I would like to ask when forming a vmware cluster, for say, 6 hosts, could the vms only would vmotion (High availabilty AND drs) in one or 2 specific hosts.
Usually not, but there can be two occassions where this happens:
- I've seen situations in a mixed ESXi 4.0 and ESXi 5.1 cluster where DRS would move all VMs to the 5.1 hosts untill the host had 98% memory load.
- When you start with (or move) all VMs on the two hosts and there are still enough resources on those two hosts, DRS doesn't have to move any VMs. But I would expect that each new VM would be moved to other hosts.
vMotion compatibility issues? Say you are using Distributed Switches, if you forgot to register all hosts to those switches (and then doublecheck uplinks).
if this is a vCloud Director cluster, ensure that the host is enabled and prepared to enable the vsla_fence module (vMotion requirement too).
If this has nothing to do with vCloud Director, then you might want to post in the appropraite forum.