Has KVM Won the OpenStack Hypervisor War? (If you can call it a war!)

Has KVM Won the OpenStack Hypervisor War? (If you can call it a war!)

Mastering the potential of the public or a private cloud is probably a hot topic around your IT department’s water cooler. And, where there are conversations about cloud, there are often conversations about OpenStack.

OpenStack provides open source software for creating and managing public and private cloud, with various OpenStack projects managing the compute, storage, network, and a handful of other cloudy aspects. But, there’s a vital piece of the stack that is not part of OpenStack. The compute needs to run somewhere and that somewhere is often (but not always….more on that later) a hypervisor


What hypervisors does OpenStack support?

OpenStack Compute (Nova) runs on a variety of hypervisors, including those from VMware, Citrix, and Microsoft, to name a few. To date, however, OpenStack’s strength-in-numbers lies in KVM. Various surveys (such as this one in OpenStack Superuser) show that the majority of OpenStack deployments, at nearly 90%, are based on KVM.

Why is that? KVM turns the Linux kernel into a hypervisor, and comes standard with many Linux distributions. OpenStack is also a Linux distribution, so the marriage of OpenStack with KVM makes sense. Use your open source software to manage your open source hypervisor! Consequently, the OpenStack community embraced KVM and turned it into the most highly tested and feature rich hypervisor to use in an OpenStack cloud.

So, KVM is the obvious choice, right? It’s free, feature-rich, secure, scalable, and built into many OpenStack distributions. Hang on, not so fast.


Use what you have vs. use the default

Who isn’t using KVM? Likely (if not entirely) the people who already had something else in their data center. Larger organizations with investments in VMware, or other virtual infrastructures, want to retain those investments as they build their cloud. Plus, other hypervisors integrate with additional tools, providing new features that OpenStack alone does not provide for KVM.

And the hypervisor vendors realize this. At least, VMware does, with its recent release of VMware Integrated OpenStack. Perhaps VMware and the other vendors are simply drafting off of KVM while cloud and OpenStack adoption ramp up?


But, wait, do you really need a hypervisor, anyway?

Let’s just throw this idea out there. What about OpenStack without a hypervisor? The most recent version of HP Helion OpenStack (version 1.1) supports bare metal provisioning to HP Moonshot Servers. If you’re new to HP Moonshot Systems, it’s a unique hardware configuration comprised of 45 individual server cartridges packed into a single 4.3U rack-mounted chassis. To me, it’s a hardware geek’s dream.

Can bare metal provisioning open up new use cases for OpenStack? Consider the following. If you want to use OpenStack to manage desktops-as-a-service, you currently must use Microsoft Windows Server operating systems. But, what if HP Helion OpenStack evolved to a) support the HP Moonshot System m700 Server Cartridge, which is designed for hosted desktop loads and b) verify Windows 7 or Windows 8 as an operating system? Suddenly you could deploy and deliver on-demand Windows desktops without jumping through all the Microsoft licensing hoops. Food for thought.


What now?

The question of whether KVM wins the OpenStack hypervisor war may never be answered, and maybe it shouldn’t be. One of the great things about open source software is that it facilitates flexibility, and maybe even fosters the competition that keeps innovation moving. Perhaps KVM is leading, now, simply because it’s the default. But, I’m curious to see what the future holds. How about you?


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