Ubuntu 12.04.1 LTS was released, and that meant it was time to upgrade my Ubuntu EC2 instances from 11.10 to 12.04.1 LTS.
When I logged in via SSH I saw the nag to upgrade and thought, "crap...the last time I did this, I destroyed my EC2 instance". The upgrade went flawlessly this time because I created an AMI first, and after a few days I will delete that AMI and associated EBS volumes.
Step 1: Backup
Create an Amazon Image (AMI) of your existing EC2 instance. If anything fails, you can simply launch the newly created AMI and re-associate your Elastic IP. (You ARE using an Elastic IP, right?)
Step 2: Upgrade
When the AMI is finished, log into your EC2 instance via the terminal and start upgrade:
sudo apt-get update -y && do-release-upgrade