gistfile1.rb

require 'fog'
$connection = Fog::Compute.new({:provider => "Rackspace", :rackspace_username => "xxx", :rackspace_api_key => "xxx", :rackspace_region => :lon})

def get_servers(stage, role)
  $connection.servers.select {|s| s.name =~ Regexp.new("^#{role}\-(.*)\.#{stage}\.buddyapp\.org$")}.map(&:ipv4_address)
end

role :web, *get_servers("staging", "web")
role :app, *get_servers("staging", "app")
role :jobs, *get_servers("staging", "jobs")
role :db, *get_servers("staging", "jobs").first, :primary => true