Citrix XenServer is now open source

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Just in case you missed it, XenServer is now open source.
It’s confirmed by the Citrix CTO of Virtualization and Management division Simon Crosby, who answered a question about this topic on

Citrix XenServer is a commercial implementation of the Xen open source hypervisor, as much as Oracle VM Server and Novell SUSE Enterprise Linux Xen.
XenSource, the company which sponsored the Xen project in its early days and that developed XenServer, has been acquired by Citrix in August 2007 for $500M.

Citrix first decided to give away XenServer for free (February 2009) and then announced its plan to release it as open source (October 2009).

The source code is now part of the XenServer 5.5 Update 2 download package that is available online.
To see the source code ISOs you have to log on:


As expected, the source code doesn’t include XenCenter, the XenServer management interface, which is a Microsoft .NET client GUI, and the hearbeat component required for the High Availability feature.

The open source version of XenServer is the foundation of the Xen Cloud Platform (XCP) that was unveiled in August 2009.
In his comment on, Crosby clarified that Citrix will first contribute to the hypervisor code that is part of the XCP, and then will derive from it future versions of XenServer (like the imminent codename Midnight Ride).

The question is: what Oracle and Novell will do with their own implementations of Xen now?

Update: The source code ISOs are also available without registration here.