Nagios is a free and opensource network and alerting engine used to monitor various devices, such as network devices, and servers in a network. It supports both Linux and Windows OS and provides an intuitive web interface that allows you to easily monitor network resources. When professionally configured, it can alert you in the event a server or a network device goes down or malfunctions via email alerts. In this topic, we shed light on how you can install and configure Nagios core on RHEL 8 / CentOS 8.
Prerequisites of Nagios Core
Before we begin, perform a flight check and ensure you have the following:
- An instance of RHEL 8 / CentOS 8
- SSH access to the instance
- A fast and stable internet connection
With the above requirements in check, let’s roll our sleeves!
Step 1: Install LAMP Stack
For Nagios to work as expected, you need to install LAMP stack or any other web hosting stack since it’s going to run on a browser. To achieve this, execute the command:
# dnf install httpd mariadb-server php-mysqlnd php-fpm
You need to ensure that Apache web server is up and running. To do so, start and enable Apache server using the commands:
# systemctl start httpd
# systemctl enable httpd
To check the status of Apache server run
# systemctl status httpd
Next, we need to start and enable MariaDB server, run the following commands
# systemctl start mariadb
# systemctl enable mariadb
To check MariaDB status run:
# systemctl status mariadb
Also, you might consider hardening or securing your server and making it less susceptible to unauthorized access. To secure your server, run the command:
# mysql_secure_installation
Be sure to set a strong password for your MySQL instance. For the subsequent prompts, Type Yes and hit ENTER
Step 2: Install Required packages
Apart from installing the LAMP server, some additional packages are needed for the installation and proper configuration of Nagios. Therefore, install the packages as shown below:
# dnf install gcc glibc glibc-common wget gd gd-devel perl postfix
Step 3: Create a Nagios user account
Next, we need to create a user account for the Nagios user. To achieve this , run the command:
# adduser nagios
# passwd nagios
Now, we need to create a group for Nagios and add the Nagios user to this group.
# groupadd nagiosxi
Now add the Nagios user to the group
# usermod -aG nagiosxi nagios
Also, add Apache user to the Nagios group
# usermod -aG nagiosxi apache
Step 5: Download and install Nagios core
We can now proceed and install Nagios Core. The latest stable version in Nagios 4.4.5 which was released on August 19, 2019. But first, download the Nagios tarball file from its official site.
To download Nagios core, first head to the tmp directory
# cd /tmp
Next download the tarball file
# wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.5.tar.gz
After downloading the tarball file, extract it using the command:
# tar -xvf nagios-4.4.5.tar.gz
Next, navigate to the uncompressed folder
# cd nagios-4.4.5
Run the commands below in this order
# ./configure --with-command-group=nagcmd
# make all
# make install
# make install-init
# make install-daemoninit
# make install-config
# make install-commandmode
# make install-exfoliation
To setup Apache configuration issue the …
