[openstack-dev] [Nova] sqlalchemy-migrate vs alembic for new database

Johannes Erdfelt johannes at erdfelt.com
Fri Dec 5 20:42:11 UTC 2014

On Fri, Dec 05, 2014, Andrew Laski <andrew.laski at rackspace.com> wrote:
> The cells v2 effort is going to be introducing a new database into
> Nova.  This has been an opportunity to rethink and approach a few
> things differently, including how we should handle migrations. There
> have been discussions for a long time now about switching over to
> alembic for migrations so I want to ask, should we start using
> alembic from the start for this new database?
> The question was first raised by Dan Smith on
> https://review.openstack.org/#/c/135424/
> I do have some concern about having two databases managed in two
> different ways, but if the details are well hidden behind a
> nova-manage command I'm not sure it will actually matter in
> practice.

This would be a good time for people to review my proposed spec:


Not only does it help operators but it also helps developers since all
they would need to do in the future is update the model and DDL
statements are generated based on comparing the running schema with the

BTW, it uses Alembic under the hood for most of the heavy lifting.


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