I have deployed several VDI solutions in test scenarios and experienced firsthand some of the integration challenges presented by today's technologies, the first of which is determining the how well technologies work together to build a workable solution. That means you'll have to carefully research the various components before combining them.
That said, there are still common, necessary components needed for a VDI deployment, including:
- A virtualization platform (such as Microsoft's Hyper-V or EMC VMware's ESX server)
- A communications protocol (such as RDP or ICA)
- A virtual management platform to provision and manage pools of virtual machines
- A session broker to assign users to VMs and maintain connections
- A client device (such as a thin client, a zero client, a PC running a thin client, or a PC running a compatible browser)
What deters most administrators is the complex ecosystem of VDI elements, which often come from a variety of vendors. That adds to the overall complexity of deploying and managing a VDI solution. Administrators also have the option of adding other components, such as application virtualization (which speeds the deployment of applications to virtual machines), as well as profile and data redirection technologies (which help to synchronize sessions and redirect users to the proper virtual machines if a session is interrupted).
I've found that application virtualization products, such as VMware ThinApp, can simplify provisioning of new virtual desktops by autoinstalling line-of-business applications for the user.
Further muddying the waters is the fact that virtual machines come in two flavors: a Type 1 hypervisor and a Type 2 hypervisor. A Type 1 VM runs the hypervisor as the actual machine's operating system; in other words, the hypervisor is loaded as part of the software boot process, then the virtual machine launches to run its virtualized desktop, including the desktop OS. A Type 2 virtual machine runs as an application installed onto the desktop's native operating system, so another layer of software has been added to the mix. PCs and servers equipped with the latest virtualization-aware CPUs can run Type 1 virtualization, as well as Type 2 if a compatible operating system is installed. A good example of a Type 1 virtualization product is VMware's ESX server, and Microsoft Virtual PC is a good example of a Type 2 hypervisor.
Thin clients and zero clients cannot run hypervisors at all; they lack the native processing power and hardware. Thus, they rely completely on a server to physically run any software or applications.
The endpoint is critical to your VDI strategy
Although VDI is all about moving the desktop back into the data center, the endpoint still plays a significant role in determining how to deploy VDI. Before wandering down the path to VDI nirvana, administrators need to do a little due diligence.
VDI's complexity doesn't end with just the types of endpoints supported, which include thin clients, zero clients, PCs running a thin client, and PCs running a compatible browser. It also often has to support both connected and disconnected clients, as well as work with remote clients whose connection speeds and quality can vary greatly.