The concept behind migrating from Citrix XenServer to Microsoft Hyper-V is the same as it is for those moving off of VMware ESX: you need to recover your existing VM assets. The process itself, however, is actually much easier.
This is because XenServer machines can use the VHD virtual disk format. Some caveats still apply, however. For example:
XenServer VMs use paravirtualized drivers that are installed through the xs-tools.iso image file. These drivers must be removed once you generate a Hyper-V virtual machine. They must be kept within the VM during the conversion, however, otherwise the VM will not boot in Hyper-V.
The XenServer VM configuration file is not compatible with Microsoft Hyper-V. Therefore, you will need to generate a new virtual machine in Hyper-V.
To convert XenServer virtual machines, follow these steps:
Determine the format of the source disk. If it is in RAW format, it may be possible to use it as is, in a pass-through disk. If it's in a storage repository, then it may be possible to convert it to VHD format. You can also use the XenConvert utility to convert the drive to VHD format. Use the Physical-to-VHD conversion process in this utility.
Make sure the guest operating system is running a version of the OS that supports Integration Services or Components. If not, update it if possible.
Shut down the virtual machine and copy the disk -- VHD or RAW -- to a storage location accessible to Hyper-V.
Create a new machine in Hyper-V using the copied disk and make sure you assign the system disk to an IDE connection. Use a virtual disk if the disk is in VHD format. Use a pass-through disk if it is in RAW format.
Boot the virtual machine in Hyper-V. It will boot to a working state because of the compatibility of the XenServer Tools. Log into the VM and install Integration Services or Components depending on the operating system being used.
Reboot the virtual machine and remove the XenServer Paravirtualization Tools. Reboot the VM again.
Log in and move to the Device Manager within the VM to make sure all of the devices work properly. If not, remove unnecessary devices and correct any issues that appear.
You can repeat this process for any other virtual machines that you want to move from XenServer to Hyper-V.
You can also use Citrix Project Kensho to convert virtual machines from Citrix to Hyper-V format. Project Kensho has actually been designed as a conversion tool for moving Open Virtualization Format (OVF) files to either Citrix XenServer or Microsoft Hyper-V formats and vice versa. The OVF format is an open standard format that captures all of the information about a virtual machine and converts it into a transportable format that can be imported into any hypervisor. OVF files include VM configuration files, virtual hard disks and any other files that make up the virtual machine. OVF contents are compressed for easier transportability.
Project Kensho examines the contents of the OVF and can then convert it to the appropriate file format for either XenServer or Hyper-V (see Figure 1). You should note that this conversion process does not include the installation of either the Integration Services for Hyper-V or the Paravirtualization Tools for XenServer. You will need to install them in the converted VM once it is running in the target hypervisor.
Once you complete these steps, your machine will be ready to run on Microsoft Hyper-V.
ABOUT THE AUTHORS
Danielle Ruest and Nelson Ruest are IT professionals focused on technology futures. Both are passionate about virtualization and continuous service availability. They are authors of multiple books, including MCITP Self-Paced Training Kit (Exam 70-652): Configuring Windows Server Virtualization with Hyper-V for MS Press as well as Virtualization, A Beginner's Guide and Windows Server 2008: The Complete Reference for McGraw-Hill Osborne. Feel free to contact them at firstname.lastname@example.org for any comments or suggestions.