Please note: This schedule is for OpenStack Active Technical Contributors participating in the Icehouse Design Summit sessions in Hong Kong. These are working sessions to determine the roadmap of the Icehouse release and make decisions across the project. To see the full OpenStack Summit schedule, including presentations, panels and workshops, go to http://openstacksummitnovember2013.sched.org.
Registering this as a Nova session, but it really applies much more broadly.
I'd like to discuss adding an alternative db backend to Nova/Glance/Keystone/etc..
SQLAlchemy offers a diverse set of backends like MySQL, PostgreSQL, sqlite, etc, but none of those meet the needs of a system like OpenStack.
OpenStack needs a horizontally scalable, reliable, failure tolerant data store.
Amazon's seminal Dynamo paper is an inspiration in this space and is the basis for Riak and Cassandra which both seem like very likely backend candidates for this work.
I'd like to suggest using a somewhat backend agnostic approach, so instead of using Riak or Cassandra directly, we could target a well-known API such as AWS SimpleDB or DynamoDB. Client libraries already exist, the data store already exists (in the shape of AWS's own implementations), and its behaviour is well defined and well understood and it's known to scale.
BasicDB, an implementation of Amazon's SimpleDB, recently saw the light of day and a DynamoDB implementation might follow in its tracks, so there's a path towards an entirely free deployment, but the consumer side doesn't need to wait for the server to exist before getting started.
