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Zookeeper, mail # user - Question regarding ZK behaviour during leader reelection


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yuliya Feldman 2012-01-05, 22:30
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yuliya Feldman 2012-01-16, 18:28
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Camille Fournier 2012-01-16, 18:39
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Re: Question regarding ZK behaviour during leader reelection
yuliya Feldman 2012-01-16, 18:50
Thanks for quick answer.

I just wanted confirmation. I do handle it, just wanted to confirm that particular behaviour.

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 From: Camille Fournier <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]; yuliya Feldman <[EMAIL PROTECTED]>
Sent: Monday, January 16, 2012 10:39 AM
Subject: Re: Question regarding ZK behaviour during leader reelection
 
Yes your clients always need to handle state changes gracefully, and
absolutely, disconnect will happen when there is a change in leadership.

C

On Mon, Jan 16, 2012 at 1:28 PM, yuliya Feldman <[EMAIL PROTECTED]> wrote:

> Does not look like this question made to a forum.
> Resending it in hope that somebody from ZK developers will answer.
>
> Thanks.
>
>
>
> ________________________________
>  From: yuliya Feldman <[EMAIL PROTECTED]>
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Sent: Thursday, January 5, 2012 2:30 PM
> Subject: Question regarding ZK behaviour during leader reelection
>
> Hello here,
>
> I have a question regarding ZK clients behaviour during ZK Leader
> reelection.
>
> We have a situation where server where ZK Leader was running run low on
> memory and essentially ZK was "frozen" for quite a bit of time.
>
> Meanwhile other 2 ZK servers did reelections among them and new Leader was
> chosen.
>
> Now on ZK client nodes (not taking "bad" node into consideration) got
> Disconnect and Closely after Connect events, because as far as I understand
> no leader was available for about 500 ms. (during reelection).
>
> The question really is - as it is very likely that it will be some time
> during ZK leader election when none of the ZK servers will be available ZK
> clients are very likely to "feel" that something happened on the ZK Server
> (Quorum side).
> Which means that ANY application that relies on Zookeeper has to at least
> handle Disconnect event gracefully.
>
> Are my assumptions correct?
>
> Thanks.
>