Red Hat Admits Virtual Holdup in Linux Kernel

By Peter Galli  |  Posted 2006-03-14

Red Hat Admits Virtual Holdup in Linux Kernel

The move to weld virtualization technology deep into the Linux kernel is stuck on the workbench.

Despite earlier optimistic predictions by Red Hat execs 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 is that the Xen Projects virtualization code wont stand still for the process.

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," Brian Stevens, Red Hats chief technical officer, told eWEEK at the launch of the companys 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 told eWEEK at the time that "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 dont think its 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.

Click here to read about why Red Hat is pushing to have Xen virtualization technology added to the Linux kernel.

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.

Andrew Morton, the current maintainer of the Linux 2.6 kernel, who works for Open Source Development Labs in Beaverton, Ore., also told eWEEK that he was not hearing much on the Xen submission front. "I dont know what people have been doing lately—nothing has come my way," he said.

Click here to read more about the Linux kernel development process.

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.

Next Page: Unlimited-use pricing model encourages virtualization.


-Use Pricing Model Encourages Virtualization">

This new server solution would be priced on a subscription basis like Red Hats other products, but the pricing model would allow unlimited customer use, so as to make virtualization and RHEL use pervasive, he said.

Tim Yeaton, Red Hats executive vice president for enterprise solutions, agreed, saying the goal was to make virtualization technology easy to consume and utilize.

As such, it is unlikely that Red Hat would price this on a per-instance basis, he said. Rather, the solution will probably be priced on a platform basis so as not to let pricing stand in the way of the pervasive adoption of virtualization technology in RHEL 5, he said.

Meanwhile, this comes as Microsoft Corp. is pushing its own virtualization products and recently relaxed some of its licensing requirements around Windows Server 2003 to facilitate more pervasive adoption and use of those technologies.

In addition, Stevens dismissed—at least for the time being—analyst speculation that Red Hat was looking at developing a set of management tools to take advantage of the Xen virtualization capabilities, which could lead to it competing with its partners like IBM.

To read more about Microsofts move to simplify its Windows Server licensing, click here.

While that could well happen a few years down the line, there are currently no such plans and no secret projects around this taking place within Red Hat, he told eWEEK.

In fact, Red Hats priority is helping its partners to compete in the management space, and that means allowing them to interface to the virtualization-enabled version of RHEL, he said.

"The first step in that process is to design a set of stable APIs and ABIs [application binary interfaces] for virtual machine control," Stevens said.

These APIs, as for resource management and policy-based management, would not be Xen-specific and would be licensed in a way that also allowed them to interface with proprietary code, Stevens said.

Asked about Red Hats business relationship with XenSource, Stevens said this was something the companies were working on and, again, stressed that Red Hat was not planning to try and develop a management solution that would compete with XenSource.

According to Stevens, some 80 percent of customers were "totally jazzed" by virtualization, while the other 20 percent were not interested. But the integration of the technology into Red Hats products is still at an early stage, he added.

Red Hat will make Fedora Core 5 available in March, as early as the week of March 20. Fedora Core 5 will contain a preview of Red Hat Enterprise Linux virtualization technology and will "create a core of use around virtualization technology," he said.

Then, in the summer of 2006, Red Hat will make its Virtualization Migration and Assessment Services available along with an Enterprise Virtualization beta. Red Hat Enterprise Linux Version 5, which is scheduled for general availability by the end of 2006, will feature fully integrated virtualization, he said.

Even Red Hats chip-set partners, Intel and Advanced Micro Devices, are also both at a proof-of-concept stage with regard to the use of virtualization technology internally, Stevens said.

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