check_usolved_linux_realmemory

Overview

This PHP Nagios plugin calculates the real free memory according to http://www.linuxatemyram.com. When you think that your Linux memory is always near to 100% consumed, that is properly not true. Linux calculates the free memory in a special way. This plugin tries to get the memory that is really still free to use.

The plugin also returns performance data.

Authors

Ricardo Klement (www.usolved.net)

Installation

Just copy the file check_usolved_linux_realmemory.php into your Nagios plugin directory. For example into the path /usr/local/nagios/libexec/

Give check_usolved_linux_realmemory.php the permission for execution for the nagios user. If you have at least PHP 5 this plugin should run out-of-the-box.

Make sure to have the PHP SNMP module installed and enabled in your php.ini.

> apt-get install php5-snmp (Ubuntu, Debian, ...) or > yum install php-snmp (RedHat, CentOS, ...)

Usage

Test on command line

If you are in the Nagios plugin directory execute this command:

./check_usolved_linux_realmemory.php -H localhost -C public -w 90 -c 95

This should output something like this:

OK - 18.8% Memory used (1119 MB of 5962 MB), 0% Swap used (0 MB of 7807 MB)

Here are all arguments that can be used with this plugin:

-H <host address>
Give the host address with the IP address or FQDN

-C <snmp community>
Give the SNMP Community String

-w <warn>
Warning treshold in percent

-c <crit>
Critical treshold in percent

[-V <snmp version>]
Optional: SNMP version 1 or 2c are supported, if argument not given version 1 is used by default

[-P <perfdata>]
Optional: Give 'yes' as argument if you wish performace data output

Install in Nagios

Edit your commands.cfg and add the following.

Example for basic check:

define command {
    command_name    check_usolved_linux_realmemory
    command_line    $USER1$/check_usolved_linux_realmemory.php -H $HOSTADDRESS$ -C $_HOSTSNMPCOMMUNITY$ -w $ARG1$ -c $ARG2$
}

Example for using performance data and specific snmp version:

define command {
    command_name    check_usolved_linux_realmemory
    command_line    $USER1$/check_usolved_linux_realmemory.php -H $HOSTADDRESS$ -C $_HOSTSNMPCOMMUNITY$ -V $_HOSTSNMPVERSION$ -w $ARG1$ -c $ARG2$ -P $ARG3$
}

Edit your services.cfg and add the following.

Example for basic check:

define service{
	host_name				Test-Server
	service_description		Memory
	use						generic-service
	check_command			check_usolved_linux_realmemory!90!95
}

Example for using performance data and excluding some partitions:

define service{
	host_name				Test-Server
	service_description		Memory
	use						generic-service
	check_command			check_usolved_linux_realmemory!90!95!yes
}

What's new

v1.0 Initial release