On my path towards clustering a Rails app on JBoss on EC2, I stumbled across Bryan Kearney and the other Thincrust guys. With their help, I now have a JBoss AS5 + jboss-rails "appliance" ready to roll.

Grab the raw image or the VMWare image, and play along at home.

Fire up the image in your favorite virtualization environment. I give my virtual machine at least a gig of RAM. Marvel at the pretty Grub splash screen, courtesy of James Cobb (JBoss.org designer).

Let it boot on up, and you'll notice a handful of things:

• Very few things roll across during boot. The image is an assembly of "just enough" OS bits.
• Before JBoss boots, "Installing Appliance" or "Updating Appliance" will scroll by. This is the Thincrust magic that allows adjustment of the appliance in a consistent and controlled manner (via Puppet).
• JBoss AS 5 (with rails deployer) starts at boot.

You can login with root password of thincrust.

The login prompt will tell you the IP address of the appliance, since it probably booted off DHCP. JBoss will be up and running at http://<IP_ADDRESS>:8080/.

You can su jboss, whose $HOME is /opt/jboss/jboss-as5, which coincidentally is $JBOSS_HOME. The default configuration is used to start the AS. Logs are under /opt/jboss/jboss-as5/server/default/log/. And to deploy, just drop something into /opt/jboss/jboss-as5/server/default/deploy/ and it'll hot-deploy.

To control the service, as root:

• service jboss stop
• service jboss start
• service jboss status

I'll make the RPMs used to build this available sometime soon. Until then, you can poke around the bits I use to create the RPMs ultimately used by Thincrust to build the appliance image. They are packaged in a way that makes my Red Hat brethren throw up in their mouths a little bit.

Also, once I test'em on EC2, I'll throw out public AMIs for testing.

By no means is this complete. This just marked a nice spike of a milestone along the way. There's still plenty of things that'll poke you in the eye if you're not careful. Always wear your safety harness. Drink plenty of fluids. Keep away from children.

It can sometimes be funny, the paths we take.

Once I'd verified that a Rails app deployed on JBoss would indeed cluster, I sat in my farmhouse, looking at my lone little Mac. Not much of a cluster to play with.

So I started looking at Amazon EC2, which is truly very nice, particularly when paired with Elasticfox.

Of course, firing up a cluster on EC2 requires a nicely-produced, ready-to-boot machine image or a lot of manual configuration on each node.

Sacha pointed me to another group within Red Hat: Thincrust.

Thincrust configures a Fedora disk image with "just enough" OS bits, and provides a way to add/update applications on it. It's a happy mixture of Kickstart, Puppet and Yum.

The goal is to make it easy to produce "appliance" images that could be flung onto machines, real or virtual. Need a Git server? Fire up the Git appliance on the cloud. Need a Drupal server? Fire one of those up. Need a JBoss server or cluster? We're working on that..

Thincrust is built upon Fedora. My Mac is not. But VMWare Fusion lets me run Fedora. So I can create Fedora-based Thincrust images. Which I'll deploy on EC2. Which is running Xen, probably on RHEL. And ultimately allowing you to run your Ruby-on-Rails applications on a Java stack.

There are times I can't remember exactly which OS, language, or virtualization environment I should be thinking in.