The homing service while determining the placements of the service, performs the match-making between the VNF's hardware requirements, and the hardware capabilities that are provided by the VIMs. These vendor requirements are captured as policies in the Policy framework and consumed by OOF to be used when determining the placements. Similarly, the hardware capabilities provided by the VIM instance (cloud-region) is exported to AAI by MultiCloud, and is consumed by OOF from AAI.
The proposal for persisting and retrieving HPA attributes related to a cloud-region from AAI can be found here: Persistence of HPA related information in AAI
Policy models required for HPA enablement in homing: