Query Hyper-V Virtual machines using Windows PowerShell

Being a lazy administrator as I am, I try to minimize the amount of mouse-clicks I need to make to retrieve information about something on a Windows platform. As I have been using Microsoft Hyper-V on a bunch of my test machines, I always check if a VM is up and running before I power down my host machine (imagine the amount of electricity consumed just by keeping your machine up and running even without using it). This is specifically the case when dealing with my Windows XP VMs. I noticed that the profiles get corrupted if I shutdown the host machine without properly shutting down the VM. So, I always made sure that the VMs are not running before powering down the host machine.

I wrote a PowerShell command to query the current state of the VMs running on Hyper-V


Get-WMIObject -class "MSVM_ComputerSystem"-namespace "root\virtualization"-computername "."

This will actually display a bunch of information about the VMs running on Hyper-V but what we're really concerned about is the name of the VM and it's currently running state. These two properties are associated with the ElementName and EnabledState attributes of the MSVM_ComputerSystem class. All we need to do with the command above is to pipe the results to a Select-Object cmdlet, specifying only these two properties, as follows

Get-WMIObject -class "MSVM_ComputerSystem"-namespace "root\virtualization"-computername "." Select-Object ElementName, EnabledState

While the EnabledState property will give you a bunch of numbers, I'm only concerned with those values equal to 2, which means that the VM is running. But, then, you might not remember what the value 2 means. So might as well write an entire script that checks for the value of the EnabledState property. I've used the GWMI alias to call the Get-WMIObject cmdlet

$VMs = gwmi -class "MSVM_ComputerSystem"-namespace "root\virtualization"-computername "."
foreach ($VM IN $VMs)
{
switch ($VM.EnabledState)
{
2{$state="Running" }
3{$state="Stopped" }
32768{$state="Paused" }
32769{$state="Suspended" }
32770 {$state="Starting" }
32771{$state="Taking Snapshot" }
32773{$state="Saving" }
32774{$state="Stopping" }
}
write-host $VM.ElementName `,` $state
}

On a side note, make sure you are running as Administrator when working with this script as you will only see the VMs that your currently logged in profile has permission to access. Running as Administrator will show you all of the VMs configured on your Hyper-V server

Enabling wireless on Windows Server 2008 - and eventually allowing Hyper-V guests to use it

A lot of you may probably ask why the need to enable wireless on a server operating system. Well, if you're like me who runs a server operating system on a laptop for testing purposes, there's a thousand and one reason why you would like to have it enabled. Now, since my Windows XP work-machine is now a virtual machine, I would need to have the wireless on my laptop enabled and working with Windows Server 2008. For this, you would need to install the Wireless LAN Service feature in Windows Server 2008. This article provides a detailed step-by-step procedure on enabling wireless on your Windows Server 2008. You just need to make sure that you have the appropriate Windows Server 2008 drivers for your wireless adapter or it won't work.

But my dilemma didn't stop there. I obviously don't want to access the internet via the Windows Server 2008 platform. That's what my Windows XP virtual machine is for. So what I did was to add an Internal virtual network using Hyper-V's Virtual Network Manager. This will create another network adapter on the host operating system - in this case, Windows Server 2008. I've renamed this WiFi-Guest-Bridge. Next, I've added a network adapter on the Hyper-V guest and mapped it to this virtual network. Once, I've done both of these, I've bridged the wireless network adapter and the WiFi-Guest-Bridge network adapter, thereby, providing wireless connectivity to my Hyper-V guest.

Keith Combs provided a step-by-step procedure (with screenshots) on how to configure wireless networking with Hyper-V guests in his blog

It is very important to name your network adapters accordingly as Windows does a real good job of using a generic naming convention (i.e. Local Area Network x) which adds confusion especially if you are dealing with a ton of virtual networks from within a single Hyper-V (or other virtualization) platform