I want to run a micro instance on EC2 that will serve as a proxy server for my GAE app. I found this article on how to run it on ami-ad7e2ee8:
http://blog.magicalhobo.com/2011/04/11/running-a-reverse-proxy-for-app-engine-on-amazon-ec2/
but that ami seems to be no longer available. Can someone tell me which free-tier ami to use if I want to easily make a proxy server like that, or if it is impossible this way, what other way can I run a proxy server as a free EC2 instance (a step-by-step tutorial would be welcomed)?
The procedure outlined in that article essentially amounts to changing your DNS settings to point your domain at the EC2 instance, and running Nginx (a webserver) on that EC2 instance, with it proxying requests to Google Apps. This general idea can be applied to almost any AMI. I would recommend using the 32-bit version of Amazon's Linux AMI (ami-7f418316) for the purpose (it works in the free tier, and is optimized for good performance. It is based on RHEL/CentOS, so you would would change the following lines:
Into:
The remaining instructions remain essentially the same (although, I don't believe the 'sites-available' is created by default, and the main nginx config file is in /etc/nginx/nginx.conf).
As an aside, if you use the AWS console to launch your instances, you will note a yellow star beside instances that are eligible for use in the free tier. Any of them should work fine for this purpose, although, the simplest ones (i.e. ones that have not been pre-loaded with an assortment of unnecessary software) would be the best suited to your purpose.
If you do wish to stick with an Ubuntu AMI, you can find the official list at Ubuntu's EC2 Starters Guide. This lists ami-f333fe9a as the current Ubuntu 10.10 32-bit AMI (which is eligible for the free tier), although, you may prefer to use 32-bit Ubuntu 11.04 instead (ami-e358958a).