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On 02/05/2014 04:45 PM, Justin Santa Barbara wrote:
> Russell Bryant  wrote:
>> So, it seems that at the root of this, you're looking for a
>> cloud-compatible way for instances to message each other.
> 
> No: discovery of peers, not messaging.  After discovery, communication

I'm saying use messaging as the means to implement discovery.

> between nodes will then be done directly e.g. over TCP.  Examples of
> services that work using this model:  Elasticsearch, JBoss Data Grid,
> anything using JGroups, the next version of Zookeeper, etc.  The
> instances just need some way to find each other; a nice way to think
> of this is as a replacement for multicast-discovery on the cloud.
> 
> All these services then switch to direct messaging, because using an
> intermediate service introduces too much latency.
> 
> With this blueprint though, we could build and run a great backend for
> Marconi, using OOO.
> 
>> I really don't see the metadata API as the appropriate place for that.
> 
> But I presume you're OK with it for discovery? :-)
> 
>> How about using Marconi here?  If not, what's missing from Marconi's API
>> to solve your messaging use case to allow instances to discover each other?
> 
> Well, again: discovery, so Marconi isn't the natural fit it may at
> first appear.  Not sure if Marconi supports 'broadcast' queues (that
> would be the missing piece if it doesn't).  But, even if we could
> abuse a Marconi queue for this:
> 
> 1) Marconi isn't widely deployed

Yet.

I think we need to look to the future and decide on the right solution
to the problem.

> 2) There is no easy way for a node to discover Marconi, even if it was deployed.

That's what the Keystone service catalog is for.

> 3) There is no easy way for a node to authenticate to Marconi, even if
> we could discover it

huh?

The whole point of Marconi is to allow instances to have a messaging
service available to them to use.  Of course they can auth to it.

> 
> I absolutely think we should fix each of those obstacles, and I'm sure
> we will eventually.  But in the meantime, let's get this into
> Icehouse!

NACK.

-- 
Russell Bryant