May 27, 2013

Free DNS Servers on Amazon Web Services (AWS)?

Filed under: Networking,T3city — pj @ 7:47 pm

Recently, I was researching how to run Ubuntu instances on AWS. I found The free tier includes 750 hours for EC2 Linux Micro Instances and 30GB of EBS storage. After clicking around, I figured out this is what you get with the Micro EC2 Instance running Ubuntu 12.04 LTS:

  • The default Ubuntu 12.04 LTS AWS image boots on a 8GB  root partition created on EBS. This allows you to run a a normal Ubuntu server. If you create a larger EBS partition, Ubuntu will automatically expand the file system on first boot, but 8GB should be plenty for a typical DNS server.
  • The Micro Instances includes 600MB of RAM
  • I thought I read that the Micro Instance includes 2 CPU cores, but the image I booted only shows 1 CPU.

This should be fine for a backup DNS server.

The AWS documentation is large and intimidating. In the past, AWS encouraged a lot of specialized AWS development to create paravirtualized kernels that worked under Xen combined with VM instances that booted up and automatically configured  themselves to use S3 storage. This is a great model for web sites and other Internet based services that require scaling across many nodes, it seemed like overkill for something like DNS that typically only requires a couple of high availability servers. Fast forward several years later and now AWS lets you easily create VM backed by EBS storage that can be managed like a typical server. Here are the steps I followed to create my AWS based DNS server:

  1. Opened an AWS account  - credit card is required (!)
  2. Configure and start a new Ubuntu 12.04 LTS micro instance. The free instance is clearly identified and the defaults end up with an EBS backed server with a 8GB root partition.
  3. Add a public IP address:
  4. Login to the new instance with the AWS generated SSH key pair:
  5. Configure your new instance normally

Now we just have to wait and see if it is really free!

One Response to “Free DNS Servers on Amazon Web Services (AWS)?”

  1. pj says:

    After about 6 months, I received an “abuse” notice from AWS. It turns out that they don’t allow running recursive DNS servers. I use recursive DNS to test things out, but it was no big deal to disable it.

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