Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/ovf-metadata-image-property.
It's nova side support for glance "Enhanced Platform Awareness OVF Meta-Data Import in Glance" at https://review.openstack.org/#/c/104904/ .
OVF is one of the open standards that the NFV
Industry Specification Group (ISG) in the European Telecommunications 64
Standards Institute (ETSI) are considering as part of the interface between the
higher level orchestration layers and the virtualized infrastructure manager.
One thing for OVF metadata is, it provide capability requirement for the platform, and such requirement should be understood by nova, so that when spawning a VM, the VM will get the platform capabilities.
Specification URL (additional information):