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Making Programs-and Companies-Talk to Each Other

Developments in Virtualization Continue to Push Interoperability

Written by Ron Terry

Microsoft, Windows, proprietary software. Novell, Linux, opensource. The visions could hardly seem more different. So when Novell CEO Ron Hovsepian and Microsoft CEO Steve Ballmer announced a new collaborative relationship between their two companies in a press conference back on November 3, 2006, people took notice. The landmark agreement between the two software giants covered three areas:

  • improvement of the interoperability of SUSE with Microsoft Windows
  • promotion of both products together with a cross-license on the use of patents, and
  • an agreement on marketing.

Three years later, Susan Heystee, at that time Vice President and General Manager for Global Strategic Alliances at Novell, and Ted MacLean, then General Manager for Strategic Partnerships and Licensing at Microsoft, spoke again publicly about the state of the alliance and the two companies' continued efforts towards better interoperability. (See the 3rd Year Anniversary Video at

"Interoperability is a two-way street. If you want your products to talk to each other, you need your software providers to also talk to each other."

-Ted MacLean (O'Reilly Media's Gov 2.0 Summit interview)

As part of these efforts towards interoperability, the two companies have been working together for better identity management, systems management and document format compatibility solutions. Success in these three areas will make it easier to manage mixed Windows and SUSE Linux Enterprise environments. (See "Interop Abilitiy Benefits" at the joint Interop Web site.)

Perhaps above all, however, the efforts have focused on virtualization. They noted that the vast majority of IT Centers are heterogeneous, and run multiple operating systems and products for different platforms. They also said that interoperability efforts are increasingly focused on virtualization. Indeed, as almost everyone in the IT industry knows, server virtualization is the best way to combat the growing trend towards server proliferation. And we all know that more often than not, that produces very low overall utilization. Additionally, as the push grows for internal clouds, there is a real need for truly shared resources across platforms.

"We see this agreement with Microsoft as a fundamental step forward for Linux, and we're strongly committed to driving Linux more firmly into enterprise environments, from the desktop to the data center," said Susan Heystee, vice president and general manager for Global Strategic Alliances at Novell. "For customers who want to use both Linux and Windows, we're going to make life significantly easier. We know customers, partners and the community are looking for concrete results from this agreement."

(Novell's Susan Heystee to Oversee Microsoft Pact in Strategic Partner Role)

The Nuts and Bolts of Cooperation

In April 2006, months before the November 3 announcement, representatives from Microsoft and Novell, met on the MIT campus to coordinate their efforts, primarily in the area of virtualization. The companies needed to produce code that would allow Windows programs to run on the Novell-preferred Xen hypervisor and Linux solutions to run on Microsoft's Hyper-V hypervisor. To that end, not only techs but support personnel were also brought in to help focus on what users really needed when it comes to virtualization.

Core to the alliance's interoperability efforts was the setting up of the Microsoft+Novell Joint Interoperability Lab (JIL). The JIL is a unique facility that develops original technologies while engaging with two different company cultures and that of the open source developer community. As a technical and collaboration bridge between the two companies, the JIL is a model for cooperation between open source communities and proprietary software development companies.

Some of the goals Novell and Microsoft are working towards at the Joint Interoperatiblity Lab (JIL) are:

  • more improvements of SUSE Linux Enterprise Server running on Hyper-V. While the stated performance is only slightly different today, the ultimate goal is parity with the operating system running on "bare metal" and no performance degradation when moving to SUSE Linux Enterprise Server on Hyper-V
  • more Linux Integration Components developments, released to the Linux community
  • System Center Management Packs will continue to evolve with support for advanced Linux support triggers and analysis tools, i.e., analyzing clusters, connectivity, security compliance, update deployments, etc.
  • continued support of Novell for future enhancements to Moonlight, including support for some Silverlight v3 features

(See more at Novell and Microsoft: Building Bridges)

As noted in the National Computing Centre's White Paper, the JIL focuses on new product development and testing for both partners. Its objective is to find and eliminate actual and potential cross-platform or cross-product interoperability problems before they get into products released to market.

Understanding Virtualization and Its Benefits

Of course interoperability is best manifest in virtualization. Likewise, virtualization is increasingly the way to go in large, complex data centers that are striving to avoid server sprawl. Because most IT centers are heterogeneous, Xen on SUSE Linux Enterprise Server and Windows Hyper-V must be truly interoperational. Simply put, virtualization is the execution of software in an environment that is separated from the underlying hardware. The process of virtualization replaces a direct interface between a user and the hardware with a software layer that communicates between the two. Virtualization provides a platform to present a logical view of physical computing resources to an operating system so that multiple operating systems may share a single computer, unaware that it does not have complete control of the underlying hardware. The common theme of all virtualization technologies is the hiding of underlying technical characteristics by creating a logical interface that is indistinguishable from its physical counterpart.

Because system virtualization creates many virtual systems within a single physical system, it provides the following:

  • server consolidation
  • dynamic provisioning
  • virtual hosting
  • reliability, availability and serviceability
  • workload management

And so the benefits of virtualization are clear; system virtualization enables you to:

  • consolidate systems, workloads and operating environments
  • optimize resource use, and
  • increase server flexibility and responsiveness.

Interoperability and Virtualization

Both Xen and Windows Hyper-V use hypervisors, which are virtualization platforms that allows multiple OSes to run on a single host computer. The main job of a hypervisor is to provide isolated execution environments for the guest OSes and to control access to the underlying hardware. There are two types of hypervisor:

  • Type I: (native) - runs on the hardware without another layer between it and the hardware. It manages all the hardware resources for the various operating systems running on top of it.
  • Type II: (hosted) - runs on top of a host operating system and is the communication layer between the host OS and the various guest operating systems that are running virtually on top of the Type II hypervisor. The host OS provides I/O sharing and a management interface to the hypervisor.

Whether you plan to deploy SUSE Linux Enterprise Server virtual machines as guests on Hyper-V hosts or Windows virtual machines as guests on Xen hosts, you need to understand what it takes to make those operating systems work with the best possible performance. Both virtualization technologies have interoperability components that you need to be aware of. These are:

  • Hyper-V Linux Integration Components (IC) (See Figure 1.) This driver code was designed to enhance the performance and usability of Linux guest operating systems running on Windows servers so that Linux virtual machines can run in enlightened mode.
  • SUSE Linux Enterprise Virtual Machine Driver Pack. This driver pack contains paravirtual disk and network device drivers for several third-party operating systems. They enable hosting of the unmodified guests on top of SUSE Linux Enterprise Server 10 SP2 and Xen 3.2 or later.

The Unlikely but Revolutionary Collaboration

Improving interoperability, especially in the area of virtualization, requires continued collaboration. The technical and support issues users continue to face with networking show the importance of the collaboration between Novell and Microsoft. Since the Novell/Microsoft relationship began almost four years ago, Novell has been writing drivers for Windows to run on top of Linux and Microsoft has been writing and maintaining drivers that allow SUSE Linux Enterprise Server to run on top of Windows. All along, work in the JIL has focused on fixing problems before software is released to provide truly seamless interoperability.

"The technical collaboration between Microsoft and Novell has enabled us to reduce overall costs while increasing cross-platform manageability. This means we're able to deliver more consistent quality of service to our customers at the best price possible," said Dr. Happy Sithole, Ph.D., director of South Africa's Centre for High Performance Computing. "In addition, migrating to the Linux support offered by Novell was a great decision for us. Not only do we get the interoperability advantages of seamless integration between our platforms, but we also have the confidence of knowing we are supported by two world-class vendors."

("Microsoft and Novell Collaborate to Deliver Hybrid Options for High-Performance Computing")

So what's in it for Microsoft and Novell to cooperate so closely in these areas? In the end, it is the question of "coop-etition." While the two companies continue to compete in many areas, a pragmatic approach to the market requires that they work together to keep their customers satisfied. Because customers are using both platforms in heterogeneous data centers, working together in the area of virtualization but also in systems management and in office and document format compatibility, interoperability is good business, with joint customers growing by as much as 58 percent.

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