1. A method for virtualizing a plurality of computers in a data center, the computers being connected to a network having a network topology, the method comprising: creating a backup image of each of the computers; saving together with each backup image, supplemental to each backup image, configuration information of the corresponding computer, the configuration information comprising persistent and volatile state; creating each backup image as a snapshot of the corresponding computer, the snapshot comprising an application-consistent image as of a specific point in time of primary storage of the computer; saving together with the configuration information saved with the backup image, information representing the state of the network connections of the computer; loading the backup images as a cloud computing node; and loading the saved information regarding network connections together with the backup images, and using such information to recreate the network connections of each such computer.