Cloned from launchpad blueprint https://blueprints.launchpad.net/keystone/+spec/service-relationships.

Description:

A volume service may be associated with an explicit compute service. There is no way to explicitly indicate this relationship via the service catalog today. Type and names can be duplicated according to the contract and expanding a URL type for a relationship seems like over-kill. There needs to be a collection or grouping of services to indicate which ones play well with each other. 

Specification URL (additional information):

http://etherpad.openstack.org/FolsomKeystoneServiceRelationships