@olivierlambert In my understanding, Anti affinity tags only looks for the tags that are attached to the VM.
For example:
Datacenter 1
Host 1
VM1-1
Host 2
VM1-2
Datacenter 2
Host 3
VM2-1
Host 4
VM2-2
VM1-1 and VM1-2 should be able to migrate to Host 1 and Host 2.
VM2-1 and VM2-2 should be able to migrate to Host 3 and Host 4.
But VM1-1 and VM1-2 should never be able to migrate to Host 3 and Host 4.
VM2-1 and VM2-2 should never be able to migrate to Host 1 and Host 2.
With the current (Anti) Affinity tags, it will only look to the tags attached to the VM, so in the example it would be possible for VM1-1 to go to Host 4, if VM2-2 would be at Host 3 together with VM2-1.
But if we could tag the hosts, it would not be possible for VM1-1 and VM1-2 to be on Host 3 and Host 4