Parasitic characters in output

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StefThomas
Posts: 3
Joined: Wed May 31, 2023 8:35 am

Parasitic characters in output

Post by StefThomas »

Hi,

This problem happens randomly after the agent restarts, with any plugin. For example, it can trigger a false warning about two processes being present, while only one is. When this happens, I notice parasitic characters in the output, as in the example below:

Code: Select all

PROCS WARNING: 2 processes with regex args 'standalone' | procs=2;$▒2V$;1:2;0;
Restarting the agent always resolves the issue, but it’s still annoying as it leads to false alerts.

It happens with version 4.0.3 (on RHEL 7) as with 4.1.0 (on RHEL 8)

I activated the debug mode on one of our server and I’m waiting the problem to happen again on this particular server, but it didn’t yet.

A Github issue has been opened in October 2022 for this bug but hasn’t received any answer so far : https://github.com/NagiosEnterprises/nrpe/issues/269

I’m posting this here hoping it may have more attention.

Regards.
kg2857
Posts: 233
Joined: Wed Apr 12, 2023 5:48 pm

Re: Parasitic characters in output

Post by kg2857 »

What is the problem you're trying to resolve? What are the symptoms?
Since the word parasitic is meaningless in this context, I'll guess you mean the strange character in the perfdata output.
If restarting the agent resolves the issue maybe share what agent you use.
StefThomas
Posts: 3
Joined: Wed May 31, 2023 8:35 am

Re: Parasitic characters in output

Post by StefThomas »

Hi,

Thx for your quick answer and also to tell me that “parasitic” is wrong in this context. English isn’t my first language (I’m French). I should’ve checked before using this word.

Yes I’m talking about the strange character in the perfdata.

The agent is the NRPE agent supplied by Redhat in RHEL 7 or 8 (we got the bug with both versions). It’s version 4.0.3 for RHEL 7 and 4.1.0 for RHEL 8 (8.7) arch is x86_64.

This is a bug that is hard to troubleshoot, because it happens only sporadically. :( But I wondered if some developers may have a hint on what could cause that kind of bug.

Another information I forgot to tell : when I said it happens “randomly after the agent restarts”, it’s precisely when the agent starts after an OS reboot.
kg2857
Posts: 233
Joined: Wed Apr 12, 2023 5:48 pm

Re: Parasitic characters in output

Post by kg2857 »

Sorry if I grumped about the parasitic bit.
If you have a link to earlier issues feel free to share it.
Again, what problem does this create? I've never seen is so maybe it exists but I, and many others don't know about it.
Are you installing nrpe via an rpm or compiling? The nagios folks seem to prefer a manual install. I have no idea if one is better. I always install via a compile.
It's a bit of a confusing problem and I've never noticed it (maybe I need to). I'm also not sure how to localize it to a service and it seems to be nrpe. Grr.
StefThomas
Posts: 3
Joined: Wed May 31, 2023 8:35 am

Re: Parasitic characters in output

Post by StefThomas »

Hi,

The problem is that it creates an unknown status for all checks which rely on this agent.

We use the the binary RPM supplied by RedHat. If nobody ever had this strange behavior it may be caused by a particular configuration we have. And it may be a ton of things then…

If I have the “luck” it happens again on the servers on which I set the NRPE agent on debug mode, and if I have any clue, I’ll let you know.

I’ll probably propose the following workaround to my manager : systematically do a restart of the agent a few seconds after the os rebooted. Or maybe we will deploy a more version (compiled), but it’s a lot of work, and the fact that the bug happens randomly and rarely makes the validation of the solution difficult, if not impossible.

Thx for you time.
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