Quick and Dirty Reset of a Hyper-V VM with PowerShell

Note: Remember, this is a “Quick and Dirty” solution. In fact, because credentials are hard‐coded in the script, it is “Quick and Filthy”. But that tends to be the nature of IT‐Pro quick fixes, and I found it useful for a particular scenario. Just remember, this is merely being shown as an example and not a best practice.

Background: I had a problematic VM that would freeze over a period of time which required a “Hard Reset” to make it functional again. I wanted a way to reset the VM remotely, rather than from the console of the Hyper‐V parent.

The following steps will be taken to perform a hard reset on a VM:

  1. List ﴾enumerate﴿ the virtual machines on a Hyper‐V parent and identify the VM to reset by capturing its “Name” ﴾GUID﴿.
  2. Build a credential object that allows the execution of the RequestStateChange method ﴾typically Administrator credentials are required﴿.
  3. Execute the RequestStateChange method

List ﴾Enumerate﴿ the virtual machines on a Hyper‐V parent

PS> winrm enumerate wmi/root/virtualization/msvm_computersystem /r:<Hyper-V Parent> /u:<username> /p:<password>
     Msvm_ComputerSystem
     AssignedNumaNodeList = 0
     Caption = Virtual Machine
     CreationClassName = Msvm_ComputerSystem
     Description = Microsoft Virtual Machine
     ElementName = WSMANR2
     EnabledDefault = 2
     EnabledState = 2
     HealthState = 5
     InstallDate
     Datetime = 20110725T20:31:41Z
     Name = C4E916BB92D54A4097C10664FCC0123B
     NameFormat = null
     OnTimeInMilliseconds = 5774786
     OperationalStatus = 2
     OtherEnabledState = null
     PrimaryOwnerContact = null
     PrimaryOwnerName = null
     ProcessID = 2064
     RequestedState = 12
     ResetCapability = 1
     Status = null
     StatusDescriptions = Operating normally
     TimeOfLastConfigurationChange
          Datetime = 20110822T17:33:46.726979Z
     TimeOfLastStateChange
          Datetime = 20110822T17:33:46Z

Build a credential object ﴾this approach allows for the credentials to be hardcoded into a script, whereas the typical “get‐credential” cmdlet will not allow the password to be stored in the script and enforces the more secure method of manual entry of the password﴿.

PS> $password = convertto-securestring -String "<password>" -asplaintext -force
PS> $credential = new-object -typename System.Management.Automation.PSCredential -argumentlist "<username>",$password

Execute the RequestStateChange method on the VM ﴾acts like a Hard Reset for this example﴿

PS> # Various supported state changes: 2=Turns the VM on, 3=Turns the VM off, 10=A hard reset of the VM, 32768=Pauses the VM, 32769=Saves the state of the VM
PS> invoke-wsmanaction -action RequestStateChange -resourceuri wmi/root/virtualization/msvm_computersystem valueset @{RequestedState="10"} –selectorset @{Name="<VM Name/GUID from Above>"} -computername <HyperV Parent> -authentication default -credential $credential

Enjoy!

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