==================================== Online SQL schema migration examples ==================================== This document links to several examples implementing online SQL schema migrations to facilitate simultaneously running OpenStack services in different versions with the same DB schema. * Nova `data migration example <http://specs.openstack.org/openstack/nova-specs/specs/kilo/implemented/flavor-from-sysmeta-to-blob.html>`_ * Nova `data migration enforcement example <https://review.openstack.org/#/c/174480/15/nova/db/sqlalchemy/migrate_repo/versions/291_enforce_flavors_migrated.py>`_ of sqlalchemy migrate/deprecated scripts * Nova `flavor migration spec <http://specs.openstack.org/openstack/nova-specs/specs/kilo/implemented/flavor-from-sysmeta-to-blob.html>`_ example of data migrations in the object layer * Cinder `online schema upgrades spec <https://specs.openstack.org/openstack/cinder-specs/specs/mitaka/online-schema-upgrades.html>`_ example of migrating a column to a many-to-many relation table For documentation on how to make online migrations move on to :ref:`Database Schema Migrations <online-migration>`.