Nagios is the most widely used open source monitoring tools which help us to monitor the services and application that run’s on Windows, Linux, Routers and other network devices.
With the help of Nagios you can monitor basic services and attributes. We can access the Nagios using web interface coming with the bundle and configuration need to be done on the file level.
Services List
This Tutorial describes how you can monitor “private” services and attributes of Linux/UNIX servers, such as:
Attributes
- CPU load
- Memory usage
- Disk usage
- Logged in users
- Running processes
- etc.
Private Services
- HTTP
- FTP
- SSH
- SMTP
- etc
Prerequisites
yum -y install httpd php gcc glibc glibc-common gd wget perl
useradd nagios groupadd nagcmd usermod -a -G nagcmd nagios usermod -a -G nagcmd apache
Install Nagios
Download latest Nagios Core.
cd /tmp/ wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.3.4.tar.gz tar -zxvf /tmp/nagios-4.3.4.tar.gz cd /tmp/nagios-4.3.4/
Compile and Install Nagios:
./configure --with-nagios-group=nagios --with-command-group=nagcmd make all make install make install-init make install-config make install-commandmode make install-webconf
Configure Nagios
Sample configuration files have now been installed in the /usr/local/nagios/etc directory. These sample files should work fine for getting started with Nagios. You’ll need to make just one change before you proceed…
Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you’d like to use for receiving alerts.
vi /usr/local/nagios/etc/objects/contacts.cfg
Change the Email address field to receive the notification.
define contact{
contact_name nagiosadmin ; Short name of user
use generic-contact ; Inherit default values from generic-contact template (defined above)
alias Nagios Admin ; Full name of user
email [email protected] ; <<***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
}
Configure Nagios Web Interface
Create a nagiosadmin account for logging into the Nagios web interface. Remember the password that you assign to this user – you’ll need it later.
htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Restart Apache to make the new settings take effect.
systemctl restart httpd systemctl enable httpd
Install Nagios Plugins
Download Nagios Plugins to /tmp directory.
cd /tmp wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz tar -zxvf /tmp/nagios-plugins-2.2.1.tar.gz cd /tmp/nagios-plugins-2.2.1/
Compile and install the plugins.
./configure --with-nagios-user=nagios --with-nagios-group=nagios make make install
Starting Nagios
Verify the sample Nagios configuration files.
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
If there are no errors, start Nagios.
/etc/init.d/nagios start chkconfig nagios on
Firewall
Allow Apache web server through the firewall.
firewall-cmd --permanent --add-port=80/tcp firewall-cmd --reload
Access Nagios Web Interface
Now access the Nagios web interface using the following URL. You’ll be prompted for the username (nagiosadmin) and password you specified earlier.
That’s All.
