In a dynamic VDI scenario, admins can set up virtualized applications to be delivered to virtual machines at runtime, rather than adding those apps to the master image cloned by VMs. This reduces the footprint of desktop virtual machines and simplifies application management. If you add application streaming technology, virtualized applications appear to start up faster, as if they were installed in the VM all along.
9. Client hypervisors will let you run virtual machines offline
A client hypervisor installs on an ordinary desktop or laptop so that you can run a "business VM" containing your OS, apps, and personal configuration settings. Talk about full circle: Why would you want all that in a virtual machine instead of installed on the desktop itself? Two reasons: One, it's completely secure and separate from whatever else may be running on that desktop (such as a Trojan some clueless user accidentally downloaded) and two, you get all the virtualization management advantages, including VM snapshots, portability, easy recovery, and so on. Client hypervisors also make VDI more practical. You can run off with your business virtual machine on a laptop and compute without a connection; then when you connect to the network again, the client VM syncs with the server VM.
Client hypervisors point to a future where we bring our own computers to work and download or sync our business virtual machines to start the day. Actually, you could use any computer with a compatible client hypervisor, anywhere. The operative word is "future" -- although Citrix has released a "test kit" version of its client hypervisor, and VMware is expected to release its own early version soon, shipping versions will not arrive before 2011.
The long march to the server side
Meanwhile, a completely different form of server-based computing continues to gain traction: the variant of cloud computing known as SaaS (software as a service), where service providers maintain applications and user data and deliver everything through the browser. A prime example is Google's campaign for Google Docs, encouraging users to forget about upgrading to Office 2010 and adopt Google's suite of productivity apps instead. Plus, Google's Chrome OS promises to create entire desktop environments in the cloud that retain user personalization.
Very likely, no big winner will emerge in server-based computing. Old-style Terminal Services setups will continue to crank along for offices harboring users with narrow, simple needs. True desktop virtualization on the VDI model will make sense where security and manageability are paramount, such as widely distributed organizations that use lots of contractors. And where far-flung collaboration is key, SaaS will flourish, because anyone with a Web browser can join the party. Conventional desktops may never disappear, but one way or another, the old centralized model of computing is making a comeback.
Read more about virtualization in InfoWorld's Virtualization Channel.