1. A service request routing system comprising: a model table configured to store resource models; a monitor coupled to said model table and programmed both to model resource consumption in a service providing infrastructure, and also to store said modeled resource consumption in said model table; and, a router coupled to said model table and programmed to route each service request to a corresponding service instance disposed in an associated service host having a service providing infrastructure based upon a matching of resource components of said service providing infrastructure to a resource model for said service request.