An administrator is configuring a stretched DRS/HA clusters. The administrator wishes to restrict the failover of VMs to certain hosts within a given site. Which vSphere feature satisfies this requirement?
DRS Storage Groups
DRS Host Groups
Page 75 from vsphere-esxi-vcenter-server-50-resource-management-guide.pdf
DRS Host Group is a prerequisite of VM-Host Affinity rule. In DRS group you will create a list of available hosts from specific virtual machines.
Create a Host DRS Group
A VM-Host affinity rule establishes an affinity (or anti-affinity) relationship between a virtual machine DRS group with a host DRS group. You must create both of these groups before you can create a rule that links them.