XenServer is an open source project and community managed by Citrix. The project develops open source software for securely running multiple operating systems and applications on a single device, enabling hardware consolidation and automation to reduce costs and simplify IT management of servers and applications.
Citrix provides a commercial support and services for XenServer under an enterprise license agreement for those users who need dedicated support.
Xen originated as a research project at the University of Cambridge, led by Ian Pratt, senior lecturer at Cambridge who co-founded XenSource, Inc. with Simon Crosby also of Cambridge University. The first public release of Xen was made in 2003.
Xen 1.0 was officially released followed a short time later by Xen 2.0. At the same time, Ian Pratt and several other technology leaders founded XenSource, Inc. to convert the Xen hypervisor from a research tool into a competitive product for enterprise computing. As part of the corporate strategy, the Xen hypervisor remained an open source solution.
Widespread adoption of the Xen hypervisor took place when Red Hat, Novell, and Sun all added the Xen hypervisor as their virtualization solution of choice. The development community also accelereted the capabilities of Xen with the Xen 3.0 release.
Microsoft and VMWare adopted the concept of Paravirtualization, first introduced by the Xen community.
October 22, 2007, Citrix Systems completed its acquisition of XenSource, and the Xen project moved to http://www.xen.org/. This move had started some time previously, and made public the existence of the Xen Project Advisory Board (Xen AB), which had members from Citrix, IBM, Intel, Hewlett-Packard, Novell, Red Hat, Sun Microsystems and Oracle.
April 15, 2013, it was announced that the Xen Project was moved under the auspices of the Linux Foundation as a Collaborative Project. The Linux Foundation launched a new trademark for "Xen Project" to differentiate the project from any commercial use of the older "Xen" trademark. A new community website was launched at http://xenproject.org/ as part of the transfer. Project members at the time of the announcement included: Amazon, AMD, Bromium, CA Technologies, Calxeda, Cisco, Citrix, Google, Intel, Oracle, Samsung, and Verizon
June 24, 2013, Citrix announced the open source XenServer project with the goal of delivering their formerly proprietary product XenServer as an open source product with greater input and participation from the open source community.