Difference between OVA and OVF formats

What is the difference between the two OVF and OVA export/download formats? Like me in the past, you may have asked yourself the same.

OVF standards were formed and submitted to the DMTF in 2007, an industry working group comprising 17 industry-leading technology companies. Both the OVF and the OVA formats are cross platform open standards for packaging and distributing virtual machines.

Both the OVF and OVA formats typically comprise of four files;

  1. The descriptor file (.ovf) – An  XML file which describes the packaged virtual machine. The file also has metadata included such as the name, hardware requirements, references to the other files in the package and descriptions.
  2. Virtual Machine Disk Files (.vmdk) – VMware products utilise a variant of the VMDK format that is designed for distribution and compressed.
  3. A Manifest File (.mf) – Used for integrity and contains the SHA1 digest of all files in the package (except for the .mf). This file is optional and not required.
  4. A Certificate File (.cert) – You may also have a .cert file with the .mf file for authenticity to allow the package author to be verified. This file is optional and not required.

The key difference between OVF and OVA formats is the end presentation;

  • OVF – Collection of items in a single folder that can be downloaded and are visible separately i.e 4 files.
  • OVA – A single file with all of the necessary information encapsulated inside of it. Stored in the archive (.tar) file format.

The real benefit of an OVA over the OVF is the ease of portability and sharing, both use the same amount of disk space. I prefer the single download OVA!