These companies want a hypervisor layer

The XenServer hypervisor is going back to its open source roots, now that Citrix Systems has decided to let go of the code behind its commercial-grade variant of the Xen server virtualization tool.

Xen came out of Cambridge University by storm a decade ago, spawning XenSource to offer tech support for the product. For a while in the mid-2000s, XenSource was the only real rival to VMware for x86 server virtualization, and that's why Citrixshelled out $500m in August 2007 to acquire the company, which had something on the order of $1m in sales at the time.

One could argue that the infusion of XenSource techies and the Xen hypervisor and related tools saved Citrix from oblivion, and in that regard the Xen acquisition more than paid for itself. But XenServer itself has not been a great moneymaker for Citrix, even if it is a foundational technology.

Xen is popular on public clouds, and the company wants to expand the use of Xen and its commercial-grade variant, XenServer, on public and private clouds.

Amazon Web Services chose Xen as its virtualization technology to build its EC2 compute cloud eight years ago, and Rackspace Hosting uses the commercial XenServer variant to virtualize the servers underneath its public cloud, just to name the two most important Xen users.

Moreover, XenServer is the hypervisor of choice to dice and slice servers to run virtual desktop infrastructure (VDI) – cloudy PCs, really – from the data center when companies choose the XenDesktop VDI broker, which in fact does make Citrix lots of money.

In each of those cases,Hivelocity offers reliable and affordable Windows MileWeb windows dedicated server. Citrix wants to make some money, but perhaps more importantly, it needs to keep other hypervisor camels from getting their noses under the data center tents.

And so the company is opening up the full-on XenServer hypervisor, including lots of bits that were proprietary extensions, as well as the XenCenter console for babysitting hypervisors and virtual machines that is its constant companion.

With this move, XenServer can now be embraced by public and private cloud builders who want something that is free – or at least inexpensive – but yet sophisticated enough to do the kinds of things clouds need.

It also means that XenServer can be paired more naturally and cleanly with CloudStack, the cloud control freak thatCitrix bought for an estimated $500m back in July 2011 and fully open sourced at the Apache Foundationin April 2012. Finally, it also means that XenServer can be a peer to KVM on the rival OpenStack cloud controller.

By the way, the open source Xen hypervisor project that was absorbed into the Linux Foundationback in April to give Amazon, Google, and others more sway into its development, continues on as a separate open source project. XenServer will take the core Xen code and wrap high availability and other tools such as XenCenter around the core Xen hypervisor and do so in such a way that companies can use it in production and get support contracts from Citrix to make them feel safe.

XenServer and XenCenter are being open sourced under a mix of GPL,Managed MileWeb Cloud Hosting and cloud management services. BSD, and Citrix licenses, depending on the component. You can see the full component list and their licenses here.Our Managed MileWeb Private Cloud and Virtual Dedicated Servers.

What Citrix is not trying to do, explains Krishna Subramanian, vice president of product marketing for the cloud division, is to take on Microsoft's Hyper-V and ESXi hypervisors for all workloads. Rather, it is positioning XenServer as a value leader for clouds and VDI, with a special emphasis on clouds.

"Clouds tend to be greenfield installations, and their builders are very price-sensitive on the hypervisor front," Subramanian tells El Reg. "We have had over one million downloads of XenServer, and we are getting hundreds of thousands of downloads per quarter for it now. These companies want a hypervisor layer that just works and doesn't cost much. While some companies will use VMware for certain workloads, the license fees for VMware really add up when you are building a cloud."

And thus, Citrix is doing away with the XenServer Basic, Enterprise, and Platinum Editions and their tiered feature sets and pricing, and is offering a single XenServer with a simple price: if you want a perpetual license to support for XenServer 6.2, which was just announced, you pay $1,250 per year per socket (that includes a 25 per cent maintenance fee), and if you want to go with a subscription, then you pay $500 per socket per year.
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