Open Stack

Thanks robert,

I've started to tweak https://review.openstack.org/#/c/209661/ with 
regard to the outcome of that (at least to cover the basics)... Should 
be finished up soon (I hope).

Robert Collins wrote:
> Hi, at the summit we had a big session on distributed lock managers (DLMs).
>
> I'd just like to highlight the conclusions we came to in the session (
>      https://etherpad.openstack.org/p/mitaka-cross-project-dlm
>      )
>
> Firstly OpenStack projects that want to use a DLM can make it a hard
> dependency. Previously we've had a unwritten policy that DLMs should
> be optional, which has led to us writing poor DLM-like things backed
> by databases :(. So this is a huge and important step forward in our
> architecture.
>
> As in our existing pattern of usage for database and message-queues,
> we'll use an oslo abstraction layer: tooz. This doesn't preclude a
> different answer in special cases - but they should be considered
> special and exception, not the general case.
>
> Based on the project requirements surfaced in the discussion, it seems
> likely that all of konsul, etc and zookeeper will be able to have
> suitable production ready drivers written for tooz. Specifically no
> project required a fair locking implementation in the DLM.
>
> After our experience with oslo.messaging however, we wanted to avoid
> the situation of having unmaintained drivers and no signalling to
> users about them.
>
> So, we resolved to adopt roughly the oslo.messaging requirements for
> drivers, with a couple of tweaks...
>
> Production drivers in-tree will need:
>   - two nominated developers responsible for it
>   - gating functional tests that use dsvm
> Test drivers in-tree will need:
>   - clear identification that the driver is a test driver - in the
> module name at minimum
>
> All hail our new abstraction overlords.
>
> -Rob
>