I have my own dedicated server running Ensim on which I run quite a few sites. Most of these are either static HTML or PHP sites, but I also host a couple of Rails apps on the same box using Lighttpd. That has turned out not to be the most reliable setup. After a year of killing hung dispatchers I decided to give mongrel_cluster and Pound a try. This is how I did it.

Note that these instructions are specific to Redhat ES4 with Ensim, though most of this stuff should work on other flavors of *nix with some slight modifications.

Prerequisites

The only prerequisite for Pound that I am aware of is pcre. You probably already have it installed, but if you don’t, install in via up2date, yum, or whatever.

Installing Pound

Download, configure and install Pound. There are stable and experimental versions to choose from. I’m using the latest experimental release:

Test Configuration

I don’t like the default location for Pound’s configuration file, so I’ve created mine file here: /etc/pound/pound.cfg

In order to make sure everything is working as expected, we’re going to start with a test configuration. Something simple. Put this in your /etc/pound/pound.cfg file for now:

LogLevel 0
Alive 30

ListenHTTP
  Address 0.0.0.0
  Port 81

  Service
    BackEnd
      Address YOUR SERVER'S EXTERNAL IP
      Port 80
    End
  End

End

This configuration will proxy all inbound requests to port 81 over to Apache running on port 80. Now try to start up pound:

If it started properly, you’ll get no output. You should get an error if it couldn’t start up. Use

to see if it’s running. If so, try to browse to one of the sites on your server using port 81. For example: http://www.infused.org:81. If it works we’re in business, so we’ll create a pound start-up script and configure it to start up on boot.

Setup Pound daemon

Create a /etc/init.d/pound file with the following contents:

#!/bin/sh
. /etc/rc.d/init.d/functions

# To add to services:
# chkconfig --add pound

# Enable automatic start on boot
# chkconfig pound on

### BEGIN INIT INFO
# Provides:       pound
# Required-Start: $network $syslog
# Required-Stop:
# Default-Start:  3 5
# Default-Stop:
# Description:    Starts pound reverse proxy
### END INIT INFO

if [ -z "$POUND_CONF_PATH" ]; then
        POUND_CONF_PATH="/etc/pound/pound.conf"
fi

prog="pound"
pound="/usr/local/sbin/pound"
RETVAL=0

start() {
        echo -n $"Starting $prog: "
        daemon $pound -f $POUND_CONF_PATH
        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && touch /var/lock/subsys/$prog
        return $RETVAL
}

stop() {
        echo -n $"Stopping $prog: "
        killproc $pound
        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$prog
        return $RETVAL
}

reload() {
        echo -n $"Reloading $prog: "
        killproc $pound -HUP
        RETVAL=$?
        echo
        return $RETVAL
}

case "$1" in
        start)
                start
                ;;
        stop)
                stop
                ;;
        restart)
                stop
                start
                ;;
        condrestart)
                if [ -f /var/lock/subsys/$prog ]; then
                        stop
                        start
                fi
                ;;
        reload)
                reload
                ;;
        status)
                status $pound
                RETVAL=$?
                ;;
        *)
                echo $"Usage: $0 {start|stop|restart|condrestart|reload|status}"
                RETVAL=1
esac

exit $RETVAL

Now you can configure Pound as a service and set it to start on boot:

Use the ps command again to find and then kill the pound instance you started earlier. You will probably see to instances running. Kill the first one, and the other will die with it. Once the test instance is dead, you can start, stop, and restart Pound like any other service. To start it up as a service:

The Real Deal

Test it by browsing to a site on port 81 again. If everything looks good, it’s time to do this thing for real. Edit /etc/pound/pound.cfg and swap the ports between the proxy and the backend server. The file should now look like this:

LogLevel 0
Alive 30

ListenHTTP
  Address 0.0.0.0
  Port 80

  Service
    BackEnd
      Address 67.15.198.2
      Port 81
    End
  End

End

Log into your Ensim control panel as the Appliance Administrator and click on the Web Server link. Change port 80 to 81 and click Update Configuration.

With the appliance updated, we now need to restart Apache and Pound to pick up their new configurations:

All your sites should now be accessible on port 80. Try them out. If you don’t see any problems, there is one important step left to do.

Fix Apache Logging

Right now, all the Apache logs will show you server’s IP address as the remote address. To fix this, you need to swap out %h for \”%{X-Forwarded-for}i\” in any LogFormat line in /etc/httpd/conf/httpd20_app.conf

You may have LogFormat lines in other files too, such as /etc/httpd/conf/httpd.conf. Change those too.

My LogFormat directive now looks like this (on one line):

Restart Apache again and you’re done.

Subversion

If you are running Subversion under Apache, you’ll also need to tell Pound to allow the proper HTTP verbs. Add the following line to /etc/pound/pound.cfg, right under ListenHTTP:

By the way, this also tells Pound to allow the PUT and DELETE verbs, which you’ll need if you’re using the map.resources stuff in Rails.

Additional Resources

• Official Pound site
• Deploying Rails with Pound in Front of Mongrel, Lighttpd, and Apache

Coming Up

The stage is now set for Part 2, where I set up Pound to proxy to several Rails apps which are running under mongrel_cluster. Stay tuned.

A reminder to myself and others:

You should understand, that in truth, no genuine satisfaction in life can ever be attained by you or anyone else, who simply refuses to take risks. For the life of anyone who chooses to live with extreme caution will never amount to anything more than a succession of dull, soporific days, continuing on, without interruption.”

I wrote this quote down some time ago, but failed to write down where I got it. If you know where this quote originated, please let know.

The DBF library project page is up:
http://rubyforge.org/projects/dbf/

There’s no documentation yet, but you should be able to figure out how to use it by looking at the unit tests.

You can download it from the project page as a gem or tar.gz or install it via rubygems:

gem install dbf

I’ve been working on a very large Rails projects at work and found myself spending a lot of time writing the same unit tests over and over again. The application has a very complex database schema and has 159 ActiveRecord models so far. With this many models, there are obviously a ton of associations. I decided that I needed a way to automatically test every association that is defined in a model.

The TestInjector plugin is the result. I still have a lot of functionality that I want to add, but it works very well and it’s ready for others to use.

I posted the details on the Rails wiki:
http://wiki.rubyonrails.org/rails/pages/TestInjector

Or just install it using the plugin manager and take a look at the README file for more details:

script/plugin install http://www.infused.org/svn/plugins/test_injector

or:

script/plugin discover
script/plugin install test_injector

We’re going to see Paul Oakenfold at the Crystal Ballroom tonight. We saw Paul live at Amnesia when we were in Spain a couple of years ago. I never expected to see him come to Portland!

I think about 20 of our friends are going, so it should be a great time.