Friday, December 23, 2011

Amazon EC2 reserved instance - one year later

My first Amazon Web Services EC2 reserved instance, which supports the Naval Reactors History Database online resource, expired today. This is something of a milestone for me. I had used EC2 instances for several months prior to purchasing a reserved instance last December. This reserved instance enables me to run an EC2 instance 24/7/365 at a reduced cost over what I would pay for an on-demand AWS EC2 instance.

Based upon my year's experience, I have these thoughts:
  • First, my goal is to maintain the nrhdb resource online at the lowest possible cost. While it would be possible (though technically clunkier) for me to run the nrhdb on a Windows server, the EC2 prices for Linux versus Windows make it clear that the purchase and use of a Linux EC2 reserved instance is the most cost-effective choice.

  • Second, the Amazon Web Services outage that occurred in April made me take a second look at the way that I manage my instance's data. I posted on this incident earlier this year. I now maintain a copy of my server's volume in another availability zone in the East region at all times and update the snapshot/volume every week or so. Although I could use EC2 API tools to automate this process, I'm still doing it manually using the AWS Management Console.

  • I wound up changing my server OS during the year from Fedora to Amazon Linux (using the Amazon Linux AMI). Overall, my experience with this AMI has been positive - the Amazon Linux instance comes with fewer preinstalled packages and the ongoing installation of updates is very seamless.

  • Finally, EC2 reserved instances are not only specific to an AWS region, but to an availability zone as well. Thus, you're locked into that AZ for the term period. Which can be a problem if, for example, there's an incident like the one that impacted the East region, but was centered in one availability zone.
Overall, I'm glad that I'm using Amazon Web Services EC2 and I believe that I'm getting a good value from AWS as a whole. The EC2 home page notes that EC2 "is designed to make web-scale computing easier for developers" and that is certainly my take on it. I've been able to maintain an online service reliably for a year and the purchase of the reserved instance has made it affordable.