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From "Bae, Jae Hyeon" <metac...@gmail.com>
Subject Re: Restarting leader zookeeper instance made quorum lost
Date Wed, 09 Apr 2014 19:56:00 GMT
Hi Ted

Let me clarify. a) is correct. There were normally running 5 instances with
3 as quorum. I restarted the leader instance and while re-electing leader,
zookeeper cluster lost quorum for a minute and a few zookeeper clients lost
connection. So, this is the form of losing quorum, correct?

Is there any way to avoid losing quorum while rolling restart of zookeeper
cluster, specifically the leader instance?

Thank you
Best, Jae


On Wed, Apr 9, 2014 at 12:06 PM, Ted Dunning <ted.dunning@gmail.com> wrote:

> Your email is a little ambiguous.
>
> a) "5 instances with 3 as quorum" could mean 5 instances configured and
> running normally.
>
> Or
>
> b) it could mean 5 instances with 2 instances that are down.
>
> In (a) restarting the leader instance *should* cause the cluster to do a
> leader election again and form a new quorum.  That is a form of losing
> quorum.  If that is what you mean, this is normal.  A new quorum should be
> formed and things should continue fairly soon.
>
> In (b), restarting the leader will result in only 2 instances running which
> is not enough to maintain quorum and until you have at least 3 nodes
> running again, you can't proceed.
>
>
>
>
>
>
> On Wed, Apr 9, 2014 at 11:03 AM, Bae, Jae Hyeon <metacret@gmail.com>
> wrote:
>
> > Hi zookeeper users
> >
> > While rolling restart zookeeper cluster of 5 instances with 3 as quorum,
> > restarting the leader instance made quorum lost. Is this expected?
> > Otherwise, how can I restart the leader instance without interrupting
> whole
> > cluster? Or is this fixed in 3.4.6?
> >
> > Thank you
> > Best, Jae
> >
>

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