All virtualization
products use their own formats for the virtual appliances due to
which virtual appliances created using a particular product can only
be used properly with that specific solution. This is not a happy
situation.
Open Standards to the rescue
A new development which promises to overcome this short coming is a new standard for packaging virtual machines- Open Virtualization Format (OVF) (http://www.vmware.com/appliances/learn/ovf.html)
It was perceived
by the Distributed Management Task Force (DMTF)
OVF, among other things will allow interoperability among the various virtualization products availalble.
Compared to VMDK or VDI which encloses only a single virtual disk in the virtual machine, the OVF format provides a complete specification of the virtual machine. This includes the full list of required virtual disks plus the required virtual hardware configuration, including CPU, memory, networking, and storage.
The OVF is a standards-based, portable format that allows the user to deploy this virtual machine in any hypervisor that supports OVF.
OVF makes heavy use of XML and the technical specifications are available at http://www.vmware.com/pdf/ovf_spec_draft.pdf
More information on OVF is available at http://www.vmware.com/appliances/learn/ovf.html
ovftool
The ovftool is a Java based experimental tool to convert VMs to and from OVF, and converting standard sparse/flat VMDK files to and from the compressed stream- optimized VMDK format used in OVFs. (VMDK is the file format used by VMWare for virtual disks)
It is available for download here at http://www.vmware.com/download/eula/ovf_eula.html
