chef_hostname.rb

#include_recipes
include_recipe "route53"

# Translate the role into a shortname.
role_trans = {
  "memcached" => "mc",
  "wordpress" => "wp",
  "rails" => "rails",
  "lb" => "lb",
  "monitoring" => "mon",
  "chef-server" => "ops",
  "ci" => "ci",
  "openvpn" => "vpn",
  "rundeck" => "deploy",
  "log" => "log",
  "sensu" => "sensu",
  "database" => "db"
}

#determine system roles
$hnroles = Array.new
node[:roles].each do |i|
  if role_trans.include?(i) then
    $hnroles << role_trans.fetch(i)
  end
end 

#set host_fqdn to ec2 instance id - roles . ctothex.com
shortname = node['ec2']['instance_id'] + "-" + $hnroles.sort.join

domain = "myawesome.com"

host_fqdn = "#{shortname}.#{domain}"

#Find monitor nodes
mnodes = Hash.new
search(:node, "role:monitoring AND chef_environment:#{node.chef_environment}") do |n|
  mnodes[n.fqdn] = { 'address' => n.ipaddress,
                      'fqdn' => n.fqdn,
                      'hostname' => n.hostname }
end

file "etc_hostname" do
  path "/etc/hostname"
  mode 0444
  owner "root"
  group "root"
  content "#{host_fqdn}\n"
  notifies :run, "execute[hostname]", :immediately
end

template "etc_hosts" do
  path "/etc/hosts"
  source "hosts.erb"
  owner "root"
  group "root"
  mode 0444
  variables(
    :fqdn => host_fqdn,
    :shortname => shortname,
    :mnodes => mnodes
  )
end

template "etc_resolv" do
  path "/etc/resolv.conf"
  source "resolv.conf.erb"
  owner "root"
  group "root"
  mode 0444
  variables(
    :domain => domain
  )
end

execute "hostname" do
  command "hostname -F /etc/hostname"
  action :nothing
end

route53_record "create a record" do
  name "#{host_fqdn}"
  value node['ec2']['public_hostname'] 
  type "CNAME"
  ttl 300
  zone_id YOURAWSR53ZONEID
  aws_access_key_id REFERNCEYOURAWSID
  aws_secret_access_key REFERENCEYOURAWSKEY
  action :create
end