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Stan
Asked: 2013-10-11 08:38:01 +0800 CST

Amazon EC2 instance cannot resolve hostnames

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My free tier EC2 instance (ubuntu 11.04, created last year) is expired. I just created a new one (ubuntu 12.04), but found that the new EC2 cannot resolve any hostname. By checking /etc/resolv.conf.

The old one looks like:

domain ap-northeast-1.compute.internal
search ap-northeast-1.compute.internal
nameserver 172.16.0.23

Where the new one looks like:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

Is the nameserver configuration not automatically set up now? How should I configure the nameserver, through the AWS console? Do I have to use Route 53? I would rather use a free solution if it's not too complicated to set up.

amazon-ec2

3 Answers

  1. Best Answer

    I was curious so I just launched an instance using AMI "Ubuntu Server 12.04.2 LTS" and I have this in resolv.conf: 

    # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 172.16.0.23
search us-west-2.compute.internal

    So maybe something went wrong when you created your instance. Try launching a new one.

    Edit: Since your instance is inside a VPC, try Creating a DHCP Options Set with domain-name-servers=AmazonProvidedDNS, then assign the options set to your VPC.

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  2. Here's what I appear to have observed: when I skipped the configure steps in the Create Wizard, my instance had an empty resolv.conf, but when I clicked through the steps (didn't change the defaults, just clicked through dutifully), then the resolution configuration had the nameserver in it.

    • 3

  3. Change the DNS options for your VPC. http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_DHCP_Options.html You can add your private DNS there, and instead of adding the AWS DNS server, the DHCP update will put the addresses you have configured.

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