Integrating virtualization into the operating system is a bad idea. You're probably wondering why bundling more features into an OS isn't a good idea.

There are many reasons why bolting on a hypervisor to an OS is a bad idea.

First, it requires you to upgrade to the latest operating system version, such as the upcoming Linux OSes (Red Hat 5, SLES 10) to get virtualization capabilities. How long did your last operating system upgrade take? It also means that you have yet another operating system to manage per server. Who is going to pay for the additional calories and the redirection of scarce system administrator focus from more strategic activities that advance the business to patch management and other administrative tasks for these new operating system instances?