How To Install Nagios Server In Ubuntu & Debian

Nagios is an open-source monitoring tool that is used to monitor hosts, services, and network devices. It provides real-time monitoring, alerting, and reporting capabilities to help you proactively identify and resolve issues in your IT environment. In this article, we will show you how to install Nagios Server on Ubuntu & Debian, including the prerequisites, installation process, and configuration steps.

Nagios Server is the central component of the Nagios monitoring system. It collects data from remote hosts, services, and network devices, and displays the information in a web interface. Nagios Server can be installed on a variety of operating systems, including Ubuntu & Debian. In this article, we will focus on installing Nagios Server on Ubuntu & Debian systems.

How to Monitor remote Linux host using Nagios
How to Monitor remote Windows host using Nagios

Prerequisites

Before installing Nagios Server, you should have the following prerequisites:

• A fresh installed Ubuntu or Debian system.
• Shell access with sudo privileged user.
• Internet connection to download the required packages.

Step 1: Update the System

Before installing any new packages, it is always recommended to update the system with the latest security patches and bug fixes. Run the following command to update the system:

sudo apt update && sudo apt upgrade 

Step 2: Install Required Packages

Before installing Nagios, you need to install some required packages including Apache, PHP, and GCC. Run the following command to install them:

sudo apt install -y build-essential unzip openssl libssl-dev php apache2 apache2-utils 

Step 3: Create a Nagios User and Group

First of all, create a nagios user using the following command:

sudo adduser nagios 

Then create a group for Nagios setup “nagcmd” and add nagios user to this group. Also, add nagios user in the Apache group.

sudo groupadd nagcmd 
sudo usermod -a -G nagcmd nagios 
sudo usermod -a -G nagcmd www-data 

Step 4: Download Nagios Core

You can download Nagios Core from the official website using the wget command. Run the following command to download the latest version of Nagios Core:

wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.5.2.tar.gz 

After downloading the package, extract it using the tar command. Run the following command to extract the package:

tar xzf nagios-4.5.2.tar.gz 

Step 5: Compile and Install Nagios Core

Go to the extracted directory and run the following commands to compile and install Nagios Core:

cd nagios-4.5.2 
sudo ./configure --with-command-group=nagcmd --with-httpd-conf=/etc/apache2/sites-enabled 
sudo make all 
sudo make install 
sudo make install-init 
sudo make install-config 
sudo make install-commandmode 

Now create an Apache configuration file for your Nagios server as below:

sudo make install-webconf 

Now copy event handlers scripts under libexec directory. These binaries provides multiple events triggers for your Nagios web interface.

sudo cp -R contrib/eventhandlers/ /usr/local/nagios/libexec/ 
sudo chown -R nagios:nagios /usr/local/nagios/libexec/eventhandlers 

Step 6: Configure Apache Web Server

We need to setup apache authentication for user nagiosadmin. Until more specific reason use this username as “nagiosadmin” else you would require more changes in configuration.

sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin 

Now enable Apache configuration and restart Apache service to make the new settings take effect.

sudo a2enmod cgi rewrite 
sudo systemctl restart apache2  

Step 7: Install Nagios Plugins

After installing and configuring Nagios core service, Download latest nagios-plugins source and install using the following commands.

wget http://www.nagios-plugins.org/download/nagios-plugins-2.4.9.tar.gz 
tar xzf nagios-plugins-2.4.9.tar.gz 
cd nagios-plugins-2.4.9 

Now compile and install Nagios plugins

sudo ./configure --with-nagios-user=nagios --with-nagios-group=nagcmd --with-openssl 
sudo make 
sudo make install 

Step 8: Start Nagios Service

Use the Nagios commands to verify the Nagios installation and configuration file.

sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg 

After successfully verify start the Nagios core service and enable auto-start on system boot..

sudo systemctl start nagios 
sudo systemctl enable nagios 

Step 9: Access Nagios Web Interface

You can access the Nagios web interface by opening a web browser and entering the following URL:

You will be prompted to enter a username and password. Use the credentials you created in step 6 (nagiosadmin/password) to log in.

Once you are logged in, you will see the Nagios dashboard that displays the status of all the hosts and services being monitored.

Finally, You have successfully installed and configured Nagios Monitoring Server core service in your system. Now visit net article to monitor Linux host and Windows host using Nagios server.

Conclusion

In this article, we have introduced Nagios Server, its importance, and the installation process for Ubuntu & Debian systems. Installing Nagios Server will allow you to monitor your IT environment and ensure that critical systems and services are functioning correctly. By following the steps outlined in this article, you can get started with Nagios Server and take the first step towards proactively managing your IT environment.