To control the placement of virtual machines on hosts in a cluster, you can use DRS affinity rules or anti-affinity rules. There are two types of affinity rules:
VM-VM affinity rules: These rules specify affinity or anti-affinity between virtual machines. An affinity rule specifies that DRS should or must keep a group of virtual machines together on the same host. A use case of the affinity rules can be performance, because virtual machines on the same hosts have the fastest network connection possible. An anti-affinity rule specifies that DRS should or must keep a group of virtual machines on separate hosts. This prevents you from losing all of the virtual machines in the group if a host crashes.
VM-Host affinity rules: These rules specify affinity or anti-affinity between a group of virtual machines and a group of hosts. An affinity rule specifies that the group of virtual machines should or must run on the group of hosts. An anti-affinity rule specifies that the group of...