1. A method, the method comprising: generating, on a computer, a model of an information technology (IT) system that models policies for deploying, configuring, and operating the IT system, the model comprising type declarations in the typing syntax of a declarative language, where the type declarations together model the policies for configuring and operating the IT system, and where the type declarations declare types of classes/components of the IT system, types of relationships between classes/components of the IT system, and constraints of the IT system, wherein the types of classes/components comprise types of hosts, types of servers, and types of applications, and wherein the types of relationships comprise hosting relationships, dependency relationships, delegation relationships, and communications relationships; and storing the model in a computer readable medium.