Choosing a Management OS for Hyper-V: Hyper-V Server

For the server edition of Hyper-V, you have a choice in management operating systems. You can use the free, no-GUI Hyper-V Server or you can use the full-fledged Windows Server. This will be the first of two articles in which I will argue both sides of the debate. In this installment, I’ll take the position that you should use Hyper-V Server.

A Clear Explanation of What Hyper-V Server Is

There’s a lot of confusion around all the various terms for Microsoft’s hypervisor. Microsoft takes no small part of the blame for that, as they use overlapping product names and terms. Some of it is just a natural consequence of the delivery methods. Some of the blame lies with the community, though, as many writers don’t do a great job using non-arbitrary product descriptors. I always cringe when I read an otherwise great article that refers to “Hyper-V Core”. There have been more than a few that I’ve wanted to link to, but I’ve chosen not to as I don’t want to contribute to the confusion.

So, we’re going to start this post off with a chart that clearly indicates what is what:

Term Meaning
Hyper-V “Hyper-V” is Microsoft’s hypervisor technology. There is no way to get Hyper-V all by itself. You must choose one of three possible delivery methods. When using the term “Hyper-V”, you are referring specifically to the hypervisor.
Hyper-V Server “Hyper-V Server” is a standalone product available as a direct download from Microsoft. Despite the awkward placement of the download, it is not an evaluation product download. This is one of the three delivery methods for Hyper-V. It is based on Windows Server, but has almost no roles or features except those that would be useful in a hypervisor management operating system.
Core “Core” is a mode for Windows Server that does not activate any of Explorer’s GUI components. It has no special relevance to Hyper-V as just about every Windows Server component and most non-WPF and non-Explorer-based applications can run on it.
Windows Server with Hyper-V In the 2008 product series, this was actually one way you could buy Windows Server. Naturally, there was also a SKU that didn’t have Hyper-V. Nowadays, this phrase is just used to indicate that the management operating system is Windows Server and that it has the Hyper-V role enabled. This is another of the three delivery methods for Hyper-V.
Client Hyper-V This is the trimmed-down edition of Hyper-V that ships with the desktop editions of Windows. These desktop editions represent the third delivery method for Hyper-V.
Hyper-V Core This term is nonsense. Please stop using it. It leads to a great deal of confusion in which we have people asking things like, “How do I install the full GUI on Hyper-V Core?” and people who are trying to help wasting a bunch of cycles trying to figure out what product is actually being used.It would help if Microsoft would stop using “HYPERSERVERCORE” and things like that in the text strings related to Hyper-V Server. <wink wink nudge nudge>

 

Reasons to Use Hyper-V Server as the Management Operating System

So, now that we’ve hopefully arrived at an understanding that this post is about the free product, let’s move on to the reason that you should use it as your management operating system choice.

  • It’s free! Who doesn’t like free? I know that there’s a huge push out there among some people to split hairs over the definition of “free”, but most of the English-speaking world takes the default position that when the adjective “free” is applied to a non-living corporate product, that means “doesn’t cost me anything”. That’s probably why Pepsi Free was fairly short-lived as a product name. Hyper-V is free in the default usage. Go download it and use it and (unless you find a way around the license agreement) you’ll never have to give a penny for it. This is especially useful for permanent test labs, now that Microsoft has killed TechNet subscriptions.
  • It’s lean. Hyper-V Server has a very small disk footprint compared to the other delivery methods. Much of a Windows distribution is there “just in case”. All those extra bits are why, with the exception of a few things, such as .Net Framework 3.x, you can enable just about every Windows role or feature without digging out the media. I’ve read at least one source that claims that Windows Server in Core mode is just as small as Hyper-V Server, but this isn’t true. Server Core is smaller than the full Windows Server if the binaries and resources for the GUI have never been added, but it is always larger than Hyper-V Server.
  • It’s more secure and stable. There’s less to attack and fewer things available to go wrong, so it will survive assaults and bugs that would take a full Windows Server down. A great many exploits target the Explorer binaries; Hyper-V Server can’t even install those binaries, so Hyper-V administrators can shrug off a lot of the security bulletins that keep the other admins up at night.
  • It doesn’t need as much patching. Patching is a real pain. You have to schedule it, you might need to notify your users of potential downtime, and you have to worry about whether or not Microsoft performed sufficient testing before releasing them. Well, with less content in the management operating system, Hyper-V doesn’t need nearly as many of them. As a bonus side effect, it’s less likely to need to be rebooted.
  • You never have to worry about activation. A lot of experts advise against using any form of antimalware in the management operating system. Since I’ve been able to use it on mine without any trouble, I personally make no recommendations either way. If you’re going to skip this software, then you need to be extra careful to keep Hyper-V hosts locked away from anything that might harm them. One common way to do that is with network isolation; it’s not really necessary for the management operating system to ever communicate with the Internet or even other internal hosts, so you can completely wall it off if you like. Unless it’s Windows Server. Then, it’s going to really want to talk to a licensing server periodically. Sure, there are ways around that. The best of them is to use Hyper-V Server instead.
  • It’s cheaper if you only want to virtualize desktop and/or Linux operating systems. Windows Server gives you some guest virtualization privileges, but they only apply to Windows Server operating systems. You can install Hyper-V Server and set up a highly-available VDI farm and only need to buy the desktop licenses. If even one of those desktops is running the same operating system generation as your hosts, you can install RSAT in it and completely manage your Hyper-V Server cluster from it without ever buying a single Windows Server license.
  • Upgrades are free! So, you didn’t spring for Software Assurance and here comes the new release of Windows and Hyper-V. What to do? Well, if you’re on Hyper-V Server, you can just upgrade to the next version of Hyper-V Server whenever it suits your schedule. No need for licensing negotiations or true-ups or anything else.

Responding to the Reasons Against Using Hyper-V Server

There are reasons not to use Hyper-V Server. Some of them of them aren’t that good, and some make no sense at all. We’ll start with those that are most valid and work our way down.

  • There’s no GUI available. Your only choices for working at the console of Hyper-V Server are the command line and PowerShell. That’s daunting for a lot of Windows administrators, to be sure. But, you can’t really avoid PowerShell unless you are completely satisfied with the basics. PowerShell is required for a number of advanced features and even some intermediate ones. Even if it’s not simple, it’s not as difficult as many people make it out to be. I, and many others, constantly write guides and books to make the processes as clear as possible. You can use things like Desired State Configuration to get the system set up quickly and easily. From there, you shouldn’t be using the console directly anyway. All the GUI tools will connect remotely. PowerShell will connect remotely. This is something you can do.
  • You can do more with Windows Server than you can with Hyper-V. From a technical standpoint, this is absolutely true. Windows Server has a stack of features that Hyper-V Server does not; just running Get-WindowsFeature on both will show you that. The problem is, it’s not supported to run very many of those roles and features with Hyper-V. Some of them will cause problems. All of them will steal resources from your guests, provided that the guests don’t steal resources from them first. Worse, if you install any role or feature that even has the capability to provide services to any external user or computer, you forfeit one of your Windows Server guest virtualization privileges. It’s much better to place those roles inside guest virtual machines. Then, it won’t matter what your management operating system is, because the guests are doing all the work.
  • Using Windows Server makes better use of the licenses you paid for. This is a myth I see used a lot: that the choice between Windows Server and Hyper-V Server is related to licensing. There is one, and exactly one, situation in which this is almost true. Automatic Virtual Machine Activation is a feature that requires you to install the Datacenter edition of Windows Server 2012 R2. But, it doesn’t quite make the myth truth because it only works for Windows Server 2012 R2 guests and even if you don’t install Datacenter, all that you forfeit is the AVMA feature; you still get all of Datacenter’s guest privileges. So, we need to continue repeating that it is a myth that using Windows Server as the management operating system grants any particular license benefits over using Hyper-V Server. If you run even one Windows Server guest, then the host needs a corresponding license. This is always true, and it does not matter one bit what operating system you choose to run as the management operating system. One Windows Server 2012 R2 Standard guest requires one Windows Server 2012 R2 Standard license for the host whether you are running Hyper-V Server or Windows Server in the management operating system. Five Windows Server 2012 R2 Standard guests require three Windows Server 2012 R2 Standard licenses for the host whether you are running Hyper-V Server or Windows Server in the management operating system. Thirty-six Windows Server 2012 R2 Standard guests require eighteen Windows Server 2012 R2 Standard licenses or one Windows Server 2012 R2 Datacenter license for the host whether you are running Hyper-V Server or Windows Server in the management operating system. If you have questions about this, you can start with our previous article on the subject. As always, I recommend that you contact Microsoft directly or speak with a credentialed licensing expert at an authorized reseller. They’ll tell you: licensing for your guests has no impact on and is not impacted by your choice of management operating system.

Summary

So, there’s my case for using Hyper-V Server as the management operating system.

Stay tuned for my next article, in which I’ll make the argument for using Windows Server instead of Hyper-V Server.

Oh, and in case you’re wondering which of the two that I actually prefer, well, a guy’s got to have a few secrets.

 

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