Affinity rules are settings that establish a relationship between two or more VMware virtual machines (VMs) and hosts.
VMware DRS (Distributed Resource Scheduler) is a utility that balances computing workloads with available resources in a virtualized environment. The utility is part of a virtualization suite called VMware Infrastructure 3.
A VMware resource pool is the aggregated physical compute hardware -- CPU and memory, as well as other components -- allocated to virtual machines (VMs) in a VMware virtual infrastructure.
A VMware vApp is a collection of virtual machines (VMs) and sometimes other vApps that host a multi-tier application, its policies and service levels.