I'd like to use Ruby 2.0 on Amazon OpsWorks, so I'm trying the following:

Choose custom cookbooks and set them to my fork of https://github.com/aws/opsworks-cookbooks
Update all version numbers here https://github.com/aws/opsworks-cookbooks/blob/master/ruby/attributes/ruby.rb to 2.0 values.

This doesn't seem to have any effect, though.

Do custom cookbooks override their built in counterparts?
Does OpsWorks use the Ruby recipe from the cookbook for basic Ruby setup?
The same question applies to Nginx too - can I control versions and settings by changing my fork for the cookbooks?

OpsWorks now fully supports Ruby 2.0, in Layer settings you can specify the version of Rails, Bundler and Rubygems.

Opsworks already has support for Ruby 2.0, it's just not exposed through the UI. However, you can easily enable it by simply passing in the following custom JSON

{
  "opsworks" : {
    "ruby_version" : "2.0.0"
  }
}

That's it! No need to install any custom packages or anything.

OpsWorks distributes some of their packages their own and Ruby 2.0 is not part of it right now. If you want to use Ruby 2.0 you have to install it your own.

Best, Daniel

Deploy ruby 2.0 with rails 4.0 on AWS opsworks