A dynamic resource allocation method and system. The method includes the steps of preparing a plurality of instances in different preparation states; receiving a request on a dynamic scheduling condition from the client computer; and launching some of the plurality of instances in the different preparation states in such a combination that the dynamic scheduling condition is satisfied. The method includes computer apparatus for accomplishing the above method. A tangible storage medium includes program steps which, when executed by computer apparatus, causes the computer apparatus to perform the above method.