Introduction to Rubber

Rubber is a Capistrano plugin that makes it easy to deploy Ruby on Rails applications to Amazon’s Elastic Compute Cloud.

To get started, determine the HTTP server, the app server, and the database you’ll want to use when running your Rails app in production. You can view the list of supported stacks here.

Rubber Stack Templates

Rubber already provides some templates for common stacks like complete_passenger_nginx_postgresql, complete_passenger_mysql (which includes Apache as the HTTP server), and complete_unicorn_nginx_postgresql.

You can also create your own stack. To do this, look at a template you like, and use its components to build your own stack. For example, in complete_unicorn_nginx_postgresql, you’ll see the templates.yml file. Open it and you’ll see it’s based on two templates: complete_unicorn_nginx and postgresl. The complete_unicorn_nginx template itself is based on the following templates: base, nginx, unicorn, monit, collectd, and graphite. Monit, collectd, and graphite aren’t necessary for production, but they do make monitoring server statuses and site data much easier.

The absolute minimum stack for production must include an HTTP server, an application server, and a database (unless your Rails app doesn’t use a database at all). Thus, the following templates will suffice:

  • base
  • nginx
  • unicorn
  • postgresql

Installing Rubber in your Rails app

To install Rubber in your Rails app, go to the Gemfile and add

gem 'rubber'

Do a bundle install to download and install the gem. Next, go to the root of your Rails app and install all the templates you’ve chosen for your app.

> rubber vulcanize base
> rubber vulcanize nginx
> rubber vulcanize unicorn
> rubber vulcanize postgresql

As you can see, I’ve chosen to custom tailor the stack. If you’re just starting out with Rubber, and your primary goal is to put your Rails app in prod, you can use one of the complete stack templates like so

> rubber vulcanize complete_unicorn_nginx

For my own Rails apps, I tend to stay away from the complete templates that Rubber provides by default because I don’t want to use collectd and graphite.

Configuring Rubber

Now that we’ve installed Rubber in our Rails app, it’s time to configure it. The first file to look at is config/rubber/rubber.yml

app_name: supercoolrailsapp
app_user: supercoolrailsapp
timezone: US/Pacific
    region: us-west-1
    key_name: supercoolrailsapp-keypair
    image_type: m1.small
    image_id: ami-42b39007 # Ubuntu 12.10 Quantal instance-store

I’ve left out the useful comments that rubber.yml is generated with, but it’s generally a good idea to keep them to help you navigate and understand each configuration. Most of the configuration is pretty self-explanatory, so I won’t go into much detail here.

As you can see, I’ve named the app supercoolrailsapp with app_name. This name doesn’t have to be the name you selected for your app when you first created your Rails app. The app_user can also be any name you want. I got the image_id (an AMI id) from Alestic. Make sure you choose an AMI from the AWS region you’ve specified; otherwise, your deployment will fail.