You can configure vSphere HA to designate specific hosts as the failover hosts.
With dedicated failover hosts admission control, when a host fails, vSphere HA attempts to restart its virtual machines on any of the specified failover hosts. If restarting the virtual machines is not possible, for example the failover hosts have failed or have insufficient resources, then vSphere HA attempts to restart those virtual machines on other hosts in the cluster.
To ensure that spare capacity is available on a failover host, you are prevented from powering on virtual machines or using vMotion to migrate virtual machines to a failover host. Also, DRS does not use a failover host for load balancing.
If you use dedicated failover hosts admission control and designate multiple failover hosts, DRS does not attempt to enforce VM-VM affinity rules for virtual machines that are running on failover hosts.