icinga2_check_oom

Icinga2/Nagios check for Out of memory problems. ATM it check all dmesg output. If you want after check make it green again, you need to run dmesg -c.

About this fork

The original version of this check assumes that non-root users can run /bin/dmesg, which is true on Ubuntu but not Debian (and likely other distros). While you can give unprivileged users access to /bin/dmesg with sudo sysctl -w kernel.dmesg_restrict=1 (source), this has security implications. Instead, I've created a variant that uses a setuid wrapper, hard-coding the path to the original Nagios check to prohibit setuid abuse.

Installing

• Place check_oom.py and check_oom_wrapper in /usr/lib/nagios/plugins.
• If you have a different file path for your plugins, you will need to recompile check_oom_wrapper.c after modifying the REAL_PATH definition on line 3. Use gcc -o check_oom_wrapper check_oom_wrapper.c
• Set the setuid flag on the wrapper file:

sudo chmod u+s /usr/lib/nagios/plugins/check_oom_wrapper

As a future improvement, it would be nice to detect whether the script is running as root, and only call setuid() on the Python subprocess if necessary.

usage: check_oom.py [-h] [-m {warning,critical,default}] [-v]

Check for OOM killer events

optional arguments:
  -h, --help            show this help message and exit
  -m {warning,critical,default}, --mode {warning,critical,default}
                        Mode of results for this check: warning, critical,
                        default
  -s, --short           If this option is specified, check ignores dmesg OOM
                          problems older then 24 hours
  -v, --verbose         Show verbose output from demsg about OOM killer events

check_oom.py: v.1.1 by Dmytro Prokhorenkov