Have Route 53 point to an instance instead of an IP or CNAME?

Question

We're using Route 53 DNS to point to an EC2 instance. Is there any way to get Route 53 to point to the instance directly, instead of to an Elastic IP or CNAME?

I have multiple reasons for this:

1. I don't want to burn an IP.

2. CNAMEs are unreliable, because if an instance goes down and comes back up, the full name, ec2-X-X-X-X.compute-1.amazonaws.com, will change.

3. In the future, I need to spin up instances programmatically and address them with a subdomain, and I see no easy way to do this with either elastic IPs or CNAMEs.

What's the best approach?

Answer 1

I wrote my own solution to this problem since I was unhappy with other approaches that were presented here. Using Amazon CLI tools is nice, but they IMHO tend to be slower than direct API calls using other Amazon API libraries (Ruby for example).

Here's a link to my AWS Route53 DNS instance update Gist. It contains an IAM policy and a Ruby script. You should create a new user in IAM panel, update it with the attached policy (with your zone id in it) and set the credentials and parameters in the Ruby script. First parameter is the hostname alias for your instance in your hosted zone. Instance's private hostname is aliased to <hostname>.<domain> and instance's public hostname is aliased to <hostname>-public.<domain>

UPDATE: Here's a link to AWS Route53 DNS instance update init.d script registering hostnames when instance boots. Here's another one if want to use AWS Route53 DNS load-balancing in similar fashion.

Answer 2

If you stick to using route53, you can make a script that updates the CNAME record for that instance everytime it reboots.

see this -> http://cantina.co/automated-dns-for-aws-instances-using-route-53/ (disclosure, i did not create this, though i used it as a jumping point for a similar situation)

better yet, because you mentioned being able to spin up instances programmatically, this approach should guide you to that end.

see also -> http://docs.pythonboto.org/en/latest/index.html