1. A system for the description, deployment and management of composite applications, the system comprising: a processor; a memory device coupled to the processor; a solution descriptor, stored on the memory device, comprising a set of component workload units, a component workload unit describing a deployable application component with application binary, configuration parameters and dependency declarations; an environment descriptor, stored on the memory device, specifying a set of target platforms and plugins in an execution environment; and a deployer running on the processor, and operable to generate, based on the solution descriptor and the environment descriptor, a list of tuples comprising compatible workload-plugin-platform combinations, the deployer further operable to determine an execution order for the list of tuples, the deployer further operable to invoke the plugins in the list of tuples in the execution order, each of the plugins executing a corresponding compatible component workload unit on a corresponding compatible target platform specified in the list of tuples, wherein the set of component workload units comprises an instance of a component application type in a set of component application types, and the set of component application types is extensible.