Open Stack

On 09/20/2014 10:17 AM, Geoff O'Callaghan wrote:
> Hi all,
> I'm just trying to understand the messaging strategy in openstack.    It
> seems we have at least 2 messaging layers.
> 
> Oslo.messaging and zaqar,  Can someone explain to me why there are
> two?    To quote from the zaqar faq :
> ---------
> How does Zaqar compare to oslo.messaging?
> 
> oslo.messsaging is an RPC library used throughout OpenStack to manage
> distributed commands by sending messages through different messaging
> layers. Oslo Messaging was originally developed as an abstraction over
> AMQP, but has since added support for ZeroMQ.
> 
> As opposed to Oslo Messaging, Zaqar is a messaging service for the over
> and under cloud. As a service, it is meant to be consumed by using
> libraries for different languages. Zaqar currently supports 1 protocol
> (HTTP) and sits on top of other existing technologies (MongoDB as of
> version 1.0).
> --------
> It seems to my casual view that we could have one and scale that and use
> it for SQS style messages, internal messaging (which could include
> logging) all managed by message schemas and QoS.  This would give a very
> robust and flexible system for endpoints to consume.
> 
> Is there a plan to consolidate?

Hi Geoff,

No, there's no plan to consolidate.

As mentioned in the FAQ, oslo.messaging is a messaging *library* whereas
Zaqar is a messaging *service*. Moreover, oslo messaging is highly tight
to AMQP semantics whereas Zaqar is not.

Note that I'm not saying this isn't technically possible, I'm saying
these 2 projects have different goals, visions and scope, hence they
weren't merged nor they will.

Cheers,
Flavio

-- 
@flaper87
Flavio Percoco