Nagios Core - Failed to register iobroker

Problem Description

This KB article addresses the following errors you may see in the nagios.log file:

[1504231962] wproc: Core Worker 68003: Failed to register iobroker for stdout
[1504231962] wproc: Core Worker 68003: Failed to register iobroker for stderr
[1504231962] Warning:  Check of host 'SOME_HOST' did not exit properly!
[1504231962] HOST ALERT: SOME_HOST;UNREACHABLE;SOFT;1;(Host check did not exit properly)

Resolution

This problem can occur when custom operating system limits restrict the max number of processes that can be executed.

Custom limits are defined in the /etc/security/limits.conf file, here is an example of limits defined in openSUSE Leap 42.x:

# harden against fork-bombs
*               hard    nproc           1700
*               soft    nproc           1200
root            hard    nproc           3000
root            soft    nproc           1850

You will need to increase the hard and soft values to resolve the problems you are experiencing, for example:

# harden against fork-bombs
*               hard    nproc           10000
*               soft    nproc           10000
root            hard    nproc           10000
root            soft    nproc           10000

After making the changes it is recommended to reboot the operating system to ensure the limits are applied.

If the change does not fix the problem then you should increase the values again.

Final Thoughts

For any support related questions please visit the Nagios Support Forums at:

http://support.nagios.com/forum/