1. A method comprising generating a Concrete Model, said Concrete Model describing a structure of resources implementable over a computing utility infrastructure, and satisfying a set of service requirements, said step of generating comprising the steps of: obtaining a Service Environment Model of a service environment, said Service Environment Model describing a set of requirements on a new desired state of said service environment; getting an Infrastructure Model describing both resources and an organization of the resources in the computing utility infrastructure, said Infrastructure Model is encapsulated in a knowledge subsystem; and forming the Concrete Model describing a resource structure such that said Concrete Model refines the Service Environment Model and is mappable to said knowledge subsystem.