Hyper-V Implementation Details

Microsoft Hyper-V hypervisor-based virtualization platform is a revolutionary step forward because it finally puts Microsoft's virtualization platform in the same ballpark as VMware's ESX Server. However, if you're familiar with Microsoft's previous virtualization product, Microsoft Virtual Server 2005, you might be surprised to see that almost all of the implementation details are different in Hyper-V. About the only thing that's consistent is the use of the Virtual Hard Disk (VHD) format. In this column, I take you on a guided tour through the details of Hyper-V's implementation.

1. Hyper-V installation—The first big difference between Hyper-V and Virtual Server 2005 is how the products are installed. Virtual Server 2005 is installed by running a setup program, but Hyper-V is installed either as a Windows Server 2008 role or as the standalone Hyper-V Server. In both cases, Hyper-V requires a 64-bit processor with either Intel VT or AMD-V support.

2. Hyper-V Manager—The next big difference that you notice is that the management tools have all changed. Virtual Server 2005 is managed through a web-based interface, but Hyper-V is managed using Hyper-V Manager, a Microsoft Management Console (MMC) snap-in that lets you perform all the basic virtual machine (VM) management tasks, such as creating, starting, and stopping VMs.

3. Default VM location—You might wonder where on the disk VMs go when you create them. By default, Hyper-V stores its VMs in the folder C:\ProgramData\Microsoft\Windows\Hyper-V\virtual machines. You can change the default location by right-clicking the Hyper-V host in Hyper-V Manager and selecting Hyper-V Settings.

4. Virtual Hard Disk—The VHD (.vhd) file is interchangeable between Virtual Server 2005 and Hyper-V. To import existing Virtual Server 2005 VMs into Hyper-V, you essentially create a new VM, then point it to the existing .vhd file.

5. Virtual machine configuration files—One of the key components of a VM is its virtual machine configuration file. Virtual Server 2005 stores VM configuration information in an easy-to-find-and-copy file and names it with the VM name plus the .vmc extension (e.g., MyVM.vmc). Following the unwritten law that all products must be needlessly more complex than their predecessors, Hyper-V stores the VM configuration information in the Virtual Machines folder using a file that's named with a globally unique identifier (GUID) and ends with the .xml extension (e.g., 00C5B017-B364-4F21-865A-28F47D8C530F.xml).

6. Snapshots—Like VMware's ESX Server, Microsoft's Hyper-V is able to take snapshots—saving the running VM state at a given point in time. Snapshots are named with a GUID and by default placed in a folder with the same GUID name; the GUID folder is in the Virtual Machines folder. Unlike configuration files, snapshot files have no file extension.

7. Integration components—Hyper-V's integration components are similar to Virtual Server 2005's Virtual Machine Additions. They're installed into a running VM, and they include the specialized drivers needed to take advantage of Hyper-V's high-performance VMBus architecture. You install integration components by using the Virtual Machine Connection and selecting the Action, Insert Integration Services Setup Disk option.

8. Virtual Network Manager—If you want your Hyper-V VMs to have any networking capabilities, you must run the Virtual Network Manager at least once. It lets you create external networks that connect to the host's NIC, internal networks that connect VM's and the physical host, and private networks that connect just VMs. You start the Virtual Network Manager from the Hyper-V Manager's Task pane.

9. Edit Virtual Hard Disk Wizard—The Edit Virtual Hard Disk Wizard is also started from the Hyper-V Manager's Task pane. It lets you compact a VMs VHD, convert between dynamic and fixed VHDs, and expand the size of an existing VHD.

10. Hyper-V services—Finally, under the covers there are three Hyper-V services that let you manage Hyper-V: the Hyper-V Image Management Service, the Hyper-V Networking Management Service, and the Hyper-V Virtual Machine Management Service. You control the Hyper-V services by using the Administrative Tools, Services menu option.