Once you have updated the Windows Server 2008 operating system with the Hyper-V technology release bits and enabled the Hyper-V role, you are ready to run virtual machines (VMs) on your server, now called a virtualization server (also called a “host”).
How does this change your security? Not much. Hyper-V is designed to be fairly transparent. You secure your VMs the same way that you secure physical machines. For example, if you run antivirus software on the physical machine, run it on the VM (not the host). If you segment the physical server to a particular network, do the same to the VM.
Securing the virtualization server itself involves all the measures you take to safeguard any Windows Server 2008 server role, plus a few extra to help secure the VMs, configuration files, and data. For more information on helping to secure Windows Server 2008 workloads, see the “Windows Server 2008 Security Guide.”