I tried that too, but if I set this constraint:
SCHED_DS_REQUIREMENTS = "NAME=\"tier1-images\""
I get this error:
Cannot dispatch VM: No system datastore meets capacity and SCHED_DS_REQUIREMENTS: ("CLUSTERS/ID" @> 100) & ( NAME="tier1-images" )
Which I think implies this can only allow me to se the system datastore - not the images datastore where the main image will be cloned (although this is not explicitly documented).
Am I missing something very obvious? Thanks!