Big problem going on right now within the web client.. and note, the problem I will describe does NOT occur in the thick client.. go figure.
DRS, when in either automatic mode, will power a VM up on the host it chooses, no way around it. OK, great.. but what about when you want to choose the host to power it up on??
DRS, when in manual mode, is supposed to allow you to decide what host to power the VM up on, but this doesn't work in the web client, only in the thick client. Here what's going on:
In this screenshot, DRS is in manual mode, and when powering on the VM I get this window, and note how there is only 1 host DRS is recommending even though there are 10 hosts in my cluster, and they all have plenty of resources to power on the VM. I have host names scribbled out, but trust me they are both different hosts, and what this means is that DRS even in manual mode wants to change the VM to a new host, a single host, without presenting other options. And when I uncheck the box next to the recommendation the OK button greys out so you can't power on the VM at all.
You might say "so what's the big deal?"
Well, upgrading the VM compatibility has been locking VMDKs, so when you go to power on the VM after compatibility upgrade, if it is moved to a different host, will fail to power on due to the lock.
Once the VMDKs are locked, you have to either follow the exhaustive KB to use vmksftools to unlock, or vmotion the VM back to the original host to get it to power on.
But wait - if you simply migrate the VM back to the host that has the lock on the VMDKs, DRS will once again try to move the VM to a new host when you once again go to power it on.. you get caught in a loop.
At this point your choices are to either use the KB to unlock the disks, which is a pain, or you can log into the host directly and power the VM from the host itself preventing vCenter from engaging DRS.
Does anyone have a workaround for this?
Does anyone know why DRS as shown above is only providing 1 host as a power on option instead of the entire list of hosts in the cluster?
We are in the process of upgrading a very large # of VMs, and this is something that is creating some major headaches.
And if you didn't believe me when I said this works fine in the thick client, here is your proof, the cluster I'm powering on the VM in, set to DRS manual, has 4 hosts!: