Installing Nagios on Ubuntu 16.04/18.04 LTS

Introduction

Nagios is an open-source software tool that can be used for monitoring servers, networks, and applications. It can alert administrators when it detects problems and can also provide historical data about system performance. Nagios can monitor various services, including HTTP, SMTP, and SSH, and can also monitor host resources such as CPU and disk usage. It is a widely used monitoring tool in IT operations, as it is flexible and can be easily configured to suit different environments.

Requirement

Root permission access.
Basic knowledge of linux commands.

In this post, We will install and configure Nagios Core on ubuntu 16.04/18.04 LTS

Step 1: Install Required Packages

On server side installation and configuration, You need to install all dependencies for nagios-core in your ubuntu 16.04 machine by the following commands, before installation of we need update the repository first as a root user.

sudo -i
apt-get update
apt-get install build-essential openssl unzip apache2 php perl make php-gd libgd-dev libapache2-mod-php libperl-dev libssl-dev daemon wget apache2-utils nagios-nrpe-plugin -y

Step 2: Add Nagios User and Group

You need to create user and group to allow to executite to commands from web user-interfaces, We create nagios user and nagcmd group also need to associate the nagios user with apache user to the part of the nagcmd group by the following commands.

useradd nagios && groupadd nagcmd
usermod -a -G nagcmd nagios && usermod -a -G nagcmd www-data

Step 3: Download Nagios 4.4.3

Now you need to download the nagios-core’ tar files to compile by following the commands.

cd /tmp
wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.3.tar.gz
tar -zxvf /tmp/nagios-4.4.3.tar.gz
cd /tmp/nagios-4.4.3/

Step 4: Nagios Compile

You need to compile the nagios core by using the followin g commands.

./configure --with-nagios-group=nagios --with-command-group=nagcmd --with-httpd_conf=/etc/apache2/sites-enabled/

make all
make install
make install-init
make install-config
make install-commandmode
make install-webconf

Step 5: Nagios username and password

After this You need to create basic authentication using htaccess of nagios web user-interfaces using the commands, put your password to access the nagios web interface.

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

Step 6: Enable Apache2 modules

After this you need to install apache modules cgi by following the commands and restart the apache2 services to get effect.

a2enmod cgi && systemctl restart apache2

Step 7 : Downloading and compile nagios plugin

After that, You need to download and compile the nagios plugin for monitoring the service by following the commands.

cd /tmp
wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
tar -zxvf /tmp/nagios-plugins-2.2.1.tar.gz
cd /tmp/nagios-plugins-2.2.1/
./configure --with-nagios-user=nagios --with-nagios-group=nagios
make
make install

Step 8: Verifying nagios configuration cfg file

Now you need to check the nagios configuration by following the commands.

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

Step 9: On boot enable nagios service and start the nagios process

After this, You need to enable to nagios service to auto start on system boot time and You need to start the nagios services by using following commands.

systemctl start nagios && systemctl enable nagios

Now it’s time to open the browser and open the nagios web url like :-

http://localhost/nagios/

You will be asked for username password, You need to put the nagiosadmin for username and password you have set for htaccess.

Conclusion

In this article, we have performed Creating nagios client and gathering, downloading Nagios Core, accumulating and introducing nagios, Installing apache setup records, Downloading and introducing Nagios center modules, verify,start and empower Nagios administration, Accessing nagios web interface.