Register automatically an ec2 instance to route 53. The domain is pushed with DHCP option and is stored in the resolv.conf file

register_ec2_to_route53.py

#!/usr/bin/env python

import urllib2
import boto
import logging
import socket

logger = logging.getLogger(__name__)
handler = logging.FileHandler('/var/log/route53.log')
formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler) 
logger.setLevel(logging.INFO)

# Use the first domain of resolv.conf as main domain to find route 53 zone
resolv = '/etc/resolv.conf'
look_for = 'search'
hostname = socket.gethostname()
domain = None

local_ipv4 = urllib2.urlopen('http://169.254.169.254//latest/meta-data/local-ipv4')
ipv4 = local_ipv4.read()

with open(resolv, "r") as file_to_read:
    for line in file_to_read:
        if look_for in line:
            resolv_array = line.split()
            domain = resolv_array[1]

conn = boto.connect_route53()

try:
    zone = conn.get_hosted_zone_by_name(domain)
except DNSServerError:
    logger.error('Zone Not Found')
    sys.exit(1)

from boto.route53.zone import Zone
vpc_zone = Zone(conn, zone['GetHostedZoneResponse']['HostedZone'])
if vpc_zone.find_records(hostname.lower() + '.' + domain + '.', 'A', 1, True):
    logger.info("Entry %s already exists" % (hostname.lower() + '.' + domain + '.'))
else:
    vpc_zone.add_a(name=hostname.lower() + '.' + domain + '.', value=ipv4, ttl=300)
    logger.info("Adding entry: %s A %s" % (hostname.lower() + '.' + domain + '.', ipv4))