Preamble
In this guide we will install Nagios 4 on Debian 11 / Debian 10 Linux. Nagios is a powerful monitoring system that enables organizations to identify and resolve IT infrastructure problems before they affect critical business processes. It monitors your entire IT infrastructure to ensure systems, applications, services, and business processes are functioning properly. In the event of a failure, Nagios can alert the technical staff of the problem, allowing them to begin remediation processes before outages affect business processes, end-users, or customers.
Nagios® Core™ is an Open Source system and network monitoring application. It watches hosts and services that you specify, alerting you when things go bad and when they get better.
If you would wish to install Nagios Core on Debian 11 / Debian 10, the following steps will help you rev it up in a few minutes.
Step 1: Update your System
Run the command below to update your server so that we begin from latest software installed
sudo apt update && sudo apt -y full-upgrade
[ -f /var/run/reboot-required ] && sudo reboot -fIf it is a totally new server, follow this guide to update your apt sources file (/etc/apt/sources.list)
Step 2: Install the required packages
The following step will install the pre-requisite packages that Nagios Core needs to run. Please proceed to install them.
sudo apt install vim wget curl build-essential unzip openssl libssl-dev apache2 php libapache2-mod-php php-gd libgd-devStep 3: Fetch and extract Nagios Files
We now have to go to the Nagios downloads page to grab the latest release.
cd ~
NAGIOS_VER=$(curl -s https://api.github.com/repos/NagiosEnterprises/nagioscore/releases/latest|grep tag_name | cut -d '"' -f 4)
wget https://github.com/NagiosEnterprises/nagioscore/releases/download/$NAGIOS_VER/$NAGIOS_VER.tar.gzExtract the tarball
tar xvzf $NAGIOS_VER.tar.gzStep 4: Compile the extracted files
After Nagios core files have been successfully extracted, navigate into the new directory holding the files and begin the compilation process.
cd $NAGIOS_VER
./configure --with-httpd-conf=/etc/apache2/sites-enabledYou should see the following when the above command ends.
....
Creating sample config files in sample-config/ ...
*** Configuration summary for nagios 4.4.7 2022-04-14 ***:
General Options:
-------------------------
Nagios executable: nagios
Nagios user/group: nagios,nagios
Command user/group: nagios,nagios
Event Broker: yes
Install ${prefix}: /usr/local/nagios
Install ${includedir}: /usr/local/nagios/include/nagios
Lock file: /run/nagios.lock
Check result directory: /usr/local/nagios/var/spool/checkresults
Init directory: /lib/systemd/system
Apache conf.d directory: /etc/apache2/sites-enabled
Mail program: /bin/mail
Host OS: linux-gnu
IOBroker Method: epoll
Web Interface Options:
------------------------
HTML URL: http://localhost/nagios/
CGI URL: http://localhost/nagios/cgi-bin/
Traceroute (used by WAP):
Review the options above for accuracy. If they look okay,
type 'make all' to compile the main program and CGIs.Step 5: Create User And Group
This step ensures that “nagios” user and group are created. The www-data user is also added to the “nagios” group.
sudo make install-groups-users
sudo usermod -a -G nagios www-dataNow let us compile the main Nagios program and associated packages
sudo make allInstall the main program, CGIs, and HTML files
sudo make installStep 6: Install Daemon
This installs Nagios daemon files and also configures them to start when the system boots.
sudo make install-daemoninitStep 7: Add Command Mode
This installs and configures the external command file.
sudo make install-commandmodeStep 8: Install Configuration Files
In this step, we install SAMPLE configuration files required as Nagios needs some configuration files to allow it to start.
sudo make install-configStep 9: Apache Webserver Configuration
We have to configure our Apache to serve Nagios web pages. Nagios developers made it easier to set up Apache. You simply run one command to set up configuration files and then enable specific apache modules. Proceed as below.
This will install config files
sudo make install-webconfThis enables Apache rewrite and CGI modules
sudo a2enmod rewrite cgiStep 10: Configure Nagios Apache Authentication
In order to create Nagios Web authentication, you need to create a web user for authentication. The “htpasswd” command rises to the occasion for this task. Please note that Nagios uses “nagiosadmin” user by default. Run the command below and input your favorable password.
sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadminAfter that, give appropriate permissions to the (/usr/local/nagios/etc/htpasswd.users) file.
sudo chown www-data:www-data /usr/local/nagios/etc/htpasswd.users
sudo chmod 640 /usr/local/nagios/etc/htpasswd.usersStep 11: Install essential Nagios Plugins
Before we finish up setting up our Nagios core monitoring, we need Nagios Plugins that will help us accomplish a lot of stuff including monitoring the localhost. We will thus fetch the latest stable release of plugins, extract and install it in our system. You can find the plugins at Nagios Plugins. Follow along
Fetch and extract the plugins
cd ~VER=$(curl -s https://api.github.com/repos/nagios-plugins/nagios-plugins/releases/latest|grep tag_name | cut -d '"' -f 4|sed 's/release-//')
wget https://github.com/nagios-plugins/nagios-plugins/releases/download/release-$VER/nagios-plugins-$VER.tar.gz
tar xvf nagios-plugins-$VER.tar.gzNavigate into the new plugins folder then compile and install.
cd nagios-plugins-$VER
./configure --with-nagios-user=nagios --with-nagios-group=nagios
sudo make
sudo make installStep 12: Allow ports on the firewall and start Nagios
In case you have a firewall running, please allow the necessary ports.
sudo ufw allow 80
sudo ufw reloadStart Nagios and Apache services
sudo systemctl restart apache2
sudo systemctl start nagios.serviceStep 13: Log into Nagios Web Interface
After everything has been done well without any errors, let us open up our browser and get to see if the Nagios web interface is accessible. Open your browser and key in the IP of your server or its domain name if you had configured one and the root directory of Nagios.
http://<IP Address/FQDN>/nagiosYou will be prompted for a username and password. The username as you may remember is the one we set in Step 10, that is “nagiosadmin“
Provide credentials to access Nagios dashboard.
If you click on the “Hosts” link, you should see that the localhost is up and hence being monitored thanks to the plugins we installed earlier.
Conclusion
We hope this session was as informative and helpful as possible and we thank you for visiting. You make it all worthwhile. In case you are interested in other monitoring tools, the guides below will be great for you as well.
- How to Install Sensu Monitoring Tool on Ubuntu
- Install LibreNMS Monitoring Tool on CentOS with Letsencrypt and Nginx
- How To Install Icinga2 Monitoring Tool on Ubuntu
- Install Cacti Monitoring Server on Debian 10 (Buster) with Nginx
- Install and Configure Zabbix Server 4.4 on Debian 10 (Buster)
- How To Install Zabbix Agent on Debian
- How To Install Zabbix Server on CentOS 8 / RHEL 8
- How To Install Icinga2 Monitoring Tool on Ubuntu 18.04 LTS
