Cluster SSH, or its OSX incarnation CsshX are great tool to quickly connect to a collection of machines and issue interactive commands in parallel. You just configure them with a collection of machines called 'clusters', set your .ssh/config correctly for all those boxes and voila, you are now in the matrix.

The problem arise when you run your stuff on Amazon's AWS on EC2 dynamic instances. It's impossible to know at a given time which instances are effectively running, and it makes your cssh (or CsshX) configuration useless.

The good news is, Amazon provides an API to access …