Question:

In a Hypervisor High availability environment with Multiple hosts, is it possible to create VMs using MCS specifically on selected hosts?

Answer:

1. As per the product architecture, the XenDesktop DDCs have only visibility to the Hypervisor address which is specified in Host connection in XenDesktop studio 
2. Be it XenServer or be it VMWare or whichever hypervisor, XenDesktop just communicates with the Hypervisor host/cluster address specified, with the credentials specified in host connection.
3. Machine creation requests and Power management commands will be sent to the Host connection address and will wait for the status messages,  results whether it is success or failure. The results can be seen in DDC event logs and Studio.

For example , there is Hypervisor connection to the Vcenter server specified in hosting connection, and the High Availability architecture is at the back end with multiple ESX hosts which XenDesktop has no visibility. Once the Machine creation/removal requests or Power management commands given, the same is then received by the Vcenter server and those are done in the background in ESX hosts. Those activities, we cannot manage from XenDesktop. Hence any failover, fail back or load balancing activities done in between/among the ESX hosts in this scenario cannot be seen or managed by/from XenDesktop.