[openstack-dev] [Keystone] Cockroachdb for Keystone Multi-master

Thierry Carrez thierry at openstack.org
Mon May 22 09:02:21 UTC 2017

Mike Bayer wrote:
> On 05/18/2017 06:13 PM, Adrian Turjak wrote:
>> So, specifically in the realm of Keystone, since we are using sqlalchemy
>> we already have Postgresql support, and since Cockroachdb does talk
>> Postgres it shouldn't be too hard to back Keystone with it. At that
>> stage you have a Keystone DB that could be multi-region, multi-master,
>> consistent, and mostly impervious to disaster. Is that not the holy
>> grail for a service like Keystone? Combine that with fernet tokens and
>> suddenly Keystone becomes a service you can't really kill, and can
>> mostly forget about.
> So this is exhibit A for why I think keeping some level of "this might
> need to work on other databases" within a codebase is always a great
> idea even if you are not actively supporting other DBs at the moment.
> Even if Openstack dumped Postgresql completely, I'd not take the
> rudimental PG-related utilities out of oslo.db nor would I rename all
> the "mysql_XYZ" facilities to be "XYZ".
> [...]
Yes, that sounds like another reason why we'd not want to aggressively
contract to the MySQL family of databases. At the very least, before we
do that, we should experiment with CockroachDB and see how reasonable it
would be to use in an OpenStack context. It might (might) hit a sweet
spot between performance, durability, database decentralization and
keeping SQL advanced features -- I'd hate it if we discovered that too late.

Thierry Carrez (ttx)

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