With respect to your 2nd question (in case it didn't get answered) nothing 
happens to the ephemeral nodes. as long as the client is able to talk to any 
active server before the session timeout the ephemeral nodes will stay.

From: Nuthan Ashkore [nuthanashk...@yahoo.com]
Sent: Tuesday, January 06, 2009 1:00 AM
To: zookeeper-user@hadoop.apache.org
Subject: group messaging, empheral nodes on zookeeper

I've 2 separate questions regarding zookeeper:

1. Group Messaging:
Is it possible to do group messaging with zookeeper 3.0.1 ?
If not, are there any plans to add group messaging (say w/ casual ordering or 
even better total ordering) to future releases ?
What would be the best approach if I need to do group messaging using zookeeper 
right now, should I use a separate group messaging or messaging broker service ?

2. What happens to Empheral Nodes when a zookeeper server (not client) dies or 
is separated from the group ?

Supposing there are 5 zookeeper servers: server_1, ..., server_5
And a client c_1 connects to server_1 and creates an empheral node /nd_1

2a: What happens if server_1 dies/crashes (and c_1 is disconnected from 
server_1) ?
    Is /nd_1 automatically deleted ?

2b: What happens if server_1 is disconnected from the rest of the group 
(server_2 to
    server_5, but client c_1 still remains connected to server_1 ?
    Is /nd_1 automatically deleted ?
    What happens if server_1 regions the rest of the group ?
    what happens to /nd_1 then ?


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