1. A system, comprising: one or more memory units; and one or more processing units coupled to the one or more memory units, the one or more memory units including executable instructions that upon execution by the one or more processing units cause the system to: access a request from a particular entity for an instantiation of a virtual machine on one of a plurality of host computing systems; determine a probable virtual machine lifetime for the requested virtual machine, the probable virtual machine lifetime comprising a probable amount of time the requested virtual machine will be operational; access host status data indicating one or more current virtual machines that are currently operational on each of the plurality of host computing systems and a current lifetime of each of the current virtual machines; determine, based at least in part on the determined probable virtual machine lifetime and the host status data, a particular one of the host computing systems on which to instantiate the requested virtual machine from the entity; and instantiate the requested virtual machine on the determined host computing system.