Open Stack

Greetings,

One of the features we had on the roadmap for Grizzly was the ability to
backport DB migrations to stable/grizzly after the release if necessary.
 The blueprint became a Havana blueprint, because the implementation
turned out to just reserve a range of migrations numbers at the
beginning of Havana development.

    https://blueprints.launchpad.net/nova/+spec/backportable-db-migrations
    https://review.openstack.org/#/c/23759/

I wanted to make sure everyone was aware of this when doing reviews of
future db migrations.  It means that we must make sure that migrations
added for Havana are idempotent.  That way it should be safe to backport
them.  When someone upgrades from a stable release that included
backportable migrations, they're going to get the same migration again
at a higher number.

Thanks!

-- 
Russell Bryant