Author: Sahil Suri

Introduction In our previous two articles we’ve explained how to install Nagios core on a Centos 7 system and how to install Nagios plugin and the Nagios Remote Plugin Executor. In this article we will explain how to configure Nagios so that we can have the web interface up and running. Note that this needs to be done only once on the Nagios server. You may make amendments as deemed necessary. Update the Nagios main configuration file: The nagios.cfg file is the heart of your nagios core configuration. The location of this file may vary depending on where you installed nagios. The general location of the file is /usr/local/nagios/etc/nagios.cfg This file contains information about the location of other configuration files and template files which nagios will read in order to determine which assets are to be monitored and which services on those assets are to be monitored. We can define the location to these configuration files using the cfg_file directive. By default Nagios already has most of the configuration files set up and ready to use as shown below: [ssuri@linuxnix:/usr/local/nagios/etc] $ grep -E '^cfg_file' nagios.cfg cfg_file=/usr/local/nagios/etc/objects/commands.cfg cfg_file=/usr/local/nagios/etc/objects/contacts.cfg cfg_file=/usr/local/nagios/etc/objects/timeperiods.cfg cfg_file=/usr/local/nagios/etc/objects/templates.cfg cfg_file=/nagiosap/objects/hostgroups/linux.cfg cfg_file=/usr/local/nagios/etc/objects/localhost.cfg We will talk about the purpose of these configuration files in greater detail in later articles. You could also define a directory location and tell nagios to read all files ending with .cfg extension within that directory. Add...

Introduction In our previews article we walked you through installing nagios core on a Centos 7 system. In this article we will explain how to install Nagios plugins and the Nagios Remote Plugin Executor (NRPE) package. How does Nagios work? Nagios core runs from a central server which holds the configuration files. It runs active checks to monitor the state of services like HTTP and SSH, check if the server is up via ICMP and also monitor resource consumption like in the form of CPU load, memory utilization etc. The core server has a huge library of plugins and much of the functionality and flexibility of Nagios is derived from the use of these plugins. What are Nagios plugins? Plugins are compiled executable or scripts (Perl scripts, shell scripts, etc.) that can be run from a command line to check the status or a host or service.  Nagios uses the results from plugins to determine the current status of hosts and services on your network. Nagios will execute a plugin whenever there is a need to check the status of a service or host.  The plugin does something to perform the check and then simply returns the results to Nagios. It will process the results that it receives from the plugin and take any necessary actions. Installing Nagios plugins The plugins which provide the most commonly needed and used monitoring...