruby on Rails application:
rails railsapp
Done.
Thin
Ensure you are in the rails folder:
cd ~/public_html/railsapp
Then create a thin configuration file:
sudo thin config -C /etc/thin/railsapp.yml -c /home/demo/public_html/railsapp/ --servers 3 -e production
It’s always a good idea to check the created file:
cat /etc/thin/railsapp.yml
The contents are as such:
---
pid: tmp/pids/thin.pid
address: 0.0.0.0
timeout: 30
port: 3000
log: log/thin.log
max_conns: 1024
require: []
environment: production
max_persistent_conns: 512
servers: 3
daemonize: true
chdir: /home/demo/public_html/railsapp
Unlike working with mongrels, with thin we don’t need to manually create symlinks, etc. to make sure it’s started after a reboot.
Now all we need to do is start thin:
sudo /etc/init.d/thin start
Done.
Nginx Virtual Host
Let’s create the Nginx vhost:
sudo nano /etc/nginx/sites-available/domain.com
Note: If you installed Nginx from source, the path may vary to something like:
sudo nano /usr/local/nginx/sites-available/domain.com
The contents of the file are as such:
upstream domain1 {
server 127.0.0.1:3000;
server 127.0.0.1:3001;
server 127.0.0.1:3002;
}
server {
listen 80;
server_name www.domain.com;
rewrite ^/(.*) http://domain.com/$1 permanent;
}
server {
listen 80;
server_name domain.com;
access_log /home/demo/public_html/railsapp/log/access.log;
error_log /home/demo/public_html/railsapp/log/error.log;
root /home/demo/public_html/railsapp/public/;
index index.html;
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect false;
if (-f $request_filename/index.html) {
rewrite (.*) $1/index.html break;
}
if (-f $request_filename.html) {
rewrite (.*) $1.html break;
}
if (!-f $request_filename) {
proxy_pass http://domain1;
break;
}
}
}
Take it section by section and you will see that the basics are the same as for a ‘normal’ Nginx vhost.
We have the server_name, listen, log and index variables.
Where it differs is the addition of the Rails proxy settings.
In this example, we will use 3 thin instances running on ports 3000, 3001 and 3002 which I have defined in the ‘upstream’ setting. I’ve called it domain1 for ease of use.
The location settings say that if the requested file exists to serve the static version straight away.
And if the requested file doesn’t exist, pass the request to the thin server.
Enable
Remember that we need to ‘enable’ any available vhosts or it won’t be served (an easy thing to leave out).
Referring to the Nginx articles, all we need to do is create a simple symlink:
sudo ln -s /etc/nginx/sites-available/domain.com /etc/nginx/sites-enabled/domain.com
Or, if you installed Nginx from source:
sudo ln -s /usr/local/nginx/sites-available/domain.com /usr/local/nginx/sites-enabled/domain.com
Done.
Restart
Final step is to restart Nginx:
sudo /etc/init.d/nginx stop
...
sudo /etc/init.d/nginx start
Use the ‘stop’ and ‘start’ method as issuing a restart command does not always work with Nginx.
Navigate
All that’s left is to navigate to your domain:
http://www.domain.com
Where you will be greeted with the rails welcome page.
Summary
Setting up an Nginx virtual host to proxy to a thin server cluster is easy.
To serve multiple domains, simply repeat the process with the new domain details.
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