Abstract: Customers of a computing resource service provider may transmit requests to instantiate compute instances associated with a plurality of logical partitions. The compute instances may be executed by a server computer system associated with a particular logical partition of the plurality of logical partitions. For example, a compute service may determine a set of server computer systems that are capable of executing the compute instance based at least in part on placement information and/or a diversity constraint of the plurality of logical partitions.

Abstract: A provider network determines which servers to use to host a group of virtual machines for a customer. A placement manager within the provider network employs a placement technique which prioritizes spreading virtual machines for the customer across different “subzones.” A subzone is a logical division of a provider network's hardware and/or software denoting risk boundaries. By placing virtual machines in separate subzones, the customer's virtual machines and thus the task collectively performed by the virtual machines are less impacted by a failure within one of the subzones.