A plugin for Nagios (and other compatible monitoring services) to check and monitor the main memory usage of one or more unix process. A single process can be located by pid or a pidfile or a single or multiple processes by filtering the process list using pid, gid, file name, and command line.
I had an actual use case where I needed to monitor the main memory usage (resident set size) of a group of httpd-processes running under different users and locations.
Looking around for a solution it seemed that this requirement was more or less abundant. So, I have written this plugin to solve my needs and maybe somebody else's needs.
Copy the check_process_memory_usage file to your Nagios plugins directory, e.g.:
git clone https://github.com/aalborgunilib/check-process-memory-usage
cd check-process-memory-usage
sudo cp plugins/check_process_memory_usage /usr/lib64/nagios/plugins/
sudo chmod 755 /usr/lib64/nagios/plugins/check_process_memory_usage
Install Perl dependencies for the plugin via e.g. cpanm. (Please stay within the check-process-memory-usage directory):
curl -L https://cpanmin.us | perl - --sudo App::cpanminus
cpanm --sudo --installdeps .
Compilation of the Perl dependencies may require the installation of software development tools on the server (gcc).
Now, check to see if the plugin is working:
plugins/check-process-memory-usage
You should get something in the line of:
PROCESS_MEMORY_USAGE OK - RSS 192M - SIZE: 8.8G | 'resident set size'=196348KB;; 'virtual memory size'=9201472KB;;
The reported metrics are resident set size and virtual memory size. The first being representative of the non-swapped physical memory that a process is using.
To check for a specific process you can try:
plugins/check_process_memory_usage --verbose --uid root --cmndline /usr/sbin/sshd
You should get something like this:
UID GID PID FNAME CMNDLINE
root root 1085 sshd /usr/sbin/sshd -D
PROCESS_MEMORY_USAGE OK - RSS 4.3M - SIZE: 111M | 'resident set size'=4308KB;; 'virtual memory size'=112812KB;;
The UID root and CMNDLINE part /usr/sbin/sshd should be coloured red on an ANSI terminal to show how the filters matched the process list (when using --verbose).
Usage: check_process_memory_usage
[ -c|--critical=<critical threshold in kB> ]
[ -w|--warning=<warning threshold in kB> ]
[ -n|--no_filter_match ]
[ -f|--fname=<file name filter> ]
[ -C|--cmndline=<command line filter> ]
[ -u|--uid=<uid or user name filter> ]
[ -g|--gid=<gid or group name filter> ]
[ -p|--pid=<pid> ]
[ -P|--pidfile=<pidfile to get pid> ]
[ -t|--timeout=<timeout> ]
[ -v|--verbose ]
The -c|--critical and -w|--warning defines the standard Nagios service check thresholds (in kB). The critical and warning thresholds can be omitted e.g. if you would like to just graph the memory usage. The thresholds are matched against RSS (resident set size) memory.
-n|--no_filter_match will let the plugin exit with an OK even if none of the filters matched up against a process. This will avoid the plugin of sending an UNKNOWN status in case the process has died or has not yet been started (many will probably monitor this by using another plugin). Metrics are still reported in either case as being 0KB.
-f|--fname will filter the process list by the exact base name of the process's executable file. E.g. --fname=sshd will match sshd processes but --fname=ssh will not.
-C|--cmndline will filter the process list by matching against the command with all its arguments as a string. The match is done as a single index match. E.g. --cmndline=ssh will match the commandline /usr/sbin/sshd -D. Also, the plugin will automatically filter out itself from the process list as the cmndline-option will always return a selfmatch.
-u|--uid will filter the process list by matching against the uid (or user name). Mapping from uid to user name is done automatically if the uid is not all numeric.
-g|--gid as uid but with group id (or group name).
Filters can be combined to narrow down a process or group of processes. E.g. --fname=httpd --cmndline=config/proxy.conf to filter httpd processes running with a certain configuration file.
-p|--pid will select the process with the given pid.
-P|--pidfile as pid but will read the pid from the pidfile.
-t|--timeout is the plugin timeout. If timeout is reached, the check will bail out and issue an UNKNOWN state.
-v|--verbose outputs a process list (much like ps -eo user,group,pid,fname,command) matching the filters and color the matches for you to easilly check that the filters you specified are working to your preferences.
Copyright (c) 2018 Kasper Løvschall and Aalborg University Library
This software is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See Perl Licensing.