Sources of New Virtual Machines
Applies To: Virtual Machine Manager 2008, Virtual Machine Manager 2008 R2, Virtual Machine Manager 2008 R2 SP1
In Virtual Machine Manager (VMM), you can create new virtual machines from any of the following sources:
Existing virtual hard disks (VHDs)
Blank virtual hard disks
Existing virtual machines
Hyper-V virtual machines
Virtual Server virtual machines
VMware virtual machines
Existing physical computers
The following illustration shows the sources of new virtual machines.
Choosing a Virtual Machine Source
Your choice of virtual machine sources will depend largely on your needs and existing infrastructure.
When to use: When you have a library of VHDs that you want to leverage in your VMM environment. You would also choose existing VHDs when deploying any operating system from which VMM cannot create a template, such as a non-Windows operating system.
Discussion: You can use the New Virtual Machine action to create a virtual machine from an existing VHD. VMM will create a copy of the source VHD so that the original VHD is not moved or modified. The Administrator password on the VHD should be blank as part of the Sysprep process.
You can also create a template from the VHD and then create the new virtual machine from the template. For more information, see Creating Virtual Machines from a Template. Many customers maintain a library of sysprepped VHDs that they use repeatedly to create virtual machines. For more information, see How to Create a Virtual Machine from an Existing Virtual Hard Disk (http://go.microsoft.com/fwlink/?LinkID=162951).
Limitations: When creating a new virtual machine directly from an existing VHD, you cannot specify operating system configuration information (sysprep settings). To specify sysprep settings, create a template and then create the new virtual machine based on that template.
When to use: When you do not have pre-existing virtual machines or VHDs or when you want to create a virtual machine from scratch.
Discussion: You can use a blank VHD when you want to use an operating system with a Preboot eXecution Environment (PXE) or place an ISO image on a virtual DVD-ROM and install from scratch. This is an effective way to build a source image for a template. Configure the virtual machine so that you can install an operating system from a system CD, from an ISO image file in the library, or through a network service boot. You can attach an ISO image from the library to a virtual machine’s virtual DVD-ROM and then use the library copy rather than copying it local to the virtual machine. This saves from proliferating hundreds of ISO images with identical content over your environment and sharing the central library copy instead. For more information, see How to Create a Virtual Machine with a Blank Virtual Hard Disk (http://go.microsoft.com/fwlink/?LinkID=162952).
Limitations: Creating a virtual machine from scratch is labor-intensive and is usually unnecessary if you have established a collection of templates.
Existing Hyper-V or Virtual Server Virtual Machine
When to use: When you want to create a clone of a virtual machine for testing or when you want to keep a copy of a virtual machine in the Library for quick recovery.
Discussion: If you want to deploy a virtual machine stored in the library rather than a copy of the virtual machine, you can go to the library, select the virtual machine and click Deploy, which will move the virtual machine from the library to a managed host. For more information, see How to Deploy a Virtual Machine. You can also create a template from the existing virtual machine and create new virtual machines from the template. Creating a template can destroy the virtual machine that is used as the template's source because Sysprep strips the virtual machine of its computer identity. If you want to continue to use the source virtual machine after creating the template, you must clone the virtual machine before you start. For more information, see How to Clone a Virtual Machine (http://go.microsoft.com/fwlink/?LinkID=162902).
Limitations: When cloning a virtual machine, you cannot make changes to the operating system settings, but you can make changes to the hardware profile. Any virtual machine that you choose to clone cannot be running. It must be stopped or stored in the VMM Library.
Existing VMware Virtual Machine
When to use: When you have VMware virtual machines that you would like to move to Hyper-V. You might do this to free up resources on your ESX servers.
Discussion: VMM allows you to copy existing VMware virtual machines and create Hyper-V or Virtual Server virtual machines. Although we call V2V a conversion, V2V is a read-only operation that does not delete or affect the original source virtual machine. You can copy VMware virtual machines that are on an ESX host, in the VMM Library, or on a Windows share. The resulting virtual machine matches VMware virtual machine properties, including name, description, memory, disk-to-bus assignment, CD and DVD settings, network adapter settings, and parameters. For more information on V2V conversions, see V2V: Converting Virtual Machines in VMM.
Limitations: With a V2V conversion, you cannot make changes to the operating system settings.
Existing Physical Computer
When to use: When you have underutilized servers that you would like to consolidate. Also, when you want to move physical computers to virtual machines but want to avoid rebuilding the operating system and reinstalling applications.
Discussion: VMM allows you to convert existing physical computers into virtual machines through a process known as physical-to-virtual (P2V) conversion. VMM simplifies P2V by providing a task-based wizard to automate much of the conversion process. The new virtual machine has the same computer identity as the physical computer on which it is based. Since the P2V process is completely scriptable, you can initiate large-scale P2V conversions through the Windows PowerShell command line. For more information on P2V conversions, see P2V: Converting Physical Computers to Virtual Machines in VMM.
Limitations: You cannot perform a P2V conversion on a server running a non-Windows operating system.
When to use: When you have prepared a virtual machine with applications and agents and now want to deploy multiple unique virtual machines based on that original. Using templates to create new virtual machines is a best practice in VMM.
Optionally, you can create a template with no operating system profile. This template will not be customized and must be set up manually by the user.
You can use templates to create new virtual machines repeatedly with standardized hardware and software settings. In VMM, templates consist of: a hardware profile, a virtual hard disk, and a guest operating system profile. For more information on templates, see Creating Virtual Machines from a Template.
Limitations: If you create a new virtual machine from a template, you cannot store the virtual machine in the library but must place it on a host.