In the PowerCLI world there is a kind of evil oneliner to remove all VM´s from a datacenter, I was searching for something alike in the Hyper-V v3 world

The PowerCLI command is

Get-VM | %{Stop-VM $_ -Confirm:$false; Remove-VM $_ -DeletePermanently -Confirm:$false

And of course that is pure evil because the parameter -deletepermanently will remove not only the VM but also it´s files from the datastore, The % is to take care of each VM and in case the VM is running I will shut it down (otherwise if I only run like Get-VM | Stop-VM -Confirm:$false | Remove-VM -deletePermanently -Confirm:$false I will only remove the ones running, cause I will get an error on the others because I cannot change state to what it is already)

In Hyper-V and the powershell v3 It is not quite as easy but of course it can be done and don´t you dare use the gui 😉

This approach requires that you have put your VM in a separate folder for each of them (or of course it will be clean in your default Hyper-V VM folder..)

The Remove-VM cmdlet does not allow you to actually remove the VM´s virtual hard disk and the folders (which in some times can become a bit messy after a while)

Here is my VM´s

And here is my folder

So if I remove one VM now with the Remove-VM TestVM1, this also requires that the VM is off.

And lets see in the folders what do we have

So to clean both VM´s and folder data I run all at once and this looks like this

Get-VM testvm* | %{ Stop-VM -VM $_ -Force; Remove-VM -vm $_ -Force ; Remove-Item -Path $_.Path -Recurse -Force}

And see in my VM´s folder how tidy and neat it is 😛

And as I started to describe in the top .. If you just use Get-VM | …  you will clean your Hyper-V host quick 🙂

Now that the Windows 2012 RC has arrived with the Powershell v3 I wanted to explore the functionality a bit more, I have seen some posts about how to use the Workflows but none when deploying VM´s in Hyper-V.

I have loaned some code from Mikael Nyström (Deployment Bunny) but had to rewrite a little to make it work with the workflow -parallel.

Also when I downloaded Mikael´s scripts they where automatically  blocked ( I had set my demo system to -Unrestricted) but as you see in the screenshot they are still blocked. but luckily I can use the Unblock-File cmdlet in the Powershell v3, when using the v2 there was a utility tool streams.exe from SysInternals that could help.

and here is it in the properties dialog

But if I have like 5-10 or 100 files I would like to use Powershell (Anyone out there unblocking like 100 scriptfiles by clicking in a dialog?)

To create the “Master” vhdx I used the Convert-WindowsImage.ps1 script, I am creating the master to be deployed with win 2012 RC datacenter core version (Updated:I got a tip in the comments to look at the Convert-WindowsImage instead of the Wim2VHD.ps1)

Now to my workflow, I am testing to create 5 VM´s at the same time with differential disks connected to the master. the workflows also set all VM´s to dynamic memory and starts them.

# Inparallel.ps1
#
# Niklas Akerlund
# 2012-06-03

workflow create-VMs
{
    $VMRefDisk = "C:\VMs\master.vhdx"
    $VMNetwork = "Intern"
    $VMBaseLocation = "C:\VMs"
    $VMMemory = 384MB
    foreach -parallel ($item in 1..5) {
          
        $VMName = "TestVM$item"    
        $VMLocation = New-Item -Path "$VMBaseLocation\$VMName" -ItemType Directory -Force
        $VMDiskLocation = New-Item -Path "$VMLocation\Virtual Hard Disks" -ItemType Directory -Force
        $VMDisk01 = New-VHD –Path $VMDiskLocation\$VMName-OSDisk.vhdx -Differencing –ParentPath $VMRefDisk 
  
        New-VM –Name $VMname –MemoryStartupBytes $VMMemory –VHDPath $VMDisk01.path -SwitchName $VMNetwork -Path $VMBaseLocation
   
        Set-VM -VMName $VMName -DynamicMemory

        Start-VM -VMName $VMName
    }
    Get-VM TestVM*
}

It is quite simple but still powerfull, If I for example had like more hosts i can deploy many VM´s at the same time and the thing that would stop me is the hardware and the storage 😛

I read this post by Ben (Virtual PC Guy) Armstrong about shrinking a virtual hard disk and thought this should be done with powershell.

So first I have to shrink the partition inside the VM, for this I use the New-CIMSession (instead of powershell remoting and such) and then I shut down the VM and shrink the VHDx file, As someone correctly noted, this shrink of the virtual disk file is only possible when using the new VHDx format.

The VM is part of the same domain as the hyper-V server from which I am running the script, this made it easier to make a cim connection. The VM is also a Win 8 beta cause I need the latest win framework with powershell 3.

As you can see, the disk in my VM is 60 GB and I want to shrink it to the minimum size * 20% (so i get at least some space left 😉

Now I will run my little script and here is what that looks like

# vNiklas Masterblaster shrink
#
# Niklas Akerlund / 2012-05-13

$VM = "Shrink8"

$cim = New-CimSession $VM

$partitionC = Get-Partition -CimSession $cim -DriveLetter C

$newSize = ($partitionC | Get-PartitionSupportedSize).SizeMin*1.20

Resize-Partition -PartitionNumber $partitionC.PartitionNumber -DiskNumber $partitionC.DiskNumber -Size $newSize -CimSession $cim

Get-Volume C -CimSession $cim

$VM = Get-VM $VM

Stop-VM $VM

$hdd = $VM | Get-VMHardDiskDrive

Resize-VHD -Path $hdd.Path -ToMinimumSize

Start-VM $VM

And here you can see the result, a quite simple solution..

Good luck in your shrinking 🙂

Update:  I totally missed that Ben had done a post about doing it with powershell, just after his other post when i was making this post… At least my solution show how to connect to a VM with CIM 🙂