1. A method comprising: receiving an input, associated with a change request, which describes a revision to at least one of a plurality of instances in a model of an actual physical distributed system that comprises an application layer and a host layer, wherein: an instance, of the plurality of instances, comprises an instantiation of a type that comprises property values and relationships in the model of the distributed system and comprises an associated version history that links each version of an instance to a change request; an instance, of the plurality of instances, comprises associated code that allows a state of an instance to affect a configuration of the model of the distributed system; the plurality of instances form an instance space which describes a configuration of the model of the distributed system wherein the plurality of instances comprise one or more hosting relationships that allow for identification of one or more bindings between the application layer and the host layer; and the revision pertains to a change to the at least one of said plurality of instances; and synchronizing the model with the distributed system such that the revision, when applied to the model, is propagated to the distributed system to thereby change the distributed system.