Re: [ecf-dev] zookeeper discovery comes and goes

[ahmed.aadel@xxxxxxxxxxxxxxxxxx]

Hi,

A service  is signaled as undiscovered
either because it is indeed unpublished from the other end point (nothing
new) ,  the connection is lost or session expired. These are  dealt
with in NodeReader.process(WatchedEvent
event),  this is
the closest point to the underlying zookeeper that get informed that a
data node is deleted or no more reachable, so I'd say debug that short
method to see wether it is a genuine serivce undiscovery or one masking
a session/connection loss. The recieved event is intuitive and should be
strighforward.
 A word about the session  mentioned
above:   a  client should send heart beats within a session-timeout
interval (currently set to 3000) to be considered still alive. 

best regards,
ahmed

From:	Wim Jongman <wim.jongman@xxxxxxxxx>
To:	"Eclipse Communication Framework (ECF) developer mailing list." <ecf-dev@xxxxxxxxxxx>, ahmed.aadel@xxxxxxxxxxxxxxxxxx
Date:	13-10-2010 11:02
Subject:	Re: [ecf-dev] zookeeper discovery comes and goes

---

Hi Bryan,

AFAIK the discovery mechanism does not in itself guard
the connection and decides to drop it. It merely listens and propagates
service registrations/deregistrations to the distribution provider.

I would say this behavior should be seen with
other discovery mechanisms as well.

Ahmed can you think of reasons why this could happen?

Regards,

Wim 

On Tue, Oct 12, 2010 at 4:56 PM, Bryan Hunt <bhunt@xxxxxxx>
wrote:
I'm seeing a strange problem with zookeeper service discovery.
 I've been experimenting with YourKit and noticed a ConcurrentModificationException
as reported here: https://bugs.eclipse.org/bugs/show_bug.cgi?id=327170

When I went to capture a better stack trace, I noticed that when I remotely
connected with YourKit, the client reported zookeeper undiscovered one
of my 4 remote services.  When I disconnect and reconnect YourKit,
the client reports that zookeeper discovers 4 remote services.

This problem appears repeatable.  The client and all 4 remote services
are running on the same machine.  Each remote service is running in
it's own JVM.  Any ideas on what is going on, or suggestions for tracking
down the problem?  Is there by chance some sort of very short keepalive
that might be having problems if there were a network delay or thread delay
when YourKit connects to the client JVM?

Bryan
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