Red Hat Admits Delay In Including Virtualization Technology In The Linux Kernel
Red Hat Will Support Xen Virtualization Project "Out Of Tree" For Red Hat Enterprise Linux Version 5
Mar. 16, 2006 08:00 AM
The move to weld virtualization technology deep into the Linux kernel is facing setbacks. Despite earlier optimistic predictions by Red Hat executivess and others in the community that the work would take just a couple of months, they say now that the technology is still "far from ready for inclusion in the kernel." The problem lies in rapid changes in the Xen Project's virtualization code.
An emerging key to many enterprise consolidation strategies, virtualization lets IT managers run multiple copies of Linux on a single server. For Red Hat, a big part of the strategy is making virtualization an integrated part of the Linux system itself, so that the kernel understands that it is virtualized and can better participate in its management.
"I am an eternal optimist, but I really did not appreciate how extensively and rapidly the Xen code is changed," said Brian Stevens, Red Hat's chief technical officer at the launch of the company's Integrated Virtualization strategy in San Francisco on March 14.
"There are still hundreds of change sets taking place on a weekly basis, with a lot of work still left to do. While we have tried to focus less on functionality and more on stability, even with Xen 3.0, which was released in December, the code is still far from ready for inclusion in the kernel," Stevens said.
In October of 2005, Stevens took up the task of driving forward the merging of Xen into the Linux kernel, an initiative that had previously run out of steam with no one at the helm. He said at the time, "Red Hat is now stepping forward … We would like to have the Xen virtualization technology submitted for inclusion in the Linux kernel in the next two months. I don't think it's a long-term project at all." The goal was to make virtualization and its management part of a Linux system, "so this is not just maturing the technology, but having the operating system itself, the kernel itself, be intimately aware that it is being virtualized so that it participates," Stevens said at the time.
However, it is now more likely that individual components of the Xen virtualization technology will be merged into the kernel over time, starting with the Xen interfaces, rather than all of it as a single submission, Stevens said. This would also mean that the Raleigh, N.C. company will have to support Xen "out of tree" for RHEL (Red Hat Enterprise Linux) Version 5, which is scheduled for general availability before the end of this year and will feature fully integrated virtualization. That is because the Xen virtualization technology will not have been submitted to the Linux tree by that time, Stevens said. "Each time there is a new rev, our engineers have to merge the Linux tree with the Xen tree, and we then spend a couple of weeks on stabilizing this each time, which is a lengthy, time-consuming and painful process," he said.
While pricing and packaging for RHEL 5 has not been finalized, Stevens said he does not want to force the virtualization technology on those existing customers who may not want it, so he is looking at a separate server solution product that will include the virtualization technology. This new server solution would be priced on a subscription basis like Red Hat's other products, but the pricing model would allow unlimited customer use, so as to make virtualization and RHEL use pervasive, he said.