Brokering connections

The VDI field is wide open at the moment, with dozens of vendors selling fresh solutions. Citrix has released a functional broker package and is working on improving its architecture to fully integrate VDI into its offering. Leostream has released a solution that works with VMware called Hosted Desktop Connection Broker, which functions in much the same way, offering VDI connectivity to selected thin clients (though it borrows third-party hardware to provide SSL support). Dunes’ VD-O offering is similar, whereas Sun’s Sun Ray-based broker and the workSpace product developed by Propero (recently acquired by VMware) offer integrated SSL plus an array of other features.

VMware is in the game, too, with its VDM broker, which shares most of the above features. All of these brokers provide such features as single sign-on and shared pools; some also offer automated pool provisioning and application publishing. These products are still in their infancy, and are definitely VMware-centric, designed to be used in environments specifically built around VMware’s VI3 virtualization framework.

Some of the more advanced brokers come from Provision Networks and 2X. These tools can serve as VDI brokers, but can also extend beyond the virtual realm, offering desktop session connections to VMware clients, VirtualIron clients, Microsoft Virtual Server clients, as well as physical hardware, such as blade systems. Some even have the capability of connecting to Citrix MetaFrame, Microsoft Terminal Services, or TN3270 sessions. In this fashion, they serve as a general clearinghouse for all thin-client computing.

With these tools, it’s possible to create a heterogeneous thin-client computing environment built around whatever technology is the best fit for the user. This is a very attractive proposition for infrastructures with existing thin-client computing installations.

With a global connection broker, it’s possible to build policies that dictate different frameworks for different user sessions. Heavier users that require more robust and responsive sessions can be directed to a session running on a dedicated blade in a blade chassis, while lighter users are directed to a VDI session running under VMware. A specific user class may be already built into a Citrix MetaFrame farm, and thus, those users are connected to a Citrix server for their desktop session. This approach can be an invaluable tool to bring the promise of a complete thin-client infrastructure to reality.

Virtual dawn
For many companies, virtualization has barely begun. Perhaps there’s a single box running VMware Server as a proof of concept, or a pilot project involving a commercial or open source hypervisor. But as virtualization proliferates on the server side, the desktop side will open up. According to VMWare’s Chen, “We’re starting to see our customers becoming comfortable with their virtualized back end, and they’re looking to do the same on the desktops with VDI.”

Moreover, some of the benefits intrinsic to server virtualization are transportable to the desktop. VM migration between servers, for instance, can be used in a VDI sense to move active desktop sessions from one spot to another in order to bring a server down for maintenance. This equals zero downtime for the end-user and eases administration complexity. Also in the mix are the high-availability features found in VMware and VirtualIron. Should a physical server go down unexpectedly, the desktop VMs running on that server can be restarted automatically on another server.

Superior load balancing is another VDI bonus. Traditional Citrix MetaFrame and terminal services farms can use any of several load-balancing methods, but once a client is connected to a specific server, that connection stays put. In a VDI implementation, that user’s session can move around among different physical servers without affecting the session, resulting in much more fluid load balancing.

Right now, any customer who rolls out VDI in a production environment is the very definition of an early adopter.  There are many missing or incomplete pieces to this puzzle, but the companies with a stake in this game are moving at a fast clip. Several broker and hypervisor vendors are looking at the last quarter of 2007 to release brand-new VDI frameworks, and so are the thin-client vendors. The heyday of the virtual desktop is just a glimmer on the horizon, but the future definitely looks bright.