How to create a shared drive between Amazon EC2 Windows Instances

In theory, that's the idea, but don't host a webserver or anything on it that can't die. This is traditionally used for distributed jobs like data churning, rather than services, since if the spot price goes over your max bid, your server turns off.

Also, just making sure you have your numbers right, it's $0.085 per hour for on-demand, not $0.85. Might make a difference in your projections :)

I took a look at the source code of Jenkins and that's a reasonable fix to it. It won't take much hacking to add the option of selecting which availability zone in a region one wants or to change termination to a simple stop. I think that's the best approach here.

If sufficiently motivated, I might post a patch. Source code is at https://github.com/jenkinsci/ec2-plugin/ if you're handy with Java.