Install and Configure Nagios Server
Date Posted: 08-06-2017
Nagios is an open source monitor tool widely used to monitor client machines. Here, we are going to explain on how to install and configure nagios server.
Prerequisites:
- Centos 7.0 Server – In this post, we are using centos server 7.0. We can use Ubuntu host as well to install nagios server.
Implementation:
We assumes that this is a fresh centos server. Let’s start with disabling selinux.
setenforce 0
Disable selinux permanently.
vi /etc/selinux/config
SELINUX=disabled
Install dependencies.
yum install -y httpd php gcc glibc glibc-common gd gd-devel make net-snmp
Create a nagios user and group nagcmd
useradd nagios
groupadd nagcmd
Add the users nagios and apache to nagcmd
usermod -G nagcmd nagios
usermod -G nagcmd apache
Download the nagios-server and nagios-plugins
cd /usr/local/src/
wget https://sourceforge.net/projects/nagios/files/nagios-4.x/nagios-4.3.2/nagios-4.3.2.tar.gz
wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
Extract the files nagios-server file and nagios plugin file.
tar -xzf nagios-4.3.2.tar.gz
tar -xzf nagios-plugins-2.2.1.tar.gz
Change the directory.
cd nagios-4.3.2
Configure the nagios.
./configure --with-command-group=nagcmd
Make and make install.
make all
make install
Create init script and command mode
make install-init
make install-commandmode
Create nagios configuration
make install-config
The above command will create basic configuration file.
Configuring Nagios:
Open contacts.cfg and update the email address where we want to receive notification.
vi /usr/local/nagios/etc/objects/contacts.cfg
email nagios@domain.tld
Install web-conf
make install-webconf
Create a nagiosadmin user to maintain authentication page on nagios interface
htpasswd -s -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Enter the password and repeat the password.
Start the httpd service
service httpd start
Now, install the nagios plugin which we downloaded already.
cd /usr/local/src/nagios-plugins-2.2.1
Configure the plugins.
./configure --with-nagios-user=nagios --with-nagios-group=nagios
Make & Make install the configured plugin
make && make install
Enable both nagios and httpd service on startup.
systemctl enable nagios
systemctl enable httpd
Start the nagios service
service nagios start
Additional Information:
Now, we create a configuration directory for the client hosts.
mkdir /usr/local/nagios/etc/servers
Add the configuration directory nagios.cfg
vi /usr/local/nagios/etc/nagios.cfg
Uncomment the following line,
cfg_dir=/usr/local/nagios/etc/servers
Add the NRPE command_line to check remote hosts.
vi /usr/local/nagios/etc/objects/commands.cfg
###############################################################################
# NRPE CHECK COMMAND
#
# Command to use NRPE to check remote host systems
###############################################################################
define command{
command_name check_nrpe
command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
}
Verify the nagios configuration for syntax error.
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Restart the nagios service.
/etc/init.d/nagios restart
Access the nagios URL on the browser.
http://IPADDRESS/nagios
Enter the password which we created using htpasswd.