Ubuntu 9.04 Jaunty has reached EOL (End Of Life). It is no longer supported by Ubuntu with security updates and patches. You have known this day was coming for 1.5 years, as all non-LTS Ubuntu releases are supported for only 18 months.
I have no plans to delete the Ubuntu 9.04 Jaunty AMIs for EC2 published under the Alestic name in the foreseeable future, but I request, recommend, and urge you to please stop using them and upgrade to an officially supported, active, kernel-consistent release of Ubuntu on EC2 like 10.04 LTS Lucid or 10.10 Maverick.
I have removed Jaunty from the list of public Ubuntu AMIs at the top of Alestic.com and you can see that we are getting that much closer to having all the main, active Ubuntu AMIs created by and officially supported by Canonical (and not me). Yay!
If you are running on EC2 with Jaunty, I believe the cleanest way to upgrade to Lucid or Maverick would be to start a new instance (preferably EBS boot) with the latest AMI from Canonical, apply your software installation and configuration changes, and copy your data over from the old instance. Since Jaunty was never officially supported by Canonical on EC2, it was using non-standard kernels and init software, so an in-place upgrade is not likely to go smoothly.
Don’t terminate your old instances until you’re sure you have everything functioning on the new ones. EC2 is fantastic for use-cases like this where you can double your hardware temporarily for low cost.
Farewell Jaunty, you served us well.