host/guest arrangement. However, in 2008, Ubuntu made a decision not to
support Xen. Instead, the Ubuntu community has focused its efforts on KVM.
This is not a value statement that one is better than the other; it only means
that KVM seemed to be a better fit for the needs of an Ubuntu developer
community that did not have the resources to give quality support to two
similar virtualization platforms.
It appears to be possible to run Xen on Ubuntu, but there are no guarantees.
For this reason, many choose to use one of the Linux distributions that use
Xen as the primary virtualization platform, such as SUSE, Red Hat, or
CentOS, if Xen is preferred.
References
http://www.linux-kvm.org—The main page for KVM
http://www.virtualbox.org—The main page for VirtualBox
http://www.vmware.com—The main page for VMware
http://www.xenproject.org—The main page for Xen
http://www.xenproject.org—The main page for Xen