fabric

https://github.com/setfire/fabric

Fabric is a small ruby app to perform tasks on servers via SSH. Built around net/ssh and taking heavy inspiration from Capistrano, it currently focuses on managing remote users and their keys on clusters of servers. It does this without the need for a process/daemon/dependency or even ruby being installed on the remote host(s). In the future, it will allow you to create policies for server management and perform sysadmin tasks via a system of recipes.