Paul Dowman

UPDATE: it’s 0.9.8.1 now, there was a small update to the RubyGem. The new gem uses the same AMI’s.

EC2 on Rails version 0.9.8 is now available (or will be in a few hours when the RubyForge servers are synced). This is a recommended update for everyone.

It includes some major new features:

• monit monitoring daemon: monitors mysqld, apache, memcached, mongrels, system load and free drive space
• incremental MySQL backup (important for large databases)
• Apache SSL support
• a local Postfix SMTP server enabled by default

And most importantly this fixes the problem with broken Ubuntu package updates which was caused by a missing repository in the list of repositories.

As I mentioned yesterday, the base image is now built using Eric Hammond’s EC2 Ubuntu script.

Also, there are major new features such as incremental MySQL backup (important for large databases), Apache SSL support, and a local Postfix SMTP server enabled by default.

My priorities now are:

1. Release an update based on Ubuntu 8.04 Hardy (this version is still using Ubuntu 7.10 Gutsy because I wanted to provide a reliable update as quickly as possible due to bug #20040. But now that the base image is built with Eric Hammond’s script it should be easy to update to Hardy.)
2. Create complete documentation.
3. Release a 100% bug-free version 1.0 with the current feature-set. Please help by reporting any bugs you find, either using the RubyForge bug tracker or by email.

The point of EC2 on Rails is to save other people from duplicating the effort of building and configuring a Rails server on EC2. When I started it there were no other public Ubuntu server image projects so I had to start from scratch. I had to write a build script to build an Ubuntu image, patch the Amazon AMI tools to work on Ubuntu, etc., before I could even begin to create the Rails-specific stuff. And every 6 months there’s a new version of Ubuntu and I have to do at least some of that over again.

But in the meantime Eric Hammond has created an excellent Ubuntu AMI base install project, it has all the necessary features like installing the AMI tools, getting the public keys on first boot so that you can log in with your EC2 account’s private key, regenerating the ssh host keys on first boot, etc. And it has some cool new features like the ability to give an instance an arbitrary script on startup using EC2’s “user-supplied instance data“. And, it has an active community.

So why would I duplicate that effort?! I’d rather concentrate on improving the Rails-specific features, so I’ve adapted my build script to be run from Eric’s. And by “adapted”, I mean “took out tons of stuff that I no longer need to care about”! And when I want to make any improvements that aren’t Rails-specific, I can contribute them to Eric’s project where they’ll benefit more people.

If you’re building your own custom AMI, I highly recommend using Eric’s base install script. You’ll end up with a solid base for your image with way less work, and it has a hook to easily include your own build script to customize the build.

Version 0.9.8 of EC2 on Rails uses Eric’s script for the base install, and it will be released in a couple of days (I’m using it in production already).

Seriously, why reinvent the wheel? You gotta love open source!

I’ve been working hard on EC2 on Rails, version 0.9.5 is now available. Since my last post here there have been some major changes:

Capistrano tasks

There is now a rubygem available that provides Capistrano tasks to manage the instance. There are tasks to set the server’s timezone, install packages and rubygems, backup, restore, create and delete the database, set the MySQL root password, and more. To use these in your Rails project type:

> sudo gem install ec2onrails

Put Capfile in the root of your rails folder, and put deploy.rb in the config folder.

Then, from the root of your project type:

> cap ec2onrails:setup

This automatically sets your server’s timezone, installs any custom rubygems and Ubuntu packages, and creates your database for you. You can now deploy your rails app as you normally would:

> cap deploy:migrations

Another useful task for testing is:

> cap ec2onrails:restore_db_and_deploy

This recreates the database, restores data from an S3 bucket (specified in your deploy.rb), and deploys the app. I use this to prepare a staging server with the current production data and current production version of the app. After running this task I have an exact copy of my production server. I then deploy the latest version to this server before deploying it to production. This is a good way to be really sure your production deployment won’t fail (especially your migrations).

To see a list of all available Capistrano tasks:

> cap -T

New Ubuntu version

It’s now built with Ubuntu 7.10 “Gutsy”.

Support for new instance types

There are both i386 and x86_64 versions available to support the new EC2 instance types. So you can now use large and extra-large instances.

Multiple instances

The earlier versions only worked if your rails app was running on a single server. That was lame! Now you can have multiple instances using any combination of these roles: web server, app server, primary database. I’m working on adding a MySQL slave role and eventually a Memcache role.

For full instructions and details see the project web site.

Just a couple of announcements about my Ruby on Rails server image for EC2:

New version

There is a new server image with some minor changes and bug fixes. For details see the change log. I’ll keep the old image around for a while.

Mailing lists

I have created two Google groups, one for announcements only (new versions, etc.), and one for general discussion.

Ongoing work

I’m working on a build script so the image can be built from source. Then I will provide access to a subversion repository with the source. Some people have expressed an interest in contributing, which I’m really happy about! If you want to get involved, please join the mailing list!

Need to set up a Ruby on Rails server? So do I, and chances are you need almost the same configuration as me. As of this writing 1845 people have bookmarked Coda Hale’s excellent guide to setting up Mongrel + Apache on del.icio.us. The article has 187 comments. Why should so many people each have to do the same thing?

The answer is a Rails server virtual appliance, and I’ve made one for Amazon’s EC2 hosting service.

A server is no longer a physical thing, and EC2 takes it one step further: they completely separate the concept of server images and instances. An image is like a snapshot of a server hard drive, stored in an unchangeable state in their S3 data storage service. An instance is a running server that was booted from a copy of this image. But the instance is transient; changes to it’s own working copy of the image don’t affect the original image that it was booted from, and because of this multiple server instances can be started from the same image. (Hence the “elastic” property, new instances can be created on demand, your server pool can grow and shrink dynamically.)

Now even the OS can be configured and tested once, and then simply deployed as part of the application. So how is that different from any of the third-party libraries and frameworks that we use as part of our applications? I assemble applications out of many pieces of third-party software. All of it is continually improved by other people, none of it requires painstaking building or configuration, and the OS can be used the same way.

So I’m going to continue working on my Ruby on Rails EC2 server image with the goal that you will be able to simply deploy your Rails app directly to it with Capistrano with little or no configuration.

Try it out, and tell me what you think!