Transitioning from one virtualization environment to another is not typically an easy process. Among other requirements, customers need a way to migrate virtual machines from the various hypervisor technologies. With the DMTF standard Open Virtualization Format (OVF) gaining momentum, Citrix believes that format will become the primary container used to move virtual workloads between clouds. As detailed on this blog in past entries, Citrix remains the only vendor to implement the ability to import a wide variety of 3rd party OVF appliances.
Of course, not all virtualized legacy assets are in OVF format. This may be because the virtual systems were created before OVF support was made available, or it may be because the cloud vendor doesn’t yet support OVF at all. Some legacy assets may not be virtualized at all. The output of many physical to virtual (P2V) conversion tools are one these standalone disk formats.
Bridging from the past to more modern virtualizaiton technologies, XenCenter 5.6 supports import of standalone disk images. Three formats are supported:
- VMDK – this is the VMware disk image format. The disk needs to have been properly exported from the VMware environment. Once that requirement is met, the Citrix VMDK import supports the same fix-up processing to enable the correct drivers.
- VHD – this is the disk format most widely supported by Microsoft. Driver fix-ups are also supported for this format.
- WIM- this format is the output of the sysprep process used to make a Windows disk image hardware-agnostic. Many enterprise customers use this to manage server and desktop images so they can be repeatably installed across many instances of a particular hardware configuration or even across hardware platforms. On XenCenter import, the XenServer drivers are placed into the file structure so they can be used on first boot.
As one example, the VMDK support makes possible a full transition from a VMware-based virtualization stack to a XenServer environment. A new XenServer customer need not upgrade to more recent VMware versions or build OVF containers where none existed before.
Here is a demonstration of this feature in action courtesy of Brian Ehlert from Citrix Labs. If you have additional ideas or requests for features such as new formats to support, let us know in the comments.