SystemExecuteMonitor

If you need to run a system call or a script to determine a service status, use the SystemExecuteMonitor. The monitor calls a script or system command and determines service status based on the return of a `0` or a `non-0` exit code. As an alternative, the output of the system call can be matched against a banner. If the banner is part of the output, the status is interpreted as up. If the banner is not available in the output, the status is determined as down.

Monitor facts

 Class Name `org.opennms.netmgt.poller.monitors.SystemExecuteMonitor`

Configuration and use

Table 1. Monitor-specific parameters for the SystemExecuteMonitor
Parameter Description Default

Required

script

The system call to run.

n/a

Optional

args

The arguments to hand over to the system call. It supports variable replacement, see below.

n/a

banner

A string that is matched against the output of the system-call. If the output contains the banner, the service is determined as UP.

n/a

The parameter `args` supports variable replacement for the following set of variables.

 Always providing a script output with a more detailed test error makes it easier to diagnose the problem when the nodeLostDown event occurs.
Table 2. Variables that can be used in the configuration
Variable Description

${timeout} Timeout in milliseconds, based on service configuration.${timeoutsec}

Timeout in seconds, based on service configuration.

${retry} Amount of retries based on service configuration.${svcname}

Service name based on service configuration.

${ipaddr} IP-address of the interface the service is bound to.${nodeid}

Nodeid of the node the monitor is associated with.

${nodelabel} Nodelabel of the node the monitor is associated with. This monitor implements the Common Configuration Parameters. Examples Placeholder use ``````<parameter key="args" value="-i$\{ipaddr} -t $\{timeout}"/> <parameter key="args" value="http://$\{nodelabel}/$\{svcname}/static"/>`````` Exit status example ``````<service name="Script_Example" interval="300000" user-defined="true" status="on"> <parameter key="script" value="/opt/opennms/contrib/Script_Example.sh"/> <parameter key="timeout" value="5000"/> </service> <monitor service="Script_Example" class-name="org.opennms.netmgt.poller.monitors.SystemExecuteMonitor"/>`````` ``````#!/usr/bin/env bash # ...some test logic RESULT="TEST OK" if [[ "TEST OK" == "${RESULT}" ]]; then
echo "This test passed"
exit 0
else
echo "This test failed because of ..."
exit 1
fi``````
``````<service name="Script_Example" interval="300000" user-defined="true" status="on">
<parameter key="script" value="/opt/opennms/contrib/Script_Example.sh"/>
<parameter key="banner" value="PASSED"/>
<parameter key="timeout" value="5000"/>
</service>

<monitor service="Script_Example" class-name="org.opennms.netmgt.poller.monitors.SystemExecuteMonitor"/>``````
``````#!/usr/bin/env bash

# ...some test logic

RESULT="TEST OK"

if [[ "TEST OK" == "\${RESULT}" ]]; then
echo "PASSED"
else
echo "FAILED"
fi``````