Upgrade controllers with no API downtime

Registered by Armando Migliaccio on 2016-06-30

Currently pretty much every major upgrade requires full shutdown for all neutron-server instances for the time while upgrade process is running. The downtime is due to the need to run alembic scripts that modify schema and transform data. Neutron-server instances are currently not resilient to working with older schema. We also don't make an effort to avoid 'contract' migrations.

The goal of the RFE is to allow upgrading controller services one by one, without full shutdown for all of them in an HA setup. This will allow to avoid public shutdown for API for rolling upgrades.

Blueprint information

Status:
Started
Approver:
Rossella Sblendido
Priority:
High
Drafter:
None
Direction:
Approved
Assignee:
None
Definition:
Approved
Series goal:
Accepted for queens
Implementation:
Slow progress
Milestone target:
milestone icon pike-2
Started by
Armando Migliaccio on 2016-11-01

Related branches

Sprints

Whiteboard

Oct-31-2016(armax): to agressively accelerate as soon as ovo effort completes.

Sep-08-2016(armax): deferred to Ocata

Aug-08-2016(armax): dependent effort progressing. This is a multi-cycle effort.

This is waiting for https://blueprints.launchpad.net/neutron/+spec/adopt-oslo-versioned-objects-for-db, should probably even bumped out of N right away.

Gerrit topic: https://review.openstack.org/#q,topic:bp/online-upgrades,n,z

Addressed by: https://review.openstack.org/386685
    Plan to support no-downtime upgrade for neutron-server

Addressed by: https://review.openstack.org/400239
    Forbid contract migration scripts for Ocata

(?)

Work Items

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