With all the virtualization platforms out there today, you don’t have to choose just one. A lot of infrastructures now run multiple virtualization platforms, making it easier for admins with specialized skills to manage the platforms they’re familiar with. Plus, it helps data centers avoid vendor lock-in.
But at the same time, using multiple virtualization platforms can complicate virtualization management. There aren’t many management tools available that can manage across different platforms at once. You end up needing more virtualization management tools and having to keep track of many disparate virtual machines (VMs) with different requirements.
There is also the issue of converting between vendors’ virtual disk formats. Expert Sander van Vugt discusses this virtualization management challenge and other pros and cons of running multiple virtualization platforms.
What are some reasons an infrastructure might run multiple different virtualization platforms?
Sander van Vugt: From what I see with my customers, there are some larger companies that have data centers with different groups of administrators responsible for different kinds of servers. For example, a Windows Server-based group of admins, they like to use Hyper-V because it’s included in Windows. The larger companies often have a Linux or Unix install base as well. And Oracle also has its own virtualization solution, so Oracle people might choose Oracle VM. What I see from companies that do have different virtualization platforms is that it’s because the groups of administrators can function like little islands -- everyone making their own decisions. That’s the main reason why.
Is it common for data centers to run multiple virtualization platforms?
S.V.: It depends on the size of the company, but yes, I think it’s pretty common.
What are some benefits of using multiple virtualization platforms?
S.V.: If you have Linux-skilled people, for example, those people tend to be really into Linux-based virtualization solutions, because that’s the environment they know how to handle. And it’s so much easier for them to learn how to work with that solution than to learn something entirely new. Imagine that a company tries to standardize on Microsoft Hyper-V virtualization, and then within the company there are Linux admins who don’t do anything with Hyper-V. If they need to be responsible for their own virtualized servers, that’s not going to work.
Plus, it’s a huge investment for a company to put their employees through training courses. Using multiple virtualization platforms can therefore have some cost benefits. There are also virtualization management benefits, because it’s so much easier for admins to do their work based on solutions they’re familiar with.
What are the challenges of cross-platform management?
S.V.: In companies where different groups are responsible for their own virtualization solution -- those “islands” -- management is not very complicated, because each group takes care of its own aspect of virtualization. For example, the Windows people may take care of Hyper-V virtualization and the Linux people may take care of KVM virtualization. It’s a big challenge, though, when companies decide they want to integrate their virtualization solutions. They have a problem, because it’s not really doable with the proprietary solutions such as VMware vCenter, Microsoft’s management environment or Red Hat Enterprise Virtualization. You can’t just integrate platforms with these tools.
Are there any tools that can single-handedly manage different platforms?
S.V.: From my experience, I’ve only seen one tool that does a pretty good job of integrating different virtualization solutions: PlateSpin Orchestrate, which is currently owned by Novell. It’s not that easy to set up, but once you set it up properly, it’s capable of integrating the most common virtualization environments.
But surprisingly, there doesn’t seem to be much else on the market. I think Hewlett-Packard has something they’re using to integrate different platforms, but apart from that, there’s mostly silence. I’m not aware of any major player that has a solution that can manage all virtualization platforms.
Theoretically, you could manage Hyper-V and VMware with the PlateSpin tool?
S.V.: I’ve seen it done with Citrix XenServer and VMware, and it does also support Microsoft Hyper-V. But even with PlateSpin, you do need a plug-in for the different virtualization platforms.
Different vendors’ virtualization platforms include different virtual machine disk formats. Is it difficult to convert between disk formats if you’re running multiple platforms?
S.V.: There is some work being done in this area. There’s the Open Virtualization Format (OVF), a standard that multiple vendors have been adopting. That’s going to make things easier. It presents a challenge, though, if you have an older disk format from a specific vendor. In those cases, you’ll need to convert disk formats.
Converting virtual disks is fortunately not that difficult, because a disk is just a collection of data blocks, and a disk in one environment is much like a disk in another environment. The only difference is in the meta data, which describes what’s in those data blocks and where people can find the data. So it’s not rocket science. That’s not the huge issue here.
So converting disks is pretty easy?
S.V.: I don’t like the word easy, but it’s not the hardest thing to do. Anyone who wants to try it can write an appropriate tool to do the conversion. Red Hat Enterprise Virtualization 3.0, which comes out later this year, will include a pretty powerful tool that can handle many different formats and convert disks to their own Red Hat standard. So, it’s almost easy.
What are some other challenges people run into when using multiple virtualization platforms?
S.V.: The major challenge is that the virtualization landscape is changing so fast. Sure, VMware is the market leader, and we all know that, but we also see other vendors trying to get into the market and develop their own solutions. That means the integrated management solutions that may be accurate for virtualization formats available today may be completely inaccurate for handling those formats properly tomorrow.
Plus, integrated virtualization management platforms will always run a couple of months behind the actual market development. So that’s a challenge. Still, if something is released today, it does take time for the market to adopt the solution. In theory, it’s a challenge, but in real life, that problem tends to sort itself out automatically.