How to Install and Configure Nagios Core Server on Ubuntu/Debian/Linux Mint

Welcome to totatca.com! In this article, we will explore How to Install and Configure Nagios Core Server on Ubuntu/Debian/LinuxMint operating system.

Nagios Core is a powerful and open-source monitoring tool that allows you to monitor the availability and performance of network resources, services, and applications on your system.

Let’s embark on the journey of installing and configuring Nagios Core Server on Ubuntu to enjoy the benefits of reliable and convenient system monitoring.

Prerequisites

• Operating system:
  • Ubuntu 22.04 LTS | 20.04 LTS | 18.04 LTS
  • Debian 9/10/11
  • LinuxMint
• User privileges: root or non-root with sudo privileges.

Read more

• How to Add Linux Host to Nagios Server | Monitoring Linux Host
• How to Set Up a Static IP Address on Ubuntu Desktop
• How to Install and Configure DNS Server on Ubuntu 22.04 20.04 18.04 LTS
• How to Install and Configure RocketChat Server on Ubuntu 22.04 | 20.04 LTS
• Squid Proxy – Install and Configure Squid Proxy Server on Ubuntu

Step 1 – Update system

To ensure that your system has the latest package information and security updates, run the following command:

sudo apt update && sudo apt upgrade -y

Step 2 – Install Packages Required by Nagios Core

Install the necessary packages required by Nagios by running the following command:

sudo apt install -y autoconf bc gawk dc build-essential gcc libc6 make wget unzip apache2 php libapache2-mod-php libgd-dev libmcrypt-dev make libssl-dev snmp libnet-snmp-perl gettext

Step 3 – Download and Extract Nagios Core

First, create a directory named nagioscore and navigate to it

mkdir nagioscore

cd nagioscore

Output:

Next, download Nagios Core from the official website using the following command:

sudo wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.13.tar.gz

Note: At the time of writing, the latest version is 4.4.13. You can refer to the latest version if available here

After downloading, extract the downloaded file.

sudo tar -xvf nagios-4.4.13.tar.gz

Verify the extracted directory

ll

Output:

Step 4: Compile and Install Nagios

To compile and install Nagios, follow these steps:

First, go to the nagios-4.4.13 directory

cd nagios-4.4.13

Output:

Compile Nagios source code and define the Apache virtual host configuration for Nagios. Run the following commands:

sudo ./configure --with-httpd-conf=/etc/apache2/sites-enabled

sudo make all

Next, create the Nagios user and group, and add the www-data Apache user to the nagios group

sudo make install-groups-users

sudo usermod -a -G nagios www-data

Output:

Run the following commands to install Nagios binaries, service daemon script, and the command mode

sudo make install

sudo make install-daemoninit

sudo make install-init

sudo make install-commandmode

Output:

And run the following command to install the sample script configuration:

sudo make install-config

Then run the following command to install the Apache configuration for Nagios and activate the mod_rewrite and mode_cgi modules:

sudo make install-webconf

sudo a2enmod rewrite cgi

Output:

Finally, create a new Nagios Admin user named nagiosadmin using the following command:

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

Output:

Step 5 – Install and Configure Nagios Plugins and NRPE Plugins

To expand the monitoring capabilities of Nagios, we need to install Nagios Plugins and NRPE Plugin. Nagios Plugins provide pre-built plugins to check the status and metrics of servers, services, and applications. NRPE Plugin allows Nagios to access and execute plugins remotely on servers.

Installing and configuring Nagios Plugins and NRPE Plugins will enable us to maximize Nagios’ monitoring capabilities and extend the monitoring of resources and information from other servers in the network.

Continuing with Step 5, we will proceed with the installation and configuration of Nagios Plugins and NRPE Plugin to ensure that Nagios operates fully and effectively.

Install Nagios Plugins and NRPE Plugins

Run the following command to install Nagios Plugins and NRPE Plugins

sudo apt install monitoring-plugins nagios-nrpe-plugin -y

Configure Nagios Plugins and NRPE Plugins

Once Nagios Plugins and NRPE Plugins are installed, navigate to the /usr/local/nagios/etc directory

cd /usr/local/nagios/etc/

ls

Now, create a new directory named servers for storing all server host configuration

sudo mkdir servers

ls

Output:

Next, using the vim editor open the nagios.cfg config file

sudo vim nagios.cfg

Uncomment the line below to define the server hosts configuration

cfg_dir=/usr/local/nagios/etc/servers

Once done, save and exit the file by pressing the Esc key, entering the command :x, and then pressing Enter

Next, open the resource.cfg config file

sudo vim resource.cfg

Edit the line below to define the path binary files of Nagios Monitoring Plugins

$USER1$=/usr/lib/nagios/plugins

Once done, save and exit the file by pressing the Esc key, entering the command :x, and then pressing Enter

And open the objects/contacts.cfg config file

sudo vim objects/contacts.cfg

Edit the line below to define the nagios admin email contacts

define contact{
        ......
        email             your-email
}

Once done, save and exit the file by pressing the Esc key, entering the command :x, and then pressing Enter

Finally, open objects/commands.cfg config file

sudo vim objects/commands.cfg

Add new content below to the end of the file.

define command{
        command_name check_nrpe
        command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
}

Once done, save and exit the file by pressing the Esc key, entering the command :x, and then pressing Enter

Step 6 – Adjust Firewall

To remotely manage Nagios server, you need to allow the Apache service (and SSH if desired) through the UFW firewall. Skip this step if you do not want UFW firewall to be running on your system.

sudo ufw enable

sudo ufw allow 80

sudo ufw allow 443

sudo ufw allow 22

sudo ufw reload

sudo ufw status

Output:

Step 7 – Access Nagios Core Server via the web interface

First, restart Apache and Nagios services to apply the changes:

sudo systemctl restart apache2

sudo systemctl restart nagios

Next, enable it to auto-start at boot time

sudo systemctl enable apache2

sudo systemctl enable nagios

And check the status of Apache and Nagios services, and ensure it’s running:

sudo systemctl status apache2

sudo systemctl status nagios

Output:

Now, access address HTTP://IP-SERVER/nagios or HTTP://YOUR-DOMAIN/nagios to access the Nagios server. If everything is installed and configured correctly, you will see something like the image below.

Conclusion

That’s it! Through this article on How to Install and Configure Nagios Core Server on Ubuntu/Debian/LinuxMint, we have successfully installed Nagios Core on the Ubuntu system. In the upcoming articles, we will explore together how to add hosts to the Nagios Server.

Thank you for reading !!!

Video