RV: Question about Zookeeper architecture

[DAVID MARTIN NIETO <dm...@viewnext.com>]

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David Martín Nieto
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De: DAVID MARTIN NIETO <dm...@viewnext.com>
Enviado: viernes, 29 de abril de 2022 10:17
Para: users@solr.apache.org <us...@solr.apache.org>
Asunto: RE: Question about Zookeeper architecture

Hi,

I make a similar question time ago and get this answer:

Shawn Heisey <ap...@elyograg.org>
Mié 24/02/2021 17:33
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Para:

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solr-user@lucene.apache.org

On 2/24/2021 9:04 AM, DAVID MARTIN NIETO wrote:
> If I'm not mistaken the number of zookeepers must be odd. Having 3 zoos on 3 different machines, if we temporarily lost one of the three machines, we would have only two running and it would be an even number.Would it be advisable in this case to raise a third party in one of the 2 active machines or with only two zookeepers there would be no blockages in their internal votes?

It does not HAVE to be an odd number.  But increasing the total by one
doesn't add any additional fault tolerance, and exposes an additional
point of failure.

But I have made test on preproduction environment and they are problems with only 2 zookeepers working, testing some HA fault tolerance test.

Can someone confirm that they must be odd for the issue of quorum in the voting.

On the other hand, I return to consult the same topic, there is some way to make the ips:ports of the connections to the zookeepers more dynamic? In case of crash of any machine where I host the zookeepers, I cannot raise an additional one with another ip:port, it is not added to the cluster directly, but I have to restart solr and modify yml of load batches in that solr.

Many thanks
Kind regards.

________________________________
David Martín Nieto

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De: matthew sporleder <ms...@gmail.com>
Enviado: jueves, 28 de abril de 2022 20:30
Para: users@solr.apache.org <us...@solr.apache.org>
Asunto: Re: Question about Zookeeper architecture

Ideally you should run zookeeper on three (small) different servers from
solr.

You should always have an odd number of zk servers so they can vote and not
tie.

On Thu, Apr 28, 2022 at 2:26 PM Heller, George A III CTR (USA)
<ge...@mail.mil.invalid> wrote:

> Hopefully this is the appropriate forum for a Zookeeper architecture
> question.
>
>
>
>
>
> I have two servers, a Primary server and a failover server. Right now my
> Zookeeper is on the primary server, so if it goes down Solr would not work.
>
>
>
> Should I have a zookeeper on both the primary servers? Should I have a
> third server created and put Zookeeper on the third server? What happens if
> the third server goes doen?
>
>
>
> Thanks,
>
> George
>