1. A method, implemented at a computer system including one or more processors, for optimized provisioning of virtual machines, the method comprising: identifying a plurality of jobs that are currently being processed by a virtualized compute infrastructure that includes one or more virtualized computing providers, the virtualized compute infrastructure comprising a plurality of currently provisioned virtual machines; identifying, within a queue, a plurality of jobs to be processed by the virtualized compute infrastructure; for each of at least one of the plurality of jobs within the queue, performing at least the following: processing metadata associated with the at least one queued job, the metadata comprising logical data describing processing requirements of the at least one queued job; based at least partially on the processed metadata, selecting at least one virtual machine to be used for processing the at least one job, selecting the at least one virtual machine comprising at least: analyzing configuration types of one or more available virtual machines associated with at least one of the one or more virtualized computing providers to identify each available virtual machine that meets the processing requirements of the at least one queued job, the one or more available virtual machines not currently being provisioned for processing jobs; analyzing the plurality of currently provisioned virtual machines to identify each currently provisioned virtual machine that both meets the processing requirements of the at least one queued job and is idle or will soon be idle; and selecting the at least one virtual machine to be used for processing the at least one job from the one or more available virtual machines associated with at least one of the one or more virtualized computing providers and the currently provisioned virtual machines that meet the requirements of the at least one queued job and are idle or will soon be idle; and provisioning the at least one selected virtual machine for processing of the at least one queued job.