Running the Show: Configuration Management with Chef - RailsConf Tutorial
Few completed Rails apps are architecturally simple.
As soon as you grow, you find yourself using multiple subsystems and machines to scale. Cloud-based environments such as EC2 make this an attractive and cost-efficient option, but create new headaches in configuration management.
Chef is the latest development in open source systems integration, a powerful Ruby-based framework for managing servers in a way that integrates tightly with your applications and infrastructure. As developers become increasingly responsible for operations, Chef lets you manage your servers by writing code, not running commands.