Nagios 4 is a powerful enterprise-grade website monitoring platform that allows you to monitor every aspect of your website infrastructure – servers, network, websites, hardware and more. Let us look at how to install Nagios 4 in CentOS, RHEL, Fedora systems.
How to Install Nagios 4 in CentOS, RHEL, Fedora
Here are the steps to install Nagios 4 in CentOS, RHEL, Fedora. We will be installing Nagios 4.3.4 and Nagios Plugin 2.2.1
- You will find Nagios is installed at /usr/local/nagios directory
- You can access Nagios admin at http://localhost/nagios
1. Install Required Dependencies
Before we install Nagios, we need to install Apache, PHP and libraries like gcc, glibc, glibc-common and GD to ensure that your installation goes smoothly. If you don’t install them, Nagios will automatically install them for you.
$ yum install -y httpd httpd-tools php gcc glibc glibc-common gd gd-devel make net-snmp
Fedora 22+ onwards:
$ dnf install -y httpd httpd-tools php gcc glibc glibc-common gd gd-devel make net-snmp
2. Create Nagios User group
Next, we create a new user “nagios”, a new group “nagcmd” and set its password.
$ useradd nagios $ groupadd nagcmd
Next, we add both apache and nagios users to the new group.
$ usermod -G nagcmd nagios $ usermod -G nagcmd apache
3. Download installation files
Next, we create a directory where we will download and install Nagios Core and Plugin files
$ mkdir /root/nagios $ cd /root/nagios
Download Nagios Core and Plugin files
$ wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.3.4.tar.gz $ wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
If you want to download a different version, please update the above file names accordingly.
4. Extract the downloaded files
You can extract Nagios Core and plugin files with the commands
$ tar -xvf nagios-4.3.4.tar.gz $ tar -xvf nagios-plugins-2.2.1.tar.gz
If you have downloaded a different version, please update the above file names accordingly. After you extract these files, you will see that 2 new subfolders have been created in your present location (/root/nagios)
5. Install Nagios 4
You can install Nagios 4 by running the following commands
$ cd nagios-4.3.4 $ ./configure --with-command-group=nagcmd $ make all $ make install $ make install-init $ make install-config $ make install-commandmode
Then run the following command to configure Apache for Nagios
$ make install-webconf
6. Configure Apache Authentication
Next, we need to setup Apache authentication for the user “nagiosadmin”. Don’t use a different username. Run the following command
$ htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
You’ll be asked to enter a password twice. Remember it because you will need this username & password to log into Nagios web interface.
Restart Apache to apply changes
On RHEL/CentOS 6/5 and Fedora:
$ service httpd start
On RHEL/CentOS 7 and Fedora 19 Onwards:
$ systemctl start httpd.service
7. Install Nagios Plugins
Go to /root/nagios and install Nagios Plugins
$ cd /root/nagios $ cd nagios-plugins-2.2.1/ $ ./configure --with-nagios-user=nagios --with-nagios-group=nagios $ make $ make install
8. Verify Installation
You can verify that everything has been installed properly, by running the following command
$ /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
If you don’t see any errors in the output, you will see the following message at the end of the output
Total Warnings: 0 Total Errors: 0 Things look okay - No serious problems were detected during the pre-flight check
9. Restart Nagios
Add Nagios to system startup with the following commands
On RHEL/CentOS 6/5 and Fedora
$ chkconfig --add nagios $ chkconfig --level 35 nagios on $ chkconfig --add httpd $ chkconfig --level 35 httpd on
On RHEL/CentOS 7 and Fedora 19-26
$ systemctl enable nagios $ systemctl enable httpd
Restart Nagios to make the new settings take effect.
On RHEL/CentOS 6/5 and Fedora
$ service nagios start
On RHEL/CentOS 7 and Fedora 19-24
$ systemctl start nagios.service
10. View Nagios Web Interface
Open web browser and go to http://localhost/nagios. If you have installed it on your domain, go to http://your_domain/nagios
You will be asked for the username password. Enter username as “nagiosadmin” and password as the one you saved in step 6.
You will be directed to the Admin screen