Changing the IP or a SOLR or Zookeeper host

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Changing the IP or a SOLR or Zookeeper host

dshih
If a SOLR or Zookeeper host is replaced such that the hostname comes back but
it now resolves to a different IP, are SOLR nodes and SOLRJ clients expected
to just continue working?  

I know that in this case replicas need to be re-created (and stale ones
deleted).  But I'm wondering if SOLRJ clients and/or other SOLR nodes need
to be restarted to pick up the hostname->IP change.



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Re: Changing the IP or a SOLR or Zookeeper host

Houston Putman
If you are changing the IP of a host running Zookeeper, it can be an issue.
It depends on the version of zookeeper that you are using. There was an
issue with ZK not re-resolving IP addresses on connection errors, but it
was fixed in 3.4.13 (
https://issues.apache.org/jira/plugins/servlet/mobile#issue/ZOOKEEPER-2184
). If you are using 3.5.x, you should be safe as the fix was made there as
well.

You should be fine doing this for Solr nodes, but Java has weird default
settings for caching DNS, where it can cache a DNS resolution infinitely
and never refresh it. Therefore I'd say you're safest if you do a rolling
restart of your cluster, and any clients using solrJ. (Unless you make sure
that you have the correct Java DNS cache settings)

On Tue, Nov 19, 2019, 2:52 PM dshih <[hidden email]> wrote:

> If a SOLR or Zookeeper host is replaced such that the hostname comes back
> but
> it now resolves to a different IP, are SOLR nodes and SOLRJ clients
> expected
> to just continue working?
>
> I know that in this case replicas need to be re-created (and stale ones
> deleted).  But I'm wondering if SOLRJ clients and/or other SOLR nodes need
> to be restarted to pick up the hostname->IP change.
>
>
>
> --
> Sent from: https://lucene.472066.n3.nabble.com/Solr-User-f472068.html
>