Right now, nova is storing flavor information in system_metadata (current details about Instance, potentially former details for resize rollback, and potentially new details for resizes in progress). I don't believe any extra_specs information is stored.
Using system_metadata for this is a bit fragile, doesn't allow us to do any indexing, and makes it difficult to add new features related to flavors.
(Some new features I'd like to see involve a concept of Flavor Groups, where you can assign flavors to group names. Quotas per flavor group, cells/aggregates naming supported flavor groups, and policies based on flavor groups are some ext.. and then apply policies based on the groups.)
We've planned to remove instance_type_id from Instance and strictly rely on system_metadata, but I think this may not be the right way to go. We do need to remove instance_type_id, but I'm thinking we may want a new table to store mappings of Instance -> Flavor information.
The purpose of this session is to come up with ideas on how we should store flavor information tied to instances, accounting for some future uses of flavors.
