A fellow VCI who was teaching the vSphere 5 What's New training course got a question from a student asking what happens to resource pools when vCenter goes down, because with vSphere 5.0 all the setting for resource pools are "moved" to vCenter.
Andy Cary who works as a Senior Technical Trainer at VMware responded immediately with: I created a RP on my vCenter and turned off expandable reservations for memory. Placed VM1 under said resource pool and failed to power up because the VM need to reserve memory for the overhead of running the VM (had no reservations set on the RP). So next I directly connected to the host and powered on the VM with no problem at all. However when you go back to the vCenter it displays:
The Cluster with the RP is now invalid because it can see the VM has powered on. So the configuration about DRS RP is saved on the vCenter but it doesn't stop you going directly to the host an powering on the VM. Now in vSphere 5.0 if you directly connect to a host and try and create a local resource pool it will throw up an error saying this isn't allowed because it can see you are managed by vCenter, this is the case even if the Host isn't a member of DRS cluster.
So the creation and management of RP is done via vCenter, if vCenter goes down the rules cannot be applied so you could get admin powering on VMs by directly connecting to the hosts. So in summary all we have done is said "You can only create, modify resource pools via vCenter and not by directly connecting to the host"
Andy Cary who works as a Senior Technical Trainer at VMware responded immediately with: I created a RP on my vCenter and turned off expandable reservations for memory. Placed VM1 under said resource pool and failed to power up because the VM need to reserve memory for the overhead of running the VM (had no reservations set on the RP). So next I directly connected to the host and powered on the VM with no problem at all. However when you go back to the vCenter it displays:
The Cluster with the RP is now invalid because it can see the VM has powered on. So the configuration about DRS RP is saved on the vCenter but it doesn't stop you going directly to the host an powering on the VM. Now in vSphere 5.0 if you directly connect to a host and try and create a local resource pool it will throw up an error saying this isn't allowed because it can see you are managed by vCenter, this is the case even if the Host isn't a member of DRS cluster.
So the creation and management of RP is done via vCenter, if vCenter goes down the rules cannot be applied so you could get admin powering on VMs by directly connecting to the hosts. So in summary all we have done is said "You can only create, modify resource pools via vCenter and not by directly connecting to the host"
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