[ovirt-users] Why and when does oVirt make a compute host part of the HCI Gluster?

My understanding is that in a HCI environment, the storage nodes should be rather static, but that the pure compute nodes, can be much more dynamic or opportunistic: actually those should/could even be switched off and restarted as part of oVirt's resource optimization. The 'pure compute' nodes fall into two major categories, a) those who can run the management engine, b) those who can't. What I don't quite understand is why both types seem to be made 'gluster peers', when they don't contribute storage bricks: shouldn't they just be able to mount Gluster volumes? The reason for my concern is that I actually want to manage these computing hosts with much more freedom. I may have them join and take on workloads, or not and I may want to shut them down. To my irritation I sometimes even see these 'missing' hosts being considered for quorum decisions or being listed e.g. when I do a 'gluster volume engine status'. I find hosts there, that definitely are not contributing bricks to 'engine' (or any other volume). Then I'm not even sure I have consistent behavior when I remove hosts from oVirt: I'd swear that quite a few remain as Gluster peers, even if they are completely invisible from the oVirt GUI (while hosted-engine --vm-status will still list them). So what's the theory here and would it be a bug if removed hosts remain gluster members?