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Nagios plugin support for IBM i



Nagios provides enterprise-class Open Source IT monitoring, network monitoring, server and applications monitoring. A released version of IBM i plug-in for Nagios has been created to support monitoring IBM i systems. The plug-in supports multiple monitoring matrix and provides customized SQL ability which can be used to create self-defined monitoring matrix.


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Nagios provides enterprise-class Open Source IT monitoring, network monitoring, server and applications monitoring. IBM i plugin for Nagios provides the monitoring capabilities for IBM i systems. There are several key values that this plugin provides list as follows:

  • Multi-system monitoring. Nagios is well known as multi-system monitoring tool. Now it is possible to monitor multiple IBM i systems through Nagios. There are different levels of views that can help the administrators understanding the overall health status of the entire data center, a group of IBM i systems, single IBM i partitions, services of OS and applications, and so on. For large customers and MSPs, this capability can make the monitoring hundreds of IBM i systems to be practical.
  • Self-define matrix support. Most of the monitoring tools for IBM i in the market normally provide pre-defined monitoring matrix. The users are limited to choose from selected items to monitor. The Nagios plugin for IBM i not only provides predefined common matrix, but also functions to allow users to define their own matrix. Users could leverage SQLs to extend the matrix to be monitored. Hundreds of options can be provided basing on different SQLs on top of IBM i services.
  • Open source. The IBM i plugin is open source software that the users can do much deeper customization to extend the project. Pluggable infrastructure has been provided that the users could either create new classes or modify the existing functions to meet the specific monitoring goals. If the users choose to do code modifications, they only need to focus on the monitoring logic and matrix retrieving.
  • Nothing needs to be installed on IBM i systems being monitored. The plugin uses JTOpen to connect to the target IBM i systems and there is no daemon running to collect the monitoring data. For security considerations, the user can configure SSL over the connection as well. For most of the IBM i customers, the IBM i administration tools already use JTOpen connections so that there is no extra thing to be installed on IBM i side.

IBM i plugin works for both NagiosXI and Nagios Core. Extended GUI pages have been provided in NagiosXI to simplify the configurations of IBM i matrix and services.


If you are Nagios Core user, you need to go through the steps described in the following link. 

Setting Up Nagios Plug-in for IBM i


There are different ways to monitor IBM i systems with Nagios plugin. The plugin provides multiple Nagios commands to do basic monitoring. The following table shows all the basic matrix that this plugin can monitor.

Command name


CPU utilization

Retrieve the CPU utilization for the entire system

CPU usage for job

Retrieve the CPU usage for a specific job

CPU overload job number

Retrieve the number of jobs that exceeds the expected CPU usage

Temp storage check

Retrieve top N jobs that have the most temp storage usage

Number of logon users

Retrieve the number of users that currently log on to the system

Disk status check

Retrieve the disk status

ASP usage percentage

Retrieve the ASP usage percentage of the entire system

Job info

Retrieve job information in a specific sub system

Long running SQL

Retrieve the longest running SQL

Number of active jobs

Retrieve the number of active jobs on the system

Page faults check

Retrieve the page faults

Message check

Retrieve the messages from a specific message queue

Specific message check

Retrieve the status whether a specific message ID is found in a specific message queue

Basic info check

Retrieve the basic information of an IBM i system

Customize SQL Use customized SQLs to monitor different matrix on the system

The last row of the above tabe regards to the powerful feature that the users can do custom SQL monitoring. Self-defined commands can be configured to monitor any result returned by a SQL query. Details can be found here:

The NagiosXI installation packages since 2019-09-26 contain IBM i plugins and GUI wizards by default. As shown in the following picture, two GUI wizards are provided to support configuring services and customized SQL for IBM i monitoring. Details could be found in the below link.

IBM i configuration wizards in NagiosXI


If you have more questions about IBM i plugin for Nagios, please visit this link: Nagios for i FAQs

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Document Information

Modified date:
22 July 2020