Hyper-V Server 2012 is Microsoft's completely free type-1 hypervisor product.  Unlike some other competing free hypervisors, Hyper-V Server 2012 has the same virtualization scale and availability features as the Hyper-V role in licensed editions of Windows Server 2012, but it's optimized for running only the Hyper-V hypervisor on bare metal.  It's a great solution when you're looking to deploy dedicated hypervisor hosts within your shop.  The result?  An enterprise-scale type-1 hypervisor for FREE! You can get more details on Hyper-V Server 2012 here.

Recently, I was involved in a project that was migrating from Hyper-V Server 2008 R2 to Hyper-V Server 2012.  Due to architectural changes involved in implementing the new features in Hyper-V Server 2012, a direct in-place upgrade is not possible.  However, the across-the-wire migration process we used below was straight-forward and worked very well.  A ton of work has been done by the product team on improving the virtual machine export/import process, and we definitely saw this area shine during our project. Here's the migration steps we used:

Preparation Steps for New Target Hyper-V Server 2012

1. Install and configure a new Hyper-V Server 2012 box. 
   
2. Set up the same Virtual Networks as the source host in Hyper-V Manager using the "Virtual Switch Manager" host action.

Migration Steps for Existing Source Hyper-V Server 2008 R2

1. Backup the original source Hyper-V Server 2008 R2 server as a precaution.  We won't be making any changes to this box during the migration, but it never hurts to be safe! :-)
   
2. Shutdown running virtual machines on original source Hyper-V Server 2008 R2 server.
   
3. Review each virtual machine for snapshots - any snapshots taken of a running virtual machine should be merged by using the "Delete Snapshot ..." guest action in Hyper-V Manager.  Snapshots of running VM's are not supported for migration due to hardware and software architectural differences on the source and target servers.
   
4. Review each virtual machine and ensure that any Saved States are removed using the "Delete Saved State ..." guest action in Hyper-V Manager. Saved states of VM's are not supported for migration due to hardware and software architectural differences on the source and target servers.
   
   Important! If there are important changes saved in a VM's saved state that you wish to capture, start and gracefully shutdown the VM rather than simply deleting it's saved state.
   
5. Set the MAC address option in the settings of each VM to "Static" prior to migrating.  This allows the guest OS to maintain a fixed relationship between virtual NIC and MAC address even after migrating to the target Hyper-V Server 2012 server and prevents you from needing to potentially reconfigure virtual NICs post-migration.
   
6. Export each VM using the "Export ..." action in Hyper-V Manager to an external storage location or network location that is reachable from both the new target Hyper-V Server 2012 box and your remote administration PC.

Migration Steps for New Target Hyper-V Server 2012

1. Import each exported VM on the new target Hyper-V Server 2012 box using the "Import Virtual Machine ..." host action in Hyper-V Manager.
   
   Important! When using the new Import Virtual Machine wizard, you will be prompted to "Register", "Restore", or "Copy" the virtual machine when importing.  You will want to select the "Restore" option and confirm the path on the new Hyper-V host to which the VM will be restored.
   
2. Review the settings of each imported VM using the "Settings ..." guest action in Hyper-V Manager.  Hyper-V Server 2012 provides the ability to assign more virtual processors (up to 64 per VM), more virtual memory (up to 1TB per VM) and new virtual hardware options, such as Virtual Fiber Channel HBAs and network offloading/security.  For some VMs, you may wish to take advantage of these new capabilities by adding virtual hardware resources.
   
3. Start each VM using the "Start" guest action in Hyper-V Manager to confirm that the VM starts successfully.
   
4. Connect to the console of each VM using the "Connect ..." guest action in Hyper-V Manager to confirm successful guest OS boot.
   
5. Login at the console of each VM and confirm that all services have started
   
6. Update the Hyper-V Integration Services for each VM by using the "Action -> Insert Integration Services Setup Disk" option on the menu bar of each Virtual Machine Connection window.

Rinse and Repeat ...
If you have multiple Hyper-V Server 2008 R2 hosts that you are migrating, you can perform this same set of migration steps for each host - one at a time - and, after each host is migrated, rebuild the old source host as a new Hyper-V Server 2012 box for migrating the VMs from your next Hyper-V Server 2008 R2 machine.

What If I'm Migrating from VMware?
If you're migrating VM's from a VMware host, rather than using the middle set of migration steps for exporting VMs, you can instead use the new FREE Microsoft Virtual Machine Converter solution accelerator tool.  This tool provides a streamlined conversion process that accomplishes the following tasks in the migration process:

• Converts and deploys virtual machines from VMware hosts to Hyper-V hosts. As part of the machine conversion MVMC converts the virtual disks attached to the source virtual machine. It also migrates configuration such as memory, virtual processor and so on from the source virtual machine to the converted virtual machine deployed on Hyper-V. It adds virtual network interface cards (NICs) to the converted virtual machine on Hyper-V.
  
  • Supports conversion of virtual machines from VMware vSphere 4.1 and 5.0 hosts to Hyper-V.
    
  • Note: MVMC also supports conversion of virtual machines from VMware vSphere 4.0 if the host is managed by vCenter 4.1 or vCenter 5.0. You have to connect to vCenter 4.1 or 5.0 through MVMC to convert virtual machines on vSphere 4.0.
    
• Converts VMware virtual disks to Hyper-V based virtual hard disks (VHDs).
  
• Uninstalls VMware tools prior to conversion to provide a clean way to migrate VMware-based virtual machines to Hyper-V.
  
• Installs Hyper-V Integration Services on the converted virtual machine if the guest operating system is Windows Server 2003 SP2.
  
• Has a wizard-driven GUI, making it simple to perform virtual machine conversion.
  
• Offers fully scriptable command-line interfaces for performing virtual machine and disk conversions that integrates well with data center automation workflows and Windows PowerShell scripts.

Share Your Migration Tips!

These steps have worked well for me in migrating to Hyper-V Server 2012, but please feel free to share your migration tips in the comments below if you've migrated differently so that we can grow our set of migration "best practices" together.

Hope this helps!

Keith

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