Scheduling virtual machines using user-defined rules

A processing device receives a rule for execution by a rules engine and provides the rule to the rules engine. The processing device receives a request to provision a virtual machine (VM) having VM attributes. The processing device provides metrics of a plurality of physical hosts to the rules engine and the VM attributes to the rules engine. The processing device then receives. from the rules engine, an identification of one or more prioritized physical hosts of the plurality of physical hosts. The processing device provisions the VM on one of the one or more prioritized physical hosts.