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Date: Tue, 12 Jan 2010 11:57:20 +0100
From: Sim IJskes - QCG <sim@qcg.nl>
Organization: Quality Consultancy Group b.v.
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To: river-dev@incubator.apache.org
Subject: Re: Lookup Service Discovery using DNS?
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Peter Firmstone wrote:
> Anyone got any opinions about Lookup Service Discovery?
> 
> How could lookup service discovery be extended to encompass the 
> internet?   Could we utilise DNS to return locations of Lookup Services?
> 
> For world wide lookup services, our current lookup service might return 
> a massive array with too many service matches. Queries present the 
> opportunity to reduce the size of returned results, however security 
> issues from code execution on the lookup service present problems.

I haven't seen any world wide deployments yet, at least not on my bench. 
:-) And i would like to reserve my definite judgement before i have had 
an actual production deployment of such a service.

As i understand it, reggie will replicate information between its peers. 
This unlimited replication needs to be controlled. Reggie is exposed as 
a JERI accesible service. So like any JERI service, access controls can 
be used to create islands. (I've not done this yet, but maybe others can 
confirm this.)

When we have several reggie islands running on the internet, it would be 
handy to find them via DNS SRV records.

But you are talking about MDNS SRV records. MDNS is a multicast protocol 
so it has the same pattern as the multicast discovery as currently 
implemented. In a broad sense one could suggest that this might suffer 
from the same deployment issues as een MDNS discovery would suffer. 
Except that MDNS is more mainstream and on more sites there might be a 
working infrastructure(substrate?) for it. (like MDNS holes in personal 
firewalls).

In any case the discovery is only part of the problem. The biggest 
problem seems to me how do you, as a jini client, talk to multiple 
reggies. I haven't solved this for now, but i have, in a production 
environment, reggie exported on a known endpoint, and allowing the 
clients to access reggie as a service, instead of running their own. 
This could be a construct that will allow for query-only worldwide reggies.

Gr. Sim

-- 
QCG, Software voor het MKB, 071-5890970, http://www.qcg.nl
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