A host controller selects a host from a host cluster to run a virtual machine. In one embodiment, a host controller receives a request to run a virtual machine. The virtual machine may be a newly added virtual machine, or an existing virtual machine that needs to migrate from a currently active host to another host. The host controller selects a host from the host cluster based on current central processing unit (CPU) consumption and expected load to be incurred by the virtual machine. The expected load may be estimated from the number of cores to be used by the virtual machine. The host controller then assigns the virtual machine to run on the host.