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

Sylvain Bauza sbauza at redhat.com
Fri Dec 5 20:52:23 UTC 2014

Le 05/12/2014 21:14, Matt Riedemann a écrit :
> On 12/5/2014 1:45 PM, Andrew Laski 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.
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> I don't have experience with Alembic but I'd think we should use 
> Alembic for the new database unless there is a compelling reason not 
> to. Maybe we need Mike Bayer (or other oslo.db people) to give us an 
> idea of what kinds of problems we might have with managing two 
> databases with two different migration schemes.
> But the last part you said is key for me, if we can abstract it well 
> then hopefully it's not very painful.

I had some experience with Alembic in a previous Stackforge project and 
I'm definitely +1 on using it for the Cells V2 database.

We can just provide a nova-manage cell-db service that would facade the 
migration backend, whatever it is.

More information about the OpenStack-dev mailing list