warning at solr startup on Ubuntu

[Szűcs Roland <sz...@bookandwalk.hu>]

Dear SOLR users,

I use Solr 9.0, with open jdk 11. After installation, I managed to access
the admin page of the solr, but I always get two warnings at the startup of
the server.

One is complaining about low entropy and the other is the max number of
open files.

Is there a blog post or any guidance how to get rid of this warning message
on Ubuntu 22.04?

Thanks,
Roland

Re: warning at solr startup on Ubuntu

[Shawn Heisey <ap...@elyograg.org>]

On 11/15/22 05:08, Szűcs Roland wrote:
> Dear SOLR users,
>
> I use Solr 9.0, with open jdk 11. After installation, I managed to access
> the admin page of the solr, but I always get two warnings at the startup of
> the server.
>
> One is complaining about low entropy and the other is the max number of
> open files.
>
> Is there a blog post or any guidance how to get rid of this warning message
> on Ubuntu 22.04?

The low entropy one might be solved by installing the "haveged" package 
with apt.  Some servers have hardware random number generators that 
Linux can use.  That is common on Dell servers, not sure about other 
OEMs.  The fact that you have a low entropy warning probably means that 
your hardware does not have a random number generator.

If you don't want to actually increase the limits as Nicolae mentioned, 
the warning can be eliminated by adding SOLR_ULIMIT_CHECKS=false to the 
include script.  That will usually be /etc/default/solr.in.sh or 
bin/solr.in.sh.  It doesn't take a very big install for a Solr to blow 
through typical OS default limits, so if it were me, I would prefer to 
adjust the limits rather than turn off the warning.

Thanks,
Shawn

Re: warning at solr startup on Ubuntu

[Nicolae Vartolomei <ni...@sematext.com>]

Hello Roland,

For the file maximum number of files you have to modify the limits.conf. 
The settings should look like:

@<solr user> hard nofile 65535

@<solr user> soft nofile 65535

Thank you,


On 2022-11-15 2:08 PM, Szűcs Roland wrote:
> Dear SOLR users,
>
> I use Solr 9.0, with open jdk 11. After installation, I managed to access
> the admin page of the solr, but I always get two warnings at the startup of
> the server.
>
> One is complaining about low entropy and the other is the max number of
> open files.
>
> Is there a blog post or any guidance how to get rid of this warning message
> on Ubuntu 22.04?
>
> Thanks,
> Roland
>
-- 
Nicoale Vartolomei
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