Installing Nagios on Debian Latest

In this tutorial, we will walk through the installation process of Nagios on Debian.

Prerequisites

Before we start the installation process, make sure the following prerequisites are fulfilled.

You need to have root privileges on the server
Update the package index and upgrade the system packages to their latest versions.

$ sudo apt update && sudo apt upgrade

Step 1: Install Dependencies

Nagios requires various packages to be installed on the Debian system. To install these dependencies, run the following command:

$ sudo apt install -y autoconf gcc libc6 make wget unzip apache2 php libapache2-mod-php7.3 libgd-dev

Step 2: Download Nagios and its Plugins

Download the latest Nagios source files from the Nagios website using the following command:

$ cd /opt/
$ sudo curl -L -O https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.6.tar.gz

Next, download the Nagios Plugins:

$ sudo curl -L -O https://nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz

Extract the downloaded files:

$ sudo tar -zxvf nagios-4.4.6.tar.gz
$ sudo tar -zxvf nagios-plugins-2.3.3.tar.gz

Step 3: Compile and Install Nagios

To install Nagios, go to the extracted directory and execute the configure, make, and make install commands.

$ cd nagios-4.4.6/
$ sudo ./configure --with-command-group=nagcmd
$ sudo make all
$ sudo make install
$ sudo make install-commandmode
$ sudo make install-init
$ sudo make install-config

Step 4: Compile and Install Nagios Plugins

Next, install the Nagios plugins by going to the extracted plugin directory and running the same set of commands.

$ cd ../nagios-plugins-2.3.3/
$ sudo ./configure --with-nagios-user=nagios --with-nagios-group=nagios --with-openssl
$ sudo make
$ sudo make install

Step 5: Setup Nagios User and Group

Create the Nagios user and group to run Nagios on the system.

$ sudo useradd nagios
$ sudo groupadd nagcmd
$ sudo usermod -a -G nagcmd nagios

Step 6: Configure Apache for Nagios

Nagios has a web interface that requires Apache to serve web pages. Configure Apache to serve Nagios pages.

$ sudo make install-webconf
$ sudo a2enmod rewrite
$ sudo systemctl restart apache2

Step 7: Firewall

Nagios uses port 80 for its web interface. Open the HTTP port on the firewall using the following command:

$ sudo ufw allow http/tcp

Step 8: Verify the Installation

Run the following command to start the Nagios service:

$ sudo systemctl start nagios

Navigate to http://localhost/nagios/ in your web browser to ensure Nagios is up and running correctly.

Conclusion

Congratulations! You have successfully installed Nagios on Debian Latest. Nagios can now be used for monitoring hosts and services on your server.