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From Patrick Hunt <ph...@apache.org>
Subject Re: Dynamic adding/removing ZK servers on client
Date Mon, 03 May 2010 18:51:41 GMT


On 05/03/2010 11:29 AM, Dave Wright wrote:
>>> Well, that just handles distribution of the list (which isn't really
>>> our problem), it doesn't help with restarting the ZK client when the
>>> list changes - it only pulls the list once, so you still have to
>>> completely shutdown and restart the ZK client.
>>>
>>
>> Well the old server is being shutdown right? If the client were connected to
>> that server this would force the client to reconnect to another server, what
>> I was suggesting is that the client would ping the "server lookup" service
>> as part of this. (so lookup on every disconnect say)
>
> Perhaps we should clarify what you mean by "client" (..would ping..).
> If you mean the ZK client library, then that would make sense - rather
> than use a static list of servers, each time it was disconnected it
> would refresh it's list and pick one.
> I took it to mean the client application (using the ZK library). The
> issue is that the client application has no way to tell the ZK client
> lib to use a different list of servers, other than a complete teardown
> of the ZK object&  session, which I'm trying to avoid.
>

Yes, that's what I meant - we could update the ZK client lib to do this. 
It would be invisible to the client application (your code) itself.

>>
>> Hasn't come up before, but yes I agree it's a useful feature.
>
> Ok, thanks. We don't have a specific ETA to implement it, I just
> wanted to explore the option a bit before we finalized some aspects of
> our design. Should we do the work I'll submit matches for the Java and
> C client.

That would be great.

Patrick


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