In-Depth

Q&A on Microsoft Virtualization, Part 4

Ben Armstrong discusses Nano Server and the Trusted Platform Module.

• By Paul Schnackenburg
• 12/14/2015

More on this:

• Part 1
• Part 2
• Part 3
• Part 5
• Part 6

Contributing Editor Paul Schnackenburg continues his interview with Ben Armstrong, Microsoft's program lead for Hyper-V.

Paul Schnackenburg:  Now that Nano Server is coming and it is so small, I can remember back in the day... so this is a good five, six years ago, when we talked about booting your hypervisor device off a flash disk or a USB stick or something, because that way you wouldn't even need to deploy the operating system. You just plug a stick in or something. Are you looking at that scenario at all?

Ben Armstrong: There's a lot of options that are being looked at. To be honest, I don't know where that one's at, like the detail here is everything that you just mentioned absolutely works. It's not my team that gets to make the support statement and what is and isn't supported.

So actually the more interesting model we've been chatting to people about is once you're on Nano Server, having a model where every time you boot your computer you do PXE deployment from Windows Deployment Services. It's actually kind of interesting because a Nano Server deployment is 450MB and it's an interesting thing to re-boot the box; every time it re-boots it's just laid down a new OS.

PS: And then you just need to patch your central golden image and you're good to go, always up to date. I like that. So circling back to Shielded VM, because that's the very first one you mentioned, what do you think the uptake of that is going to be, as it requires TPM [Trusted Platform Module] Version 2 chip, given that that hardware is really new. Can you also compare the TPM Version 2 assurance with the AD Group-based assurance?

BA: So you've asked a bunch of questions there. The first one is to be very blunt and transparent: we're not expecting massive uptake in the first release. You know, the reality is we do have the hardware requirements. It's also at this point in time quite complicated to set up and so on.

We definitely have hosting companies who are already deploying it and trying it out in evaluation and they see the potential benefit of offering different security levels and be able to tell their customers  is "Hey, I have Shielded Virtual Machines." So we are expecting to see some uptake especially in the hoster market. That said, the two key points for us is, one, the real importance here is moving the conversation forward and getting people off of "This is a problem you can never solve," to understanding, hey, this is actually a problem that's technically solvable.

So my expectation is we're going to be iterating on that over the next couple of years and making it easier for people to use, while maintaining the security bit. On the requirement for TPM 2.0, yes, once again this is one of the reasons why we're pushing to get it out, and it's a conversation we've been having with a whole lot of OEMs where ... it's a conversation to have: we're working on the next version of Windows 10 and it's going to have great features that require a TPM 2.0, so you should put that in your hardware and they're saying we don't have customers asking for it today and that's a cost, and so there's a chicken and egg thing.

So at this stage most OEMs do have Server offerings with TPM 2.0 in it. It's not what you get by default. You do have to go out and ask for it. Our expectation is that we'll slowly change that as we iterate on the technology. I mean, we had a similar journey on laptops. It used to be that TPMs on laptops were an esoteric thing ... I know when it first came out, it was a bit like we have a TPM requirement and people were like, "My laptop doesn't have one," and so on, and there's an iterative process where we have to work with our hardware partners to make sure that everyone gets the value.

On the security promise … the TPM solution is definitely more secure than the AD solution. Now, that said, it's one of the huge debates that we have on the team … It's actually one of the things if you dig into the experience that we've built around Shielded Virtual Machine, there are about half a dozen ways that you can configure this at this point in time, and it's really about what protection profile do you want?

So on the weakest end of the spectrum, you can go into Hyper-V on Windows Server 2016, just turn on a virtual TPM and say, "I'm going to use it for BitLocker, and we don't do any of the protection from the host administration, and we don't do a whole bunch of things." It's easier to set up and all it really gives you is data encryption. Now the reality is, though, that from a lot of industries that's all they need.

Then we have all the way to the other end of the spectrum, where we do the full protection against host administrator, we do the full attestation path, and so on, and there are some industries that need that as well.

On the engineering team, we have this aspirational goal that we would love to get to a world where one day every virtual machine is a Shielded Virtual Machine. We think that would be great. Right now today where we're at with the technology, there are too many trade-offs and too many decisions that we need to allow customers to decide like, okay, no, I'm going to have this little protection on this virtual machine and we'll start with that.

So, coming back to the TPM versus active directory, you know that they both work, though one is definitely... from the computer science one being more secure than the other. However, for different customers, different requirements, different scenarios, each one's going to make sense in its appropriateness.