Install Nagios Core in Ubuntu 20.04.

Please follow the Below steps;

1.Update the Packages;

#sudo apt update

2.Install the Required Packages;

sudo apt install wget unzip curl openssl build-essential libgd-dev libssl-dev libapache2-mod-php php-gd php apache2 -y

3.Download Nagios Core Setup files. To download the latest version, visit the official releases site.

#wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.6.tar.gz

4.Extract the Files;

#sudo tar -xvf nagios-4.4.6.tar.gz

5.Navigate to the setup directory;

#cd d nagios-4.4.6

6.Run the Nagios Core configure script;

#sudo ./configure

7.#sudo make all

8.Make and install group and user;

#sudo make install-groups-users

9.Add www-data directories user to the nagios group;

#sudo usermod -a -G nagios www-data

10.Install Nagios;

#sudo make install

11.#sudo make install-init

12.Install and configure permissions on the configs’ directory.

#sudo make install-commandmode

13.Install sample config files.

#sudo make install-config

14.Install apache files.

#sudo make install-webconf

15.Enable apache rewrite mode.

#sudo a2enmod rewrite

16.Enable CGI config.

#sudo a2enmod cgi

17.Restart the Apache service.

#sudo systemctl restart apache2

18.Create a user and set the password when prompted.

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

Install Nagios Plugin;

1.Go to Home Directory Again

#cd

2.Download Plugins;

#sudo wget https://nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz

3.Extract the downloaded plugin.

#sudo tar -zxvf nagios-plugins-2.3.3.tar.gz

4.Navigate to the plugins’ directory.

#cd nagios-plugins-2.3.3/

5.Run the plugin configure script.

#sudo ./configure — –with-nagios-user=nagios –with-nagios-group=nagios

6.Compile Nagios Core plugins.

#sudo make

7.Install the plugins.

#sudo make install

Verify Nagios Configuration;

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

2.Start the Nagios service.

#sudo systemctl start nagios

3.Enable Nagios service to run at system startup.

#sudo systemctl enable nagios

Access Nagios Web-Interface;

1.Open Your web Browser and type below url

http://YOURIP/nagios

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