StructuredStateManagement

Summary

Move away from ad-hoc states and state transitions to a more concrete organized structured state management in nova.

Requirements

https://etherpad.openstack.org/task-system

Discussions

https://etherpad.openstack.org/the-future-of-orch

Plan of record

1. Create prototype.
2. Get feedback from summit session.
3. Get more feedback from email list & heat folks about common library.
4. Adjust prototype as needed from feedback.
5. Split prototype into small chunks.
6. Adjust tests for each small chunks.
7. Start to submit prototype chunks into review.openstack.org (disabling whole component until ready to turn on).

Design

High availability

In order to achieve high availability of this new orchestration layer the following key concepts must be build into the design the start.

1. A set of atomic tasks that can be organized into a workflow.
2. Task resumption and rollback.
3. Task tracking.
4. Resource locking.
5. Workflow sharding.
6. Simplicity (allowing for extension and verifiability).