How to configure Hyper-V to use a wireless connection in Windows 8.1

I haven’t used Hyper-V for a while but when I recently built a Windows 8.1 test bed VM I needed a virtualisation platform  and Hyper-V was more or less ready to go within my Windows 8.1 host laptop.

The only hiccup I encountered along the way—and one I was familiar with from my days running Windows Server 2008 on my laptop simply so I could run Hyper-V—was configuring Hyper-V to make use of my laptop’s wireless connection. This time I followed Rick Gipson’s excellent post to get everything working  and I summarise/condense his steps here in the interest of preservation and to document a few notes relevant to my Win 8.1 environment. Check out Rick’s post for screenshots.

1. Create a new Internal virtual network switch named Virtual WLAN from the Virtual Switch Manager in Hyper-V Manager. A new Unidentified Network connected to vEthernet (External WLAN) will now be visible within the host OS’ Network and Sharing Center. Note I renamed this connection to vEthernet (External WiFi) in Windows to reinforce its relationship to the wireless adapter and differentiated it from the Hyper-V object.
2. In Hyper-V Manager, configure the target VM’s network adapter to use the newly-created virtual switch (i.e. Virtual WLAN). Note Rick suggested the need to add a new Legacy Network Adapter but I found this was unnecessary.
3. In the host OS’ Network and Sharing Center, share the host’s physical WiFi adapter by checking the Allow other network users to connect through this computer’s internet connection box and specifying the Home networking connection as vEthernet (External WiFi). Note Rick’s screenshots show the Home networking connection field as a drop-down list but my current configuration displays as a text field. The WiFi adapter should now be listed as Shared in the host OS’ adapter settings.
4. Start up your guest VM when you’re connected to a wireless and enjoy network connectivity including internet access.

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Must Have Windows Server 2008 R2 Hyper-V Hotfixes

Now there's a damning blog post title!

In brief, I've had a few issues since installing Windows Server 2008 R2 and adding the Hyper-V Role on my Dell Precision M6500 Core i7 laptop (if you've landed on this post and you don't care about laptops--i.e. you're an admin--don't stop reading now as this post will likely apply to you too). This post is meant to be a running log of problems and their resolutions while we await the next service pack, I suppose.

Problem #1: Blue Screen of Death/random reboots

Resolution:

• Install the http://support.microsoft.com/kb/975530 hotfix on your Hyper-V hosts or use the work around detailed in the KB article.

KB975530: Stop error message on a Windows Server 2008 R2-based computer that has the Hyper-V role installed and that uses one or more Intel CPUs that are code-named Nehalem: "0x00000101 - CLOCK_WATCHDOG_TIMEOUT"

Symptoms, event log entries, and whatnot: Unexpected freezes, BSODs and reboots during periods of high network activity.

• Event ID 219, The driver \Driver\WUDFRd failed to load for the device USB\VID_0A5C&PID_5800&MI_01\7&66de6c9&0&0001.
• Event ID 41, The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
• Event ID 4, Broadcom NetXtreme 57xx Gigabit Controller: The network link is down.  Check to make sure the network cable is properly connected.
• Event ID 1001, The computer has rebooted from a bugcheck.  The bugcheck was: 0x00000101 (0x0000000000000019, 0x0000000000000000, 0xfffff880020ce180, 0x0000000000000003). A dump was saved in: C:\Windows\MEMORY.DMP. Report Id: 043010-31168-01.
  

Apparently this issue is caused by an Intel erratum affecting Nehalem-based processors (i.e. Xeon 5500, Core i7-800, and Core i5-700 series).

Problem #2: Guest VMs freeze, lost connection

Resolution:

• Install the http://support.microsoft.com/kb/974909 hotfix
• Install the http://support.microsoft.com/kb/981836 hotfix (this KB is specific about Windows Server 2003 but a Microsoft representative suggested it's applicable to all VMs as the hotfix updates the integration services components generally)
• Update integration services on all guest VMs

None of this worked for me but changing my host power settings from Balanced to High performance did. In theory you should be able to revert to Balanced after installing and the above.

You may also want to investigate turning off TCP offloading.

Symptoms, event log entries, and whatnot: Hyper-V console freezes in some virtual machines but not others (the only one affected in my case was an XP VM upgraded from Virtual PC 2007 SP1), Hyper-V manager reports the Heartbeat as "Lost connection".

• Event ID 5: The miniport 'Microsoft Virtual Machine Bus Network Adapter #3' hung.

...followed by...

• Event ID 4: The miniport 'Microsoft Virtual Machine Bus Network Adapter #3' reset.

For additional information about this problem, definitely check out http://social.technet.microsoft.com/Forums/en-US/windowsserver2008r2virtualization/thread/0408a28d-6ab8-4c85-8773-4bc42c2df40b

More to come? Hopefully not! ;-)

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How to merge Hyper-V snapshots to a parent .vhd

Jason Neurohr has a detailed, illustrated post on the subject of merging Hyper-V snapshots to a parent .vhd, leaving you with a single .vhd file you can run without having to worry about the snapshots. I found Jason’s post excellent and the steps described worked like a charm the first time I had to do this (while I didn’t persist, I found exporting a VM with snapshots from the Hyper-V R2 console just wasn’t working—the snapshots weren’t exported as expected).

The merge process is actually quite simple and I’m therefore reproducing just the relevant details from Jason’s post for my own future benefit:

• Backup the parent .vhd and all snapshot disks (.avhd)
• Change the extension for all snapshot differencing disks from .avhd to vhd
• Within the Hyper-V MMC, select the Edit Disk… option
• On the Locate Disk screen, locate the snapshot disk to be merged
• Select the Merge option and then the To the parent virtual hard disk option
• Finish the wizard and create a new virtual machine using the merged disk

If multiple snapshots exist, merge the most recent snapshot into the parent disk and work in reverse snapshot date order all the way back to the parent.

Can’t start Hyper-V VM after Windows Server 2008 R2 upgrade

Oh the tedium… Having used Windows Server 2008 R2 for a while, I was keen to upgrade the Hyper-V host environment supporting my dev infrastructure from RTM to R2. R2 seems faster and more refined; I was also wanting to play with the latest version of the System Center Virtual Machine Manager—which requires R2.

The upgrade process went smoothly once I figured out the installer would eventually present me with the upgrade option after telling it to install the Windows Server 2008 R2 Standard (Full Installation) option; this was briefly confusing to me  since I didn’t want to do a full installation! I shut down all my VMs properly beforehand and everything seemed pretty much good (I did have to recreate the one VM I normally auto-start but luckily I was able to reuse the .vhd itself and the machine came back to life with little hassle).

Today, however, I went to create a new VM but was unable to start it post-creation. Clicking start popped up a message telling me the VM could not initialize and Hyper-V could not create or access saved state file. The physical location of my VMs hadn’t changed but I read this error message as a permissions issue—but where to start?! The only thing I had to go on was that I was creating the new VM on another volume.

Fortunately Jevgenij Martynenko saved the day for myself and others in this forum post with the old trick of granting access to the root of the drive. I remember having to do this for ASP.NET back in the day for some reason…

Anyway, as per the instructions, I granted ‘Authenticated Users’ ‘List folder / read data’ permission to the root of my E:\ drive, setting the scope drop down to This folder only. I did not replace all child object permissions as apparently that causes more problems.

Starting the new VM was successful after this change.