Virtualization Daily

Dan Farber from ZDNet has posted some interesting thoughts on the virtual appliance concept and how it fundamentally alters the role of the operating system.

The role of the OS in a virtual appliance becomes more about supporting applications. “In Windows and Linux, for example, the applications are coded to those APIs. Over time, there could be operating systems targeting different kinds of applications,” Rosenblum said. “Effectively if you look at reliability and security, you want to simplify, have an environment where can lop off everything not being used. When people start deploying OSs this way, such as for SAP or Oracle applications, you just want to have an OS that delivers what you need. With Linux and Windows you get the whole thing.”

Krishnamurti defined a virtual appliance as a preinstalled and preconfigured application packaged along with an OS in a virtual machine. “The role of an OS is changed. It just needs the interfaces for the applications running on top of it. As a result, OSs will get smaller and thinner. You pick an OS, fine tune it and package it up, and you don’t have to install fixes if they are not applicable. You could build an OS for supporting java virtual machines, and the customer wouldn’t know the difference, but it would be more secure and reliable.”

I’m not sure that we’ll necessarily see new operating systems crop up, but we will see a fundamental altering of the role of the operating system. Having access to an operating system that can be heavily customized is the critical element that’s required and we have that today with the free OS variants like Linux and FreeBSD. Those can be stripped down to a fairly small size and then heavily tuned for a particular application. As we gain more experience with this kind of thing we may even find the custom tuned appliance running on virtual infrastructure will outperform the equivalent application running on a generic OS directly on hardware. Given how much specialized expertise is required to tune an application once it’s installed this shouldn’t be a surprising thing at all. After all who is better equipped to tune the application than the people who wrote it. The tuning now moves to the virtualization layer which appears to reduce complexity, while dramatically increasing flexibility.