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Nagios XI - Terminology Overview

Nagios XI Terminology Overview

This guide will cover common terminology used when working with Nagios XI and how each item relates to the overall monitoring system.  Each item will be covered at a high level. 



A host in Nagios XI is a specific host being monitored with a unique hostname.  While primarily a host is a physical or virtual server, the host object could also be defined as a logical container for 0 or more services.



Services in Nagios XI are unique items being monitored for a specific host.  While these may be proper services, i.e. checking if a Windows or Linux service is running, they also are the name gives for ALL items being monitored, such as Memory Usage, Disk Usage, CPU Utilization, Load, Bandwidth Utilization, etc.



Plugins in Nagios XI are what is used to perform the monitoring checks for hosts and services.  A plugin can be created in many different languages, as long as the program/script can be executed from the Linux command line, print any output to display in the UI/notifications and exit with a status code which will pertain to status of the check.


Numeric Value

Service Status

Status Description



The plugin was able to check the service and it appeared to be functioning properly



The plugin was able to check the service, but it appeared to be above some "warning" threshold or did not appear to be working properly



The plugin detected that either the service was not running or it was above some "critical" threshold



Invalid command line arguments were supplied to the plugin or low-level failures internal to the plugin (such as unable to fork, or open a tcp socket) that prevent it from performing the specified operation. Higher-level errors (such as name resolution errors, socket timeouts, etc) are outside of the control of plugins and should generally NOT be reported as UNKNOWN states.


As part of the output, plugins often return performance data for the particular check performed.  This data is used to create performance graphs over time.  Performance data comes at the end of the output following a | (pipe) symbol.

See the Plugin Development Guidelines for detailed information on making your own plugins, or visit the Nagios Exchange to find thousands of Nagios plugins created by Nagios Enterprises, and other community members. 


Dashboards and Dashlets

In Nagios XI each user has the ability to create an unlimited number of dashboard to display information that is most important to the individual user.  Each dashboard can contain as many dashlets as the user would like to add.  Dashlets are small elements that found throughout the Nagios XI interface distinguished by the dashify icon.

If a user clicks on the dashify icon they will have the ability to select which dashlet they would like to add the dashlet to.  After the dashlet has been added to a dashboard a user can resize the dashlet as to the size they desire and also dashlets can be dragged into different locations within the dashboard.  When satisfied the user can click the arrow icon in the top right of the dashlet to lock it in place.

There is also a special dashboard called SCREEN, if a user adds a dashlet to the SCREEN dashboard it will display on every page in the UI. 



Wizards in Nagios XI help users configure host and services by breaking down the setup into easy step-by-step form.  Users will enter information such as hostname, and then define which element of the wizard they want to use, define warning and critical threshold, select contacts / contact groups, hostgroups /servicegroups and parent host.

Wizards are programmed to know which services are to use certain check commands and how to pass the arguments to the commands, they take all the information input from the user running the wizard and defines the appropriate arguments for the command.

When the wizard has all the information it needs, the final step will write all the needed configuration files to the Core configuration Managers import directory and then will Apply Configuration.  This process imports the wizard configuration files into the configuration database, then write out the configuration for the underlying Nagios Core engine, tests the configuration and if valid restarts the monitoring engine to start monitoring the newly added host/services.

Some wizards in Nagios XI would be called Smart Wizards, whereas interactively they will reach out to the device to be monitored and return information about the device.  the Switch/Router Wizard would be an example of a Smart Wizard, it reached out to the switch or router to get a list of interfaces to be monitored.

New wizards can be added to Nagios XI by uploading through Admin -> Manage Config Wizards.



Components are the building blocks for extending the capabilities of Nagios XI. Because if the extensive callback system built into Nagios XI, components can be used to extend virtually any part of Nagios XI including but not limited to, adding reports, adding new user notification types, adding functionality to interact with external systems such as Nagios Incident Manager, Nagios Reactor or any 3rd party software.

There are 2 different types of components, core components and user components. Typically core components are overwritten with every upgrade, and cannot be deleted, whereas user components can be deleted through the UI without causing internal problems.

New components can be added to Nagios XI by uploading through Admin -> Manage Components


Final Thoughts

For any support related questions please visit the Nagios Support Forums at:


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