There's no denying that virtual appliances are a boon to the enterprise. You get all the advantages of a specialized application environment without the hardware-related costs (power consumption, management) that come with a typical hardware appliance. If only operating-system vendors could see the light.
Instead, we have Microsoft, which has the good sense to license its Virtual Hard Drive to run on something other than Virtual Server, but then sics its anti-virus tools to de-activate it whenever it does so. While this may cause some users to stay within the Microsoft fold, we suspect it will cause countless others to skip Redmond altogether and side with VMware or some other open-systems vendor.
We're already starting to see this schism taking place. A Swiss startup called Dunes, for example, recently released the Virtual Service Orchestrator, a sort of virtual appliance automation framework, under the Linux OS. This gives it instant compatibility with VMware, but Microsoft users will have to wait while "development is proceeding towards compatibility with all virtualized platforms, including Microsoft," in the words of a company press release.
Some vendors are working around these licensing issues through file-sharing and data migration tools, although these add another layer on what is supposed to be a simple software environment. XenSource recently launched, for free, the Virtual Disk Migration Tool that lets you convert VMs created under VMware of Microsoft Virtual PC or Virtual Server to the Xen Virtual Appliance format. From there, you can easily import them into XenEnterprise, XenServer or Xen Express as XenServer HVM guests. If you're into downloading various virtual appliances, or need to access a VM from another enterprise, this tool should help.
But it's not just market leaders dealing with proprietary platforms. A California firm called Untangle is making a name for itself with the open-source Untangle Gateway Platform as a counter to providers such as SonicWall, Barracuda and WatchGuard. The company's free downloadable appliance can be set up in less than an hour and features more than 30 open-source tools for network access and protection.
I guess it's no surprise that the virtual appliance market should run into the same licensing and use restrictions that plague all other aspects of enterprise networking. I'm sure the vendors pay a lot of money to work out the cost/benefits of open vs. closed systems, but it would be nice if they could figure out how to compete through innovation, service and performance, rather than by keeping their customers in cages.