This spec is a child spec of convergence. specs bp convergence-observer Change-Id: Id309bb1c847b976f0ba4a69ee99f3b3ed90ff356
1.7 KiB
Convergence Observer
https://blueprints.launchpad.net/heat/+spec/convergence-observer
As a step toward implementing the convergence
specification, Heat will split operations which fall into the "observing
reality" category into a separate "observer" process.
Problem description
External systems hosting the physical resources of a stack will change independent of operations in Heat. There is a need to have a way to record and respond to these changes.
Proposed change
Observer is responsible for managing the model of reality
- polls nova/neutron/etc using resource check methods.
- conceptually polls heat stack descriptions to update internal resources
Data model will need to store "observed state"
REST API will need to display "observed state"
Note that no change will be necessary to the resource plugin API. Also note that subscribing to notifications will be done in a separate blueprint named convergence-continuous-observer.
Alternatives
Implementation
Assignee(s)
Work should be spread between all developers as much as possible to help spread awareness of how things work.
Milestones
- Target Milestone for completion:
-
Juno-2
Work Items
- Modify data model to record resource state
- Modify public API to display observed state
- Create new observer RPC API calls
- Create new observer entry point
- Move "check_active" and "check" calls to use observer API