gistfile1.txt

#!/usr/bin/env ruby
require 'aws-sdk'
require 'net/http'
 
AWS.config({})
 
hostname = ARGV[0].to_s
domain = 'i.domain.com'
zone = ''
ttl = 60
 
metadata_endpoint = 'http://169.254.169.254/latest/meta-data/'
hostname_local = Net::HTTP.get( URI.parse( metadata_endpoint + 'local-hostname' ) )
hostname_public = Net::HTTP.get( URI.parse( metadata_endpoint + 'public-hostname' ) )
 
records = [{
  :alias => [ hostname, domain, '' ] * '.',
  :target => hostname_local
},{
  :alias => [ hostname + '-public', domain, '' ] * '.',
  :target => hostname_public
}]
 
#update DNS records
rrsets = AWS::Route53::HostedZone.new(zone).rrsets
records.each{ |record|
  rrset = rrsets[
    record[ :alias ],
    'CNAME'
  ]
 
  if rrset.exists?
    rrset.delete
  end
 
  rrset = rrsets.create(
    record[ :alias ],
    'CNAME',
    :ttl => ttl,
    :resource_records => [
      { :value => record[ :target ] }
    ]
  )
}