Installing Nagios on OpenBSD

Nagios is a powerful monitoring system that allows you to monitor hosts, services, and network devices. In this tutorial, we will be installing Nagios on OpenBSD.

Prerequisites

Before we begin, ensure that you have the following installed on your OpenBSD system:

• OpenBSD version 6.7 or later
• A web server (Apache or Nginx)

Install Dependencies

First, let's install the necessary dependencies:

sudo pkg_add -v gd-2.2.5p3 freetype-2.10.0p0 png-1.6.37p1 jpeg-8.4.2p2

Download Nagios

Visit the official Nagios website and download the latest version of Nagios Core.

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

Extract and Compile Nagios

tar xvf nagios-4.4.6.tar.gz
cd nagios-4.4.6
./configure --with-command-group=nagcmd
make all
sudo make install
sudo make install-commandmode
sudo make install-init

Create Nagios User and Group

sudo useradd nagios
sudo groupadd nagcmd
sudo usermod -a -G nagcmd nagios
sudo usermod -a -G nagcmd www

Install Nagios Plugins

cd /tmp
wget https://nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz
tar xvzf nagios-plugins-2.3.3.tar.gz
cd nagios-plugins-2.3.3
./configure --with-nagios-user=nagios --with-nagios-group=nagios
make
sudo make install

Configure Nagios

sudo vi /usr/local/nagios/etc/nagios.cfg

Uncomment the following lines:

#cfg_dir=/usr/local/nagios/etc/servers
#cfg_file=/usr/local/nagios/etc/commands.cfg

Save and close the file.

sudo mkdir /usr/local/nagios/etc/servers
sudo vi /usr/local/nagios/etc/objects/contacts.cfg

Replace the default email with your email address:

define contact{
    contact_name                    nagiosadmin             ; Short name of user
    use                             generic-contact         ; Inherit default values from generic-contact template
    alias                           Nagios Admin            ; Full name of user
    email                           nagios@localhost        ; <<***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
    }

Save and close the file.

sudo vi /usr/local/nagios/etc/objects/localhost.cfg

Replace the check_command line with the following:

check_command check-host-alive

Add the following lines at the end of the file:

define service{
    use                             local-service         ; Name of service template to use
    host_name                       localhost
    service_description             PING
    check_command                   check_ping!100.0,20%!500.0,60%
    }

define service{
    use                             local-service         ; Name of service template to use
    host_name                       localhost
    service_description             SSH
    check_command                   check_ssh
    notifications_enabled           0
    }

Save and close the file.

Verify Nagios Configurations

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

If you encounter any errors, fix them before proceeding.

Start Nagios Service

sudo rcctl enable nagios
sudo rcctl start nagios

Now, Nagios is installed and running on OpenBSD. You can access the web interface by navigating to http://<your-IP-address>/nagios. The default username and password are nagiosadmin and nagios, respectively.

Next, you can start adding hosts, services, and other network devices to monitor via the Nagios web interface.

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