Citrix To Offer Tools For Hypervisor-Neutral Virtual Machines

Citrix Systems on Tuesday announced that its Project Kensho will supply open source tools for generating virtualized workloads and running them in a neutral OVF file format. The first sampling of the tools will be in September.

OVF is a standard adopted by the Distributed Management Task Force, a 16-year-old standards body formerly known as the Desktop Management Task Force. Virtualized workloads -- or virtual machines with their applications, also called virtual appliances -- will run under Citrix Systems' XenServer, Microsoft's Hyper-V, and VMware's ESX hypervisors, when generated under OVF.

OVF tools hold out the promise of enabling IT managers the ability to more flexibly manage their data centers. OVF will allow them to generate virtual workloads and run them under whatever hypervisor they choose, or move them between hypervisors.

OVF is a step away from VMware's VMDK and Microsoft's VHD, virtual machine file formats specific to each vendor. Citrix XenServer, in a move aligning itself with Microsoft, has also adopted VHD. The proprietary formats provide a way to store VMs on the hard drive and run them on a particular hypervisor when called up.

OVF goes further than the proprietary formats. It creates a standard way to define a virtual machine so that it may contain several VMDK or VHD files. It also defines the rest of the virtual machine, including the specific hardware, including CPU, disk, and memory, on which it seeks to run. It's this information that gives OVF-based virtual appliances their portability.

"Project Kensho highlights the Citrix commitment to interoperability for virtualization," said Simon Crosby, Citrix's virtualization division, in a statement announcing the upcoming tools. The OVF specification was originally proposed by VMware in February, with XenSource joining in as co-author. IBM, Dell, HP, and Microsoft later contributed to and backed the draft submission to the standards body.

Crosby cited an additional benefit of OVF. It will work with another Distributed Management Task Force standard, the Common Information Model, used to embed management information in software built to DMTF standards. Developers using Kensho tools (Kensho means "enlightened experience" in Japanese), will be following DMTF standards and embedding CIM management interfaces in their virtual appliances, which in turn will allow them to be managed by Microsoft's upcoming Virtual Machine Manager. And VMM will be part of Microsoft's System Center approach to data center management, grafting virtual appliances, hypervisors, and VMs into its purview.

"Because the tools are based on a standards framework, customer are ensured a rich ecosystem of options for virtualization," said Citrix. "Customers can seamlessly move their current virtualized workloads to either XenServer or Hyper-V, enabling them to distribute virtual workloads to the platform of choice."

What it didn't say is that customers' virtualized workloads today are predominantly VMware-based, and the migration ability is aimed at bringing them over to either Microsoft Hyper-V or Citrix XenServer bases. While OVF is hypervisor-agnostic, Citrix's use of it in Kensho tools is to make it serve as a leveler of the playing field and, it hopes, erode VMware's current dominant position. With Hyper-V getting installed around the globe as it ships in Windows Server 2008, the appearance of tools that produce virtual appliances that can move around increases the prospect that some of them will move under Hyper-V.

Crosby in Tuesday's announcement maintained his stance as an advocate of "free, ubiquitous and compatible virtualization, whether from Citrix, Microsoft, or VMware." Of the three, VMware has the highest price. Microsoft will make hypervisors available as a $28 feature of the operating system. At the same time, VMware holds the high ground with Virtual Infrastructure 3 management environment. If companies want more virtualization management than System Center provides, OVF may encourage some migration in VMware's direction.

Crosby also pointed out that Kensho tools will be designed to work with Citrix Delivery Center, or to generate virtual appliances that can be used to deliver application services to business users. Kensho tools will be integrated with Citrix Workflow Studio, a rule-based orchestrator of business services. In the future, some of those services may come through VMs.