Why centos6.0 removes the support of xen

Question

In centos5.x, you can simply install xen by yum, but this can't be done on centos6.0.

So why centos6.0 removes the support of xen?

Answer 1

CentOS is derived from RHEL by recompiling source material and removing copyrighted work, etc. As such, CentOS is entirely dependent on RedHat's work. RedHat makes the decisions about what technologies it, as a commercial entity, is prepared to support, and so what ends up in RHEL, and consequently in CentOS.

Xen was removed from CentOS because RedHat chose to remove it from RHEL.

RedHat made the commercial decision to choose to put its support and resources behind the KVM project, instead of Xen. The reasons for this choice are debatable but are likely to include both technical and political reasoning about project governance.

XenSource, as the primary entity contributing to the Xen Project around 2006, made the decision to ship their commercially-supported version of Xen as an appliance (ie. an entire OS), rather than as software that could be installed on a user's existing Linux distro such as RHEL or SLES. It pursued this approach in order to control its own destiny -- the alternative, taking the distro software approach, would have had serious consequences for XenSource's ability to QA the software and have imposed hard external constraints on its software release cycle.

Citrix then bought XenSource, and the appliance strategy continued, as it does to this day with XenServer.

Some time after Citrix bought XenSource, RedHat purchased Qumranet, a commercial entity with engineers contributing to KVM. At this point, RedHat switched allegiance from Xen to KVM.

It is still possible to use Xen with CentOS, in both a commercially-supported fashion, by using Citrix XenServer, and in an enthusiast home-brew fashion with xen.org and the Xen Cloud Project. See http://xen.org/download/xcp/index_1.5.0.html or try asking around on the xen-users mailing list.

Answer 2

Because it has been superseded by KVM.