Xen comes back to CentOS with Xen4CentOS
As part of a concerted effort by the Xen project, the Citrix open source teams, the CentOS developers and teams from GoDaddy and Rackspace, the Xen virtualisation system is once again available for users of CentOS, the Linux distribution that is built from the source of Red Hat Enterprise Linux (RHEL). The Xen project has been run under the auspices of the Linux Foundation since Citrix transferred leadership of the project in April.
After Red Hat dropped Xen in favour of its preferred KVM hypervisor with RHEL 6 in 2010, using the software in a maintainable manner on RHEL, and consequently CentOS, was almost impossible. As Lars Kurth, Xen community manager for Citrix, puts it, talking to the Linux Foundation's Linux.com: "This has been quite painful for Xen users; CentOS has been and still is one of the most popular Linux distros for Xen users". To solve this problem, the Xen4CentOS project has released a number of RPM packages in a dedicated repository, providing a complete Xen-4.2-based virtualisation stack on current CentOS releases.
The repository ships a Linux kernel based on the 3.4 long term support (LTS) release with custom patches by the Xen4CentOS contributors that will be maintained for two years. According to the release notes for the project, the packages can be considered production ready and have been tested on "hundreds of hypervisors, some of them running hundreds of VMs, in production grade deployments".
The developers point out that Xen4CentOS is currently only available for 64-bit CentOS 6 installations and that "there are no plans to build it for 32bit support in this version," but that they will re-evaluate once Xen 4.3 has been released. Additionally, SELinux will have to be disabled on the Dom0 for some features like qemu-xen and blktap backed storage to work.
More information on how to use the Xen4CentOS repository is available on a QuickStart page on the CentOS wiki.
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