After updating Nagios to 4.4.4 → many "defunct processes"

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christimpaler
Posts: 8
Joined: Wed Jan 09, 2013 1:38 am

After updating Nagios to 4.4.4 → many "defunct processes"

Post by christimpaler »

Hi folks,
after updating Nagios Core from 4.4.3 to 4.4.4 I observe an increasing number of "defunct processes" (zombies?).

Code: Select all

22331 ?        Z      0:00 [check_nrpe] <defunct>
22332 ?        Z      0:00 [check_ssh] <defunct>
22333 ?        Z      0:00 [check_nrpe] <defunct>
22348 ?        Z      0:00 [check_nrpe] <defunct>

[and so on]
Environment:
- Nagios Core 4.4.4
- Red Hat Enterprise Linux 7.7
- 300 monitored hosts
- 6500 monitored services

The system load has NOT increased.
When stopping Nagios Core (systemctl stop nagios.service) all "zombie"-processes vanish immediately.

In the Nagios Release Notes (https://www.nagios.org/projects/nagios-core/history/4x/) I can find the following information:
Fixed defunct worker processes appearing after nagios was reloaded (#441, #620)
I wonder, if this "fix" has made things worse. This behaviour does not seem to be intended, right?
Does anyone here face the same issue?

Best Regards
C.I.
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swolf
Developer
Posts: 294
Joined: Tue Jun 06, 2017 9:48 am

Re: After updating Nagios to 4.4.4 → many "defunct processes

Post by swolf »

Hi @christimpaler,

We are aware of this issue. The defunct processes appearing here aren't related to the changelog line you mentioned, but rather a different change to the worker code related to gathering plugin output (issue #625).

In my testing so far, I haven't seen any obvious issues from the defunct processes. They are getting "cleaned" by the system within a minute or so of becoming defunct, and I haven't noticed any memory leaks occurring on the side of the nagios workers (which are their parent processes). Even so, we're working on a fix which should go out with 4.4.5.

Thanks,
Sebastian Wolf
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christimpaler
Posts: 8
Joined: Wed Jan 09, 2013 1:38 am

Re: After updating Nagios to 4.4.4 → many "defunct processes

Post by christimpaler »

Hello Sebastian,
that's the answer I was hoping for.
I can confirm there is no performance impact on the system.
Topic can be closed.
Thank you.
C.I.
scottwilkerson
DevOps Engineer
Posts: 19396
Joined: Tue Nov 15, 2011 3:11 pm
Location: Nagios Enterprises
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Re: After updating Nagios to 4.4.4 → many "defunct processes

Post by scottwilkerson »

christimpaler wrote:Hello Sebastian,
that's the answer I was hoping for.
I can confirm there is no performance impact on the system.
Topic can be closed.
Thank you.
C.I.
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