One of the issues that I have run into several times is the securing of access to server farms. You generally end up with a ton of keys laying around and it gets really messy. At one of my past jobs, they had written a pretty killer tool that gave me the springboard for pssh. Pssh is cool because it knows what servers you have by interrogating the AWS APIs, what keys they need and even what their internal DNS name is in your cloud.
So, enter pssh, the Proxy Secure SHell! a SSH automation tool suitable for use as bastion ssh server, or general hand holder. At this time, only works on AWS. Since it’s built on the killer @fog gem, it can be easily expanded to just about any cloud provider.