## Distributed Systems

If Nagios is implemented as a distributed system you have to decide where PNP should be installed.

From a technical view this question is not important. PNP can be installed on the slave(s) as well as on the master server. Or only on the master?

If PNP is running on the master you have to make sure that data passed via send_nsca from the slave server(s) contains performance data. Often another check command is used on the master.

To help PNP on the master to recognize which check command was used on the slave to collect the information process_perfdata.pl responds to an additional field at the end of the performance data.

    OK - 127.0.0.1: rta 2.687ms, lost 0% | rta=2.687ms;3000.000;5000.000;0; pl=0%;80;100;; [check_icmp]

If PNP finds a string enclosed in brackets at the end of performance data it will be recognized as check command and will be used as PNP template.

Nagios documentation related to this topic can be found here. The command used in the documentation can be adapted easily.

    define command{
    	command_name	submit_check_result
    	command_line	/usr/local/nagios/libexec/eventhandlers/submit_check_result $HOSTNAME$ '$SERVICEDESC$' $SERVICESTATE$ '$SERVICEOUTPUT$'
    	}

should be changed to

    define command{
    	command_name	submit_check_result
    	command_line	/usr/local/nagios/libexec/eventhandlers/submit_check_result $HOSTNAME$ '$SERVICEDESC$' $SERVICESTATE$ '$SERVICEOUTPUT$ | $SERVICEPERFDATA$ [$SERVICECHECKCOMMAND$]'
    	}

## check_multi plugin

The plugin check_multi is one of the first plugins which uses new features of Nagios 3.x. Check_multi can execute multiple Nagios plugins but returns only results like a single service. The output of check_multi comprises of several lines to be able to display the amount of information.

This results in some difficulties for PNP which has to extract the information of several plugins from the performance data. Together with Matthias Flacke, developer of check_multi, we have found a solution to assign the data to the appropriate plugins.

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