Open Stack

This thread is shifting a bit...

I'd like to throw in another related idea we're talking about it...

There is storing data in key/value stores and there is also storing data in document stores.

Kubernetes uses a key/value store and builds a document store out of it. All its api then runs through a document store, not a key/value store.

This model has proven to be quite powerful. I wonder if an abstraction over document stores would be useful? wrapping around k8s crds would be interesting. A lightweight openstack without mysql would have some interesting benifits.

Thanks,
Kevin
________________________________________
From: Bogdan Dobrelya [bdobreli at redhat.com]
Sent: Tuesday, December 04, 2018 6:29 AM
To: openstack-discuss at lists.openstack.org
Subject: Re: [all][FEMDC] Etcd as DLM

On 12/4/18 2:15 PM, Thierry Carrez wrote:
> Not sure that is what you're looking for, but the concept of an oslo.db
> interface to a key-value store was explored by a research team and the
> FEMDC WG (Fog/Edge/Massively-distributed Clouds), in the context of
> distributing Nova data around. Their ROME oslo.db driver PoC was using
> Redis, but I think it could be adapted to use etcd quite easily.
>
> Some pointers:
>
> https://github.com/beyondtheclouds/rome
>
> https://www.openstack.org/videos/austin-2016/a-ring-to-rule-them-all-revising-openstack-internals-to-operate-massively-distributed-clouds

That's interesting, thank you! I'd like to remind though that Edge/Fog
cases assume high latency, which is not the best fit for strongly
consistent oslo.db data backends, like Etcd or Galera. Technically, it
had been proved in the past a few years that only causal consistency,
which is like eventual consistency but works much better for end users
[0], is a way to go for Edge clouds. Except that there is *yet* a decent
implementation exists of a causal consistent KVS!

So my take is, if we'd ever want to redesign ORM transactions et al to
CAS operations and KVS, it should be done not for Etcd in mind, but a
future causal consistent solution.

[0]
https://www.usenix.org/system/files/login/articles/08_lloyd_41-43_online.pdf

--
Best regards,
Bogdan Dobrelya,
Irc #bogdando