The Problem

Day Zero: The Zombie apacalypse wipes out the one of your data centers. Thats cool, we got Availability Zone redundency to beat the bad. Day Two: Zombies take over the region, internet availability goes black. Day Three: The “.com” TLD is no longer resolved.

Well, if you want high availability, I’m talkin Day 2 and Day 3 Zombie Apacalypse availability, then look no further than RT53, Amazons “elastic” DNS server.

Below should provide you with enough information to make certain that your site is the last one to go down as society unravels into a chaotic dystopian nightmare.

The Solution

Get your domain pointing to AWS

You have a domain registered, right? If not, go get one…and don’t use GoDaddy for pete’s sake! Use..like…like gandi.

Okay cool. So open your domain registrar in one tab and RT53 in the other.

In the AWS Console, navigate ServicesComputer & NetworkingRoute 53

Click “Create Hosted Zone” in the Route 53: Hosted Zones view

Add the “Domain Name:” and a pithy comment.

Create the zone, and then ticket the checkbox next to the new domain if it is not already. In the right column of the table, you should see the “Hosted Zone Details”. Find the “Delegation Set” (see image). Note those name servers, and enter them into your domain registrar where applicable. Amazon will be given authorization to server requests to your domain name.

Stop.

Quiet for a second.

Take a moment to admire Amazon’s Zombie Apacalypse awareness. Four name servers, four different top level domains. When dot-com falls, who you gonna calls? Amazon. Jeff Bezos. Smart dude.

“A” Record for the whole world to see

By default you get two records when you create your domain.

  1. The “SOA” (Start of Authority) record says “Amazon is handling resolution and request of this here domain”

  2. The “NS” (Name Servers) record says “These exact nameservers are responsible for this domain.”

Next we add an “A Record”, or Address Record, which response the DNS host/domain name to an ip address.

Click “Create Record Set”

Name
enter subdomain if applicable or leave blank
Type
A - IPv4 Address
Alias
Yes
Alias Target
Select a target, I am using my Elastic Load Balancer from the previous blog entries, so I select that (see below).
Routing Policy
Simple
Evaluate Target Health
No

Now click “Create”.

You should now have a record of type A in your Record Sets. Furthermore, if you have your EC2, ELB running, your domain should resolve to a running application.

Success! Ain’t life grand? ### Conclusion ###

Using Amazon’s RT53 is a natural fit for anyone using the AWS infrastucture. Part 1 show’s us how easily it is to get rockin with Amazons elastic DNS service.

In part two we discuss adding a second load balancer, with health checks and failure over.



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Published

31 March 2014

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