1. A cloud service, comprising: an API (application programming interface) as tangibly embodied in a set of computer-executable instructions on a computer on a network, said API providing a user interface for a cloud environment comprising one or more virtual machines to be selectively instantiated on at least one computer in said network upon a user request; and a library accessible via said API, said library providing definitions of components available to be instantiated in said cloud environment, wherein said API automatically instantiates an image of a virtual network of components as defined by a user input request and provides at least one cloud portal providing said user an access to exercise said instantiated virtual network image.