The OVF Virtualization Standard

For cloud computing to become a platform and technology independent offering the IT industry is adopting a number of interoperability standards. The key standard is the Open Virtualization Format (OVF) for packaging and distribution of virtual machines.  OVF offers the following:

Enables optimized distribution - OVF enables the portability and distribution of virtual appliances. In addition to support for compression for more efficient package transfers, OVF supports industry standard content verification and integrity checking, and provides a basic scheme for the management of software licensing.

Provides a simple, automated user experience – OVF offers a simple virtual machine installation process. Meta-data in the OVF file can be used to validate the entire virtual package getting transferred and validates whether each virtual machine can be installed. Compatibility with the local virtual hardware will also be verified.

Supports both single and multi virtual machine configurations – Software developers can configure complex multi-tiered services consisting of multiple interdependent virtual appliances.

Enables portable VM packaging - OVF is virtualization platform independent, while also enabling platform-specific enhancements to be captured. It supports the full range of virtual hard disk formats used for virtual machines, and is extensible to deal with future formats that are developed.

Affords vendor and platform independence - OVF does not rely on the use of a specific host platform, virtualization platform, or guest operating system.

Supports localization – OVF supports user visible descriptions in multiple locales, and supports localization of the interactive processes during installation of an appliance.

The OVF standard is not tied to any particular hypervisor or processor architecture. The proposal has been submitted to the Distributed Management Task Force (DMTF). OVF is endorsed by Dell,  HP, IBM, Microsoft, VMware and XenSource.

There is also the Virtual Machine Disk (VMDK) standard for the transfer of virtual disks. VMDK encodes only a single virtual disk from a virtual machine. A VMDK does not contain information about the virtual hardware of a machine, such as the CPU, memory, disk, and network information.

This text was extracted largely from http://www.vmware.com/appliances/getting-started/learn/ovf.html

Summary


Cloud offerings must be interoperable to offer hybrid solutions in which private as well as public clouds can offer a variety of services. OVF makes that feasible.