Updated Route53 Record When EC2 Instance Starts

update-dns.rb

# /home/ubuntu/bin/update-dns.rb

require 'rubygems'
require 'open-uri'
require 'route53'

zone = "bartimae.us"
record_type = "A"
ip_address = open("http://169.254.169.254/latest/meta-data/public-ipv4") { |f| f.read }

begin
  conn = Route53::Connection.new(ENV['AWS_ACCESS_KEY_ID'], ENV['AWS_SECRET_ACCESS_KEY'])
  conn.get_zones(zone).first.get_records(record_type).each {|record| record.update(record.name, record.type, record.ttl, [ip_address])}
  puts "DNS Updated for #{zone}"
rescue RuntimeError
  puts "Error accessing Route53 with supplied credentials"
end

update-dns.sh

#!/bin/bash

su - ubuntu -c "ruby $HOME/bin/update-dns.rb"


# file location: /etc/init.d/update-dns

Run /etc/init.d/update-dns when EC2 instance boots with sudo update-rc.d update-dns defaults