[Vrs-development] Cluster Management Message (was CVS)

[Chris Smith]

On Monday 18 February 2002 14:34, Bill Lance wrote:

> I'm continuing to bore down on the Repository.  Does
> theCluster Management Message definition mesh with the
> Goldwater framework?

Okay I've printed the whole thing off and am going through with a highlighter 
pen!

It's interesting you should ask about the cluster management messages as I 
was having a real think about that this weekend.  I spend a day rationalising 
the admin side of Goldwater so that it's very much cleaner, and I found 
myself thinking about Domain support again.

I thought that a concept of 'anonymous' domains might be terribly useful - 
though there would have to be a cap on the number of anonymous domains a 
single domain may know about.  This means that inter LDS communication could 
be through Goldwater service calls, where each LDS is an anonymous domain.
Anonymous domains would only be able to 'see' goldwater services (or modules) 
that are tagged as 'anonymous'.

I quite like this idea - though I'm not sure how well it really does fit into 
the architecture... I'll do some more work on this.

This does mean resurrecting Phoenix (no pun intended!) for the network comms 
(far more efficient than something like Apache) - but we did say that we'd 
like to use a tight binary format, which precludes using port 80 anyway.

The coming and going of LDSs would then, if Domains were used, mean 
information added to Goldwater's domain tables AND the service discovery 
directory(s).

How this is done is another matter.  Though I'm thinking that Goldwater could 
have an 'add anonymous domain' internal service call which may be invoked by 
one of our service modules.  This LDS module also sends an update to the 
service discovery directory(s).  Knowledge of the new anonymous domain needs 
to be propagated around the domains that comprise the VRS - that'll be 
interesting.

Having two domains available means that you have two copies of all services 
that a domain exports (assuming they are identical domains - which they 
should be for LDSs).  Calling these services will result in any one of the 
available copies being invoked.  Referencing them by namespace will allow you 
to call a specific instance.  We thus use the namespace functionality to talk 
to specific LDSs through the same interface as all LDSs.

So it's kind of gone full circle.... and the rewrite of GW's Domains to 
handle namespacing has come straight back at me as a (potential) solution to 
LDS comms.  And I was going to leave that for a rainy day... Ho Hum.

I need to think about this MUCH more.

Chris
-- 
Chris Smith
  Technical Architect - netFluid Technology Limited.
  "Internet Technologies, Distributed Systems and Tuxedo Consultancy"
  E: address@hidden  W: http://www.nfluid.co.uk