Unable To Delete Hyper-V Root Snapshot in Hyper-V Manager

During a build-out for a customer it became necessary to move some virtual machines between a Hyper-V 2012 cluster and a Hyper-V 2012 R2 cluster but when trying to do so, all sorts of nasty errors came cropping up:

Live Migration Error Due To Differencing Disk

Error (12700)
VMM cannot complete the host operation on the host1.contoso.com server because of the error: Virtual machine migration operation for ‘MachineToMove.contoso.com’ failed at migration destination ‘host2.contoso.com’. (Virtual machine ID 1D5042AA-1A93-4635-9F0A-F7C7B0D10BDD)

Failed to access disk ‘C:\ClusterStorage\Volume2\MachineToMove.contoso.com\Windows Server 2012 DC with SP1_disk_1_3F40B5A6-E8DC-4752-873C-D9742C9419F4.avhdx’: ‘The system cannot find the file specified.'(‘0x80070002’).
Unknown error (0x800b)

Error (23753)
The virtual machine or tier load balancer configuration requires an IP pool and there are no appropriate IP pools accessible from the host.

Recommended Action
Select a host with access to an appropriate IP pool and try the operation again.

Live Migration Error Due To Differencing Disk 2

Error (12700)
VMM cannot complete the host operation on the MachineToMove.contoso.com server because of the error: Virtual machine migration operation for ‘MachineToMove.contoso.com’ failed at migration source ‘Host1’. (Virtual machine ID 1D5042AA-1A93-4635-9F0A-F7C7B0D10BDD)

Virtual machine migration for ‘MachineToMove.contoso.com’ failed because configuration data root cannot be changed for a clustered virtual machine. (Virtual machine ID 1D5042AA-1A93-4635-9F0A-F7C7B0D10BDD)
Unknown error (0x8005)

Recommended Action
Resolve the host issue and then try the operation again.

You may notice in the top error that the disk path is pointing to an odd file name. Looking at the settings for the machine in Hyper-V Manager and inspecting the disk, we find:

Live Machine Properties

Lo and behold, it’s a differencing disk. Let’s try removing the snapshot that created it:

Hyper-V Snapshot Missing Delete

And there’s the problem – no delete option!

Let’s look at the snapshot in PowerShell. To do so, open an elevated PowerShell session on a Machine with the Hyper-V PowerShell tools installed and run:

Get-VMSnapshot -VMName MachineToMove.contoso.com -ComputerName host1.contoso.com | fl

Here’s the output for the above VM:

SnapshotType : Recovery
VMId : 1d5042aa-1a93-4635-9f0a-f7c7b0d10bdd
VMName : MachineToMove.contoso.com
State : Off
Key : Microsoft.HyperV.PowerShell.SnapshotObjectKey
IsDeleted : False
ComputerName : host1.contoso.com
Id : 4382dc53-2fdd-476f-91b8-81963c292d24
Name : MachineToMove.contoso.com - Backup - (1/16/2014 - 6:00:19 PM)
Version :
Notes : #CLUSTER-INVARIANT#:{434c76e7-5581-463a-b1b4-71027d39770f}
Generation :
Path : C:\ClusterStorage\Volume2\MachineToMove.contoso.com
CreationTime : 16/01/2014 20:22:24
IsClustered : True
SizeOfSystemFiles : 49254
ParentSnapshotId :
ParentSnapshotName :
MemoryStartup : 8589934592
DynamicMemoryEnabled : False
MemoryMinimum : 536870912
MemoryMaximum : 1099511627776
ProcessorCount : 4
RemoteFxAdapter :
NetworkAdapters : {MachineToMove.contoso.com}
FibreChannelHostBusAdapters : {}
ComPort1 : Microsoft.HyperV.PowerShell.VMComPort
ComPort2 : Microsoft.HyperV.PowerShell.VMComPort
FloppyDrive : Microsoft.HyperV.PowerShell.VMFloppyDiskDrive
DVDDrives : {DVD Drive on IDE controller number 1 at location 0}
HardDrives : {Hard Drive on IDE controller number 0 at location 0, Hard Drive on SCSI controller
number 0 at location 0}
VMIntegrationService : {Time Synchronization, Heartbeat, Key-Value Pair Exchange, Shutdown...}

Time to remove it:

Get-VMSnapshot -VMName MachineToMove.contoso.com -ComputerName host1.contoso.com | Remove-VMSnapshot

You can run this command while the machine is running and if you look in Hyper-V after running this you’ll see that the differencing disk will quickly merge into the parent and then the recovery-point snapshot will be removed. Migrating the VM in this state should go without a hitch.

What caused this?

In this instance, the environment is running HP Data Protector 8.0 which is HP’s incredibly powerful (albeit rather old-looking) backup platform. The environment had been configured to back up the machines in the Hyper-V cluster using the HP StoreVirtual P4000 VSS/VDS Providers along with Application Aware Snapshot Manager. As I understand it, this uses the differencing disks so that incremental backups can be achieved – they’re merged and renewed during each Full backup. This is why you see the word “Backup” in the snapshot name along with the data and time that Data Protector took the backup.

Hyper-V 2012 -> 2012 R2 Cluster Migration Issues

Quick post more to document an oddity than anything…

Migrating machines from a 2012 cluster to a 2012 R2 cluster using VMM 2012 R2 with mixed results. In particular, I’m seeing the machines duplicated in Failover Cluster Manager – one of the two seems to be the live machine and the second, prefixed with SCVMM (as all VMM created machines are) seems to be broken with various errors such as ID 21502 “Missing or invalid virtual machine ID resource property”. Simply removing the duplicate starting with SCVMM and all seems to be ok.

Odd though.

SCVMM 2012 R2 Bare Metal Deploy WinRM Error

I’ve been getting to know SCVMM much better, in particular the ability to provision new hosts using the iLO port on a fresh HP server and I found this problem that the search engines don’t seem to have an answer for.

Towards the end of the deploy process, after the OS is installed, joined to the domain and the agent is installed, it stops with this error:

VMM Bare Metal Deploy Error

Error (20552)
VMM does not have appropriate permissions to access the resource C:\Windows\system32\qmgr.dll on the server.domain.com server.

Recommended Action
Ensure that Virtual Machine Manager has the appropriate rights to perform this action.

Also, verify that CredSSP authentication is currently enabled on the service configuration of the target computer server.domain.com. To enable the CredSSP on the service configuration of the target computer, run the following command from an elevated command line: winrm set winrm/config/service/auth @{CredSSP=”true”}

As a result the network connections and a few other bits don’t correctly apply but the host does appear in VMM.

Looking at the host properties, you can see it’s a WinRM issue:

VMM Bare Metal Deploy Error 2

Error (20506)
Virtual Machine Manager cannot complete the Windows Remote Management (WinRM) request on the computer server.domain.com.

Recommended Action
Ensure that the Windows Remote Management (WinRM) service and the Virtual Machine Manager Agent service are installed and running. If a firewall is enabled on the computer, ensure that the following firewall exceptions have been added: a) Port exceptions for HTTP/HTTPS; b) A program exception for scvmmagent.

Having checked all of the obvious, including that WinRM is enabled as it should be, GPOs aren’t getting in the way and firewall rules are set up to allow the traffic, I took a look at the security log on the new host:

VMM Bare Metal Deploy Error 3

In the Microsoft Documentation, it says very specifically that when creating a Host Profile for the deployment, the Run As account that you use to join the host to the domain should have “very limited privileges” and “should be used only to join computers to the domain”. Hence the dedicated Domain Join account I used.

So why is this account logging into the server after deployment? A quick trip to the host properties reveals the answer:

VMM Bare Metal Deploy Host Properties

D’oh! Nicely done SCVMM.

Go back into the Host Profile:

VMM Bare Metal Deploy Host Profile

And there is our Domain Join account. Create a new Run As account with the appropriate permissions to administer newly created hosts (unfortunately this is possibly Domain Admins, depending on your environment), update the Host Profile and redeploy the host and you should be good. Please note that you cannot use the SCVMM service account for this task, it has to be separate account.

System Center 2012 Dynamic Optimization Explained

Hilton Lange over at the offical SCVMM Blog has posted a fantastic write-up of the mechanics of Dynamic Optimization.

Of particular interest to me is the logic used to determine whether or not to rebalance a cluster. I’ve seen clusters before where Network Optimizations have been enabled and DO does not balance any VMs at all however live migrations work. This is caused by warnings generated during the evaluation process as a result of Network Optimization not being supported on the hardware and as you can see from the above link, any warnings means a host is discounted. Unfortunately there isn’t much information in SCVMM itself about the results of the logic when DO runs; vSphere is a bit better in that regard.