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

Mike Bayer mbayer at redhat.com
Fri May 19 21:31:16 UTC 2017

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".

Cockroachdb advertises SQLAlchemy compatibility very prominently.  While 
their tutorial at 
says it uses psycopg2 as the database driver, they have implemented 
their own "cockroachdb://" dialect on top of it, which likely smooths 
out the SQL dialect and connectivity quirks between real Postgresql and 

This is not the first "distributed database" to build on the Postgresql 
protocol, I did a bunch of work for a database that started out called 
"Akiban", then got merged to "FoundationDB", and then sadly was sucked 
into a black hole shaped like a huge Apple and the entire product and 
staff were gone forever.  CockroachDB seems to be filling in that same 
hole that I was hoping FoundationDB was going to do (until they fell 
into said hole).

> I'm welcome to being called mad, but I am curious if anyone has looked
> at this. I'm likely to do some tests at some stage regarding this,
> because I'm hoping this is the solution I've been hoping to find for
> quite a long time.

I'd have a blast if Keystone wanted to get into this.   Distributed / 
NewSQL is something I have a lot of optimism about.   Please keep me 
looped in.

> Further reading:
> https://www.cockroachlabs.com/
> https://github.com/cockroachdb/cockroach
> https://www.cockroachlabs.com/docs/build-a-python-app-with-cockroachdb-sqlalchemy.html
> Cheers,
> - Adrian Turjak
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