Some Gotchas with Remote Administration of Hyper-V

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As I mentioned in my previous post, last month I built out a new virtual environment using Hyper-V on Server Core. Since you can't run MMC -- and therefore Hyper-V Manager -- on Server Core, you need to use remote administration to manage the VMs.

John Howard's blog series on Hyper-V Remote Management is by far the definitive source for getting Hyper-V up and running on Server Core. It provides an excellent step-by-step guide for enabling remote administration, opening various firewall ports, configuring DCOM permissions (if you don't want to use admin accounts), etc. If you haven't yet at least scanned John's posts, I highly recommend doing so before embarking on the Hyper-V on Server Core path.

There is one snag, however, that I want to point out with regards to John's scenarios.

The instructions in John’s blog posts work when:

  • both the Hyper-V server and the client are in WORKGROUP mode, or
  • when the client and server are members of the same domain or trusted domains, or
  • when the Hyper-V server is in WORKGROUP but the client is in a domain

[Note that I personally verified the second and third scenarios above while initially building out my Hyper-V server; I am trusting that the first scenario works based on John’s posts.]

However, if the client is a member of DOMAIN1 and the Hyper-V server is a member of DOMAIN2 – and there is no trust relationship between DOMAIN1 and DOMAIN2 – then Hyper-V Manager pukes with a message about not being able to connect to the RPC server. Also note that in this scenario Disk Management pukes as well with the infamous error message:

RPC server is unavailable

To picture this scenario, imagine you have a Hyper-V server joined to your internal domain, but now I come along and try to use Hyper-V Manager from my laptop which is joined to the internal Microsoft domain. It simply doesn't work -- and neither does Disk Management.

At this point, you might be thinking something like “Jeremy, it sounds like a firewall issue or you haven’t enabled Remote Volume Management.” However, immediately after receiving the "RPC server is unavailable" message on my laptop, I was able to connect the Disk Management console to the Hyper-V server just fine from a Windows Server 2003 member server in the same domain.

In my mind, that indicated the firewall and remote administration were configured correctly. After a little research, it appeared that I was hitting a known bug with WMI when the client and server are in different, untrusted domains.

To workaround this issue, I did two things.

First, I created a new Vista VM and joined it to my customer's internal domain. After installing the Hyper-V Remote Management Update for Windows Vista (KB952627), I was able to start, stop, and create VMs on the Hyper-V server. Excellent.

Second, since I didn't want to have to always fire up my Vista VM just to view or change the Hyper-V settings on the server, I installed the Hyper-V Update for Windows Server 2008 x64 Edition (KB950050) on one of the VMs running on the Hyper-V server. This obviously doesn't completely replace the need for a remote administration client due to the "Catch-22" scenario -- meaning, if the VM isn't running, you can't use Hyper-V Manager from the VM to start the VM ;-)

Someday soon, I'm hoping we will release a few command line tools for Hyper-V that allow you to perform some basic operations such as starting or stopping VMs. This would be great on Server Core -- and no, I don't want to install PowerShell in order to do this ;-)  [In keeping with the spirit of Server Core, I want to install as little as possible on the host.]

Lastly, I want to point out one of the stumbling blocks that I encountered along the way. Before I actually created the Vista VM that I mentioned earlier for remote administration, I initially created a Windows Server 2008 x86 VM and installed the 32-bit version of KB950050 in order to use Hyper-V Manager to remotely administer the Hyper-V server.

According to the corresponding KB article:

Update for Windows Server 2008 (KB950050)
This 32-bit update package includes the release version of the following:

  • The Hyper-V Manager console
  • The Virtual Machine Connection tool for x86-based editions of Windows Server 2008

Based on my experience installing the Hyper-V Remote Management Update for Windows Vista (KB952627) and the note above from the KB article, after installing KB950050 on Windows Server 2008 I expected to be able to start MMC and add the Hyper-V Manager snap-in. However, it doesn't quite work that way.

Fortunately, I received a quick response to my inquiry from Alex Kibkalo, a fellow Architect with Microsoft Consulting Services in Russia.

To enable Hyper-V Manager after installing KB950050, you need to enable the corresponding feature:

  1. Open Server Manager. (If Server Manager is not running, click Start, point to Administrative Tools, click Server Manager, and then, if prompted for permission to continue, click Continue.)
  2. In Server Manager, under Features Summary, click Add Features.
  3. In the Add Features Wizard, on the Select Features page, expand Remote Server Administration Tools, and then expand Remote Administration Tools
  4. Click Hyper-V Tools, and then proceed through the rest of the wizard.

For more information on deploying Hyper-V, refer to the Hyper-V Planning and Deployment Guide.