Importance of having the lsof utility on our solr server VMs

[THADC <ti...@gmail.com>]

Hello,

Today I am running the ./bin/solr command from new VMs that apparently don't
have the lsof command installed. I noticed a warning message saying the
command needs lsof in order to determine if solr is listening on the port I
am trying to have it run on. But then is says its started anyway.

I did a search on this archive and found thread that said as long as each
node is started separately, then you should be ok. We will probably always
be firing up the nodes individually anyway. So, can I safely assume we don't
need lsof?


Thanks!



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Re: Importance of having the lsof utility on our solr server VMs

[THADC <ti...@gmail.com>]

Thanks. I think that's a good point that it helps recognize port conflict at
start up. Although that scenario is unlikely in my case, I am going to try
to get it installed.



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Re: Importance of having the lsof utility on our solr server VMs

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

On 6/28/2018 11:22 AM, THADC wrote:
> Today I am running the ./bin/solr command from new VMs that apparently don't
> have the lsof command installed. I noticed a warning message saying the
> command needs lsof in order to determine if solr is listening on the port I
> am trying to have it run on. But then is says its started anyway.
>
> I did a search on this archive and found thread that said as long as each
> node is started separately, then you should be ok. We will probably always
> be firing up the nodes individually anyway. So, can I safely assume we don't
> need lsof?

If you can be absolutely certain when you ask for Solr to be started
that there is no possibility that something else is already listening on
the Solr port, then you probably don't actually need lsof.

If you do have lsof, and it finds something already listening on the
Solr port, then the script will exit, and it won't even try to start
Solr.  Without lsof, it cannot know whether the port is in use, so it
will start, but if the port is in use, Solr will not start properly.

Thanks,
Shawn