So you're running the new ESX 3.5 update 2. And you want to try the new EVC feature on your cluster. And you've found it under "edit settings" on your cluster object...
And then VirtualCenter refuses to enable it for you, because there is still at least one VM powered on in the cluster. Of course there is, because your VirtualCenter runs in a VM, in that same cluster. Catch-22 ?
Well, getting round this is a bit weird, but nevertheless possible. Here's what I did on my two-node test cluster:
Step one: you evacuate one ESX host in your cluster. You put it in maintenance mode, and move it out of the cluster, right under your datacenter object.
Two: manually migrate (VMotion via drag-and-drop for example) your VirtualCenter VM (running on a host in the cluster) to the host that is now outside the cluster. Do this with all other VMs that were still running in the cluster.
Three: enable EVC on your cluster. This now works, because the cluster doesn't contain any running VMs anymore.
Four: migrate the VMs back to a host within the cluster (again, drag and drop)
And finally: put the host back into the cluster.
And then VirtualCenter refuses to enable it for you, because there is still at least one VM powered on in the cluster. Of course there is, because your VirtualCenter runs in a VM, in that same cluster. Catch-22 ?
Well, getting round this is a bit weird, but nevertheless possible. Here's what I did on my two-node test cluster:
Step one: you evacuate one ESX host in your cluster. You put it in maintenance mode, and move it out of the cluster, right under your datacenter object.
Two: manually migrate (VMotion via drag-and-drop for example) your VirtualCenter VM (running on a host in the cluster) to the host that is now outside the cluster. Do this with all other VMs that were still running in the cluster.
Three: enable EVC on your cluster. This now works, because the cluster doesn't contain any running VMs anymore.
Four: migrate the VMs back to a host within the cluster (again, drag and drop)
And finally: put the host back into the cluster.
Comments
I tried your procedure for a customer here and it fails at step #4 when vmotion back to the EVC enabled cluster because of a mismatch detected for CPU feature SSE4.1.
Looks like there is no way to enable EVC w/o shutting down the VMs :(
I guess we will have a ong week-end soon here :)
Cheers,
Didier