1. A method for planning the execution of one or more plans in a virtualized computing environment, the method comprising: computing an order for execution for one or more plans, and the corresponding operations in said one or more plans; validating whether a plan and the corresponding operations for the plan may be successfully executed, prior to executing the plan and the corresponding operations; executing the plan and the corresponding operations, in response to a successful validation; and aborting execution of the plan and the corresponding operations, in response to an unsuccessful validation, wherein the validating process takes into consideration impact of other plans that are previously validated and possible changes in the computing environment since time the plan was computed.