This article is a simple tutorial for getting nginx and mongrel_clusters up and running for your rails applications. It’s based off the great intro article by
Ezra Zygmuntowicz
. I used his installation steps and configuration file. Please take a look at his articles for further details.

nginx
(pronounced: “engine x”) is an HTTP -server that is under active development by
Igor Sysoev
. It runs on any nix platform, including OSX (which we’ll be using in this tutorial), Solaris, Linux, and FreeBSD. For Rails applications, it’s meant to be used to serve your static and cached files inside your rails application. The rest is handled by a mongrel_cluster. Think of it as a replacement for either of the two current popular solutions, Apache 2.2 w/mod_proxy_balancer, or Lighttpd. Both sit in front of that mongrel_cluster and serve static content.

Setup:

Install mongrel:

sudo gem install mongrel

Install mongrel_cluster:

sudo gem install mongrel_cluster

Install nginx:

curl -O http://sysoev.ru/nginx/nginx-0.3.60.tar.gz
tar -xzvf nginx-0.3.60.tar.gz
cd nginx-0.3.60
./configure --sbin-path=/usr/local/sbin --with-http_ssl_module
make
sudo make install
sudo chmod +x /usr/local/sbin/nginx

Nginx will install to /usr/local/nginx and in there you will find the conf directory containing the nginx.conf file, the logs directory with the error and access logs, as well as the PID for the nginx process.

Once you’ve got everything installed, create a new Rails application wherever you’d like.

rails demo

Then, create a mongrel_cluster for your application. I’m going to use ports 8000 & 8001, but you can use whatever you’d like. I’ve also set the environment to production, but again, you can set that to whatever you’d like. This will create a config file located at demo/config/mongrel_cluster.yml. You can create as many mongrel instances as you would like.

mongrel_rails cluster::configure -p 8000 -e production -a 127.0.0.1

Start the mongrel cluster

mongrel_rails cluster::start

This can be stopped or restarted just as easily by typing:

mongrel_rails cluster::stop
mongrel_rails cluster::restart

So now your app should have it’s mongrel cluster running fine. You can test by loading up either http://localhost:8000/ or http://localhost:8001/.

Now go ahead and open up the nginx.conf file located at /usr/local/nginx/conf/nginx.conf in TextMate or your favorite editor. There is a default conf file there, but it wouldn’t hurt to back up the old one.

Paste in the following code or download a .conf file with the same info
here
:

worker_processes  2;
error_log  logs/error.log notice;
pid        logs/nginx.pid;
events {
worker_connections  1024;
}
http {
include       conf/mime.types;
default_type  application/octet-stream;
# no sendfile on OSX uncomment 
#this if your on linux or bsd
#sendfile        on;
tcp_nopush     on;
keepalive_timeout  65;
tcp_nodelay        on;
upstream mongrel {
server 127.0.0.1:8000;
server 127.0.0.1:8001;
}
gzip on;
gzip_min_length  1100;
gzip_buffers     4 8k;
gzip_types       text/plain;
server {
listen       80;
#server_name  localhost;
root /path_to/rails/public;
access_log  off;
rewrite_log on;
# / -> first search for local index.html then go to mongrel
location ~ ^/$ {
if (-f /index.html){
rewrite (.*) /index.html last;
}
proxy_pass  http://mongrel;
}
# rail caching: searching first for $action.html local pages
location / {
if (!-f $request_filename.html) {
proxy_pass  http://mongrel;
}
rewrite (.*) $1.html last;
}
# serve static files directly
location ~ .html {
root /path_to/rails/public;
}
location ~* ^.+\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js|mov)$ {
root /path_to/rails/public;
}
# resend everything else to mongrel
location / {
proxy_pass  http://mongrel;
proxy_redirect     off;
proxy_set_header   Host             $host;
proxy_set_header   X-Real-IP        $remote_addr;
proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
}
}
}

Set /path_to/rails/public to whatever the path to your rails app is.

Once you’ve gotten your nginx.conf file saved, fire up nginx and let it rip. You start nginx by calling that executable that was created when you built from source earlier. In the example above it would be:

sudo nginx

Sidenote:
make sure Apache is turned off, it’s most likely been turned on in Personal Web Sharing under System Preferences → Sharing. Load up http://localhost, and you should see a blank Rails app from there.

Nginx is managed by sending UNIX signals to that process, similar to apache. For more info on that, visit
Zhesto’s notes
.

Nginx has a lot of buzz right now about being a potential solution for being the lightweight front end for mongrel_clusters. Whether or not that happens remains to be seen, but hopefully now you can help make that decision.

All credit for this article goes to
Ezra Zygmuntowicz
and
Alexy Kovyrin
for posting enough info to get started, as well as
Bradley Taylor
for the mongrel_cluster plugin. Please check out those blogs for more information.