Get ec2 name from instance without public ip

Question

I'm trying to automate my dns in my ec2 VPC. What I want is:

1. VPC boots up
2. VPC gets instance info from http://169.254.169.254/latest/meta-data/
3. VPC looks up Name tag for instance
4. VPC sets hostname to this tag value, and puts that hostname into Route53 for dns resolution

My problem is with #3 on private instances. ec2-describe-tags hits ec2.amazonaws.com, and this fails when my machine is private.

Is there any way for a private ec2 instance (as in, has no public ip address) to get the name value so I can have this configure things?

Answer 1

Why does ec2-describe-tags fail when you're in a private subnet?

It should route the request out of the NAT instance, assuming you've set one up in a public subnet, and added it as the 0.0.0.0/0 route in the private subnet route table.

See the VPC NAT documentation for more information: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_NAT_Instance.html