Install Nagios Core from Source Along with Plugins

This lab goes through the procedure of compiling and installing Nagios Core directly from the source. This is the long way around, but it comes with advantages such as having the latest version of Nagios Core with all the features. A secondary benefit is a greater understanding of the Nagios Core structure, how it is intended to work, and what files are where.

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Download and Compile Nagios Core

Edit the SELinux config file.
```
sudo vim /etc/selinux/config
```
Change the line defining the SELINUX variable to the following.
```
SELINUX=permissive
```
Save the changes and exit the editor.
Modify the current mode for SELinux.
```
sudo setenforce 0
```
Check the current SELinux mode. Verify we are in permissive mode.
```
getenforce
```

Install all necessary prerequisites.

sudo yum install -y gcc glibc glibc-common wget unzip httpd php gd gd-devel perl postfix

Download the Nagios Core.

wget https://github.com/NagiosEnterprises/nagioscore/archive/nagios-4.4.3.tar.gz

Extract the files from the repository.
```
tar -xvzf nagios-4.4.3.tar.gz
```
Navigate to the appropriate directory.
```
cd nagioscore-nagios-4.4.3
```

Run the configuration script.
```
./configure
```
Compile the necessary files.
```
sudo make all
```

Install Nagios

Create a user and group for Nagios.
```
sudo make install-groups-users
```
Add the Nagios user to the Apache group.
```
sudo usermod -a -G nagios apache
```
Install the necessary binaries.
```
sudo make install
```
Configure Nagios to run as a daemon.
```
sudo make install-daemoninit
```
Enable the web server.
```
sudo systemctl enable httpd.service
```
Install the Nagios command mode.
```
sudo make install-commandmode
```
Install sample files for Nagios.
```
sudo make install-config
```
Install Apache configuration files.
```
sudo make install-webconf
```

Configure and Run Nagios

Configure a firewall rule for Nagios.

sudo firewall-cmd --zone=public --add-port=80/tcp --permanent

Reload the firewall.
```
sudo firewall-cmd --reload
```
Create a "nagiosadmin" user and remember the password you assign. The password is up to you.
```
sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
```
Start the web server.
```
sudo systemctl start httpd.service
```
Start the Nagios service.
```
sudo systemctl start nagios.service
```
Check that the web server is running.
```
sudo systemctl status httpd
```
Check that Nagios is running
```
sudo systemctl status nagios
```

Add Nagios Plugins and Verify Nagios

Open up a browser and navigate to the public IP address provided in the lab instructions. Attempt to login using nagiosadmin and the password you supplied in a previous step.

Install necessary prerequisites.

sudo yum install -y gcc glibc glibc-common make gettext automake autoconf wget openssl-devel net-snmp net-snmp-utils epel-release unzip perl-Net-SNMP

Download the plugins.

wget https://github.com/nagios-plugins/nagios-plugins/archive/master.zip

Unzip the file.
```
unzip master.zip
```
Nagivate to the appropriate directory.
```
cd nagios-plugins-master/
```
Run the setup command.
```
./tools/setup
```
Run the configure command.
```
sudo ./configure
```
Compile the necessary files.
```
sudo make
sudo make install
```
Restart Nagios.
```
sudo systemctl restart nagios
```

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Install Nagios Core from Source Along with Plugins

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Learning Objectives

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