Why Linode moved to KVM

Linode, a cloud hosting provider, turned 12 last week. The company is celebrating its anniversary by launching the general availability of KVM Linodes to customers.

Both KVM and Xen are Open Source projects released under a GNU GPL licence. While Xen has been around since 2002, KVM is relatively new and is maturing fast thanks to the backing of some industry heavyweights.

KVM was initially formed by Red Hat in alliance with IBM. As a result, KVM does get more love from the Red Hat infrastructure. The company also developed oVirt, a web application to manage KVM, though it does allow you to manage other virtual machines running on Xen or Oracle VirtualBox as well.

Interestingly, both KVM and Xen are now Linux Foundation projects but the new kid is gaining momentum at the cost of Xen, and more players are moving to KVM. To better understand Linode’s move to KVM, I interviewed Ricardo Feliciano, Developer Evangelist at Linode.

What was the main reason behind moving away from Xen and adopting KVM?

Feliciano: When we spent $45 million to upgrade our commercial-grade servers to the very latest technology in 2014, the virtualization layer, in this case Xen, kept us (and by extension, our customers) from tapping the inherent speed and computational power of the hardware. Switching to KVM removes this layer and puts customer operations as close to the Linux kernel as possible. Consequently, our servers will now deliver optimum performance; customers should realize improvements from 25 to 300 percent.

Linode is well regarded within the Linux community, what kind of engagement is there between the company and open source? Do you contribute to any open source projects?

Feliciano: The engagement with the Linux community is strong. We have contributed to the Linux Professional Institute and are a gold sponsor of the Debian project to fund its LTS program. We attend many Linux conferences, including SCALE, SELF and the upcoming LinuxCon North America in Seattle.

Linode has donated more than $1.2 million dollars in surplus servers to nearby colleges and universities in an effort to bolster open-source curriculum on-campus at TCNJ, NJIT, Rowan University and Monmouth University. We are working with Atlantic Cape Community College to establish a Linux curriculum that will prepare students for Linux certification exams. These on-going and expanding efforts are part of our IT Workforce Preparation Initiative (ITWP).

Moreover, our “softer” promotion of Linux includes scheduling our community advocates to preach the “gospel of Linux” and open-source to various user-groups throughout the country. When we participate in hackathons, such as AngelHack, LA Hacks, and PennApps, Linodians encourage the use of Linux.

It’s our intent to promote the greater good of open source wherever we go and whatever we do; if not with funds, then with action. In our estimation, the more Linux, the better.

What clear advantages are there with KVM that justify this move?

Feliciano: In a word, “performance.” Our internal UnixBench scores increased three-fold (~800 SBIS on Xen to ~2400 SBIS on KVM).

In another word, “versatility.” Having default paravirtualization along with fully virtualized guest-virtualization will let users run alternative OSs like FreeBSD, BSD, Plan 9, Windows, even Amiga.

The final word: under Xen, we found it challenging to support varied architecture such as 32-bit Linodes and non-Linux OSs; KVM mitigates those challenges.