We've moved to the point where everything developed in the past 12 months is deployed using Puppet and Vagrant. You trigger a build and a pre-configured system materialises either on your desktops or your servers.

The challenge for us has been getting something that happily builds from a single master to something that can build on many hundred machines without a single master dependency.

Technologies like Docker look incredibly promising.

By treating infrastructure as software it means that the full configuration goes under version control!

It's a brave and better new world.