OpenStack Kilo Design Summit

Problem: What types of updates do we want to support? How can we achieve this?
Discussion:
Should we be looking at nova objects to handle rolling updates better? https://review.openstack.org/#/c/127532/2/specs/kilo/adopt-oslo-versionedobjects.rst
I have added a cross project topic also.

Versioning all-the-things (RPC, API)
(shardy) Not neccesarily saying I have answers to this or that I need to lead the session, but this has been playing on my mind lately..

So far we've taken a less than disciplined approach to versioning things:

- Adding stuff (and worse later having to remove or disable it) to ReST API endpoints without changing the API version, so the actual capabilities of a Heat endpoint are not easily discoverable for clients

- Changing RPC interfaces over time without ever bumping the RPC version, this causes major problems for those doing rolling live upgrades of multi-engine heat deployments for example.

- Also what about resource plugin interfaces, should these be versioned , as they're not tied to the template DSL version?