Over the past year, I've read a lot about how teams are deploying their software. I've known for a while that Google has the ability to roll out new code to a small percentage of their servers and ramp up the breadth of deployment if they like how the software is behaving.
Lately, I'm starting to see more and more teams implement that sort of functionality. Rick Olson describes how GitHub implements it in How we deploy new features, and includes links to how Forrst and Flickr do it as well. At Velocity, Paul Hammond explained how to build an application-specific kind of version control into your app.
I'm a little surprised that few libraries have emerged for managing this. It would seem that, given all the excitement about continuous deployment, automated rollbacks, and incremental rollouts, someone would come up with something that they think is neat enough to share. I suspect that in fact, this is a really ugly, deeply application-specific sort of thing, no one likes to look at how they do it, and that's why there is plenty of talk about how to do it, but no libraries making it a simple thing.
