openstack team mailing list archive

[Eric Day <eday@xxxxxxxxxxxx>]

I've summarized the original email and added more sections for review
and discussion here:

http://wiki.openstack.org/QueueService

In particular there are details on the various components of the
queue service, a draft at what the REST operations will look like,
and a couple brief examples.

Please let me know if any clarification is needed and I'll update
the wiki. Feedback and discussion on use cases and what you think
the service should look like is very appreciated.

Thanks,
-Eric

On Mon, Feb 14, 2011 at 09:51:42AM -0800, Eric Day wrote:
> Hi everyone,
> 
> When looking at other services to include as part of OpenStack, the
> first that comes to mind for many is a queue. A queue service can
> not only provide a useful public cloud service, but can also provide
> one of the building blocks for other services. I've been leading an
> effort to research and gather requirements for a queue service and
> I'd like to share the current state and get community feedback. I
> expect real development to begin very soon, and would also like to
> identify developers who will have time to dedicate to this project.
> 
> I'd like to note this is not an official OpenStack project yet. The
> intention is once we have the community support and a simple
> implementation, we will submit the project to the OpenStack Project
> Oversight Committee for approval.
> 
> The reason we are initiating our own project vs using an existing one
> is due to simplicity, modularity, and scale. Also, very few (if any)
> existing queue systems out there were built with multi-tenant cloud
> use cases in mind. Very few also have a simple and extensible REST
> API. There are possible solutions to build an AMQP based service,
> but AMQP brings complexity and a protocol not optimized for high
> latency and intermittent connectivity.
> 
> The primary goals of the queue service are:
> 
> * Simple - Think simple REST based queues for most use cases. Easy
>   to access and use from any language. It should not require much
>   setup, if any, before you can start pushing messages into it.
> 
> * Modular API - Initially we'll focus on a simple REST API,
>   but this will not in any way be a first-class API. It should be
>   possible to add other protocols (AMQP, protocol buffers, Gearman,
>   etc) for other use cases. Note that the internal service API will
>   not always provide a 1-1 mapping with the external API, so some
>   features with advanced protocols may be unavailable.
> 
> * Fast - Since this will act as a building block for other services
>   that my drive heavy throughput, performance will have a focus. This
>   mostly comes down to implementation language and how clients and
>   workers interact with the broker to reduce network chatter.
> 
> * Multi-tenant - Support multiple accounts for the service, and since
>   this will also be a public service for some deployments, protect
>   against potentially malicious users.
> 
> * Persistent - Allow messages to optionally be persistent. For
>   protocols that can support it, this can be an optional flag while
>   the message is submitted. The persistent storage should also be
>   modular so we can test various data stores and accommodate different
>   deployment options.
> 
> * Zones and locality awareness - As we've been discussing in other
>   threads, locality in cloud services is an important feature. When
>   dealing with where messages should be processed, we need to have
>   location awareness to process data where it exists to reduce network
>   overhead and processing time.
> 
> Before diving down into implementation details, I would like to hear
> what folks have to say about the initial requirements above. Once
> there is something along the lines of agreement, I'll be sending out
> other topics for discussion dealing with implementation.
> 
> I'm looking forward to your feedback. Thanks!
> 
> -Eric