Nagios Monitoring Tool.

Nagios is a network monitoring tool designed with scalability and flexibility. Nagios is a free powerful open source monitoring tool that provides instant alert so can be fixed quickly. Nagios was designed for Linux operating systems, but it will also work under Unix-based systems. Nagios monitors all the resources such as memory usage, disk usage, load on processor, currently running processes and log files. And it also monitors the services on server such as SMTP, HTTP, IMAP, POP, etc. The Nagios monitoring tool provides a user-friendly Web-based graphical user interface. It also provides an authorization system for administrator to restrict the access. Nagios has proven popular among small business, educational institution, government agencies, health care institutions, etc.

 

Advantages of Nagios

1) Enhanced Auto Discovery Features.

2) Determine unresponsive machine and alert staff immediately.

3) Comprehensive Reports.

4) Increased server, services, and application availability.

5) Fast detection of network outages and protocol failures.

 

Nagios Dependencies

Initially install all the dependencies of Nagios monitoring tool to avoid errors while the installation steps. You can install all the dependencies using yum package manager.

# yum install gd gd-devel httpd php gcc glibc glibc-common openssl

 

System Information

Operating System: CentOS 6.4

Arch: x86_64

Nagios Version: 3.5.0

My Server IP address: 192.168.56.101

 

Pre-installation steps

Before starting the installation of Nagios on your server, we have to done some steps.

1) Login as root user to system. And install Epel repository rpm with the below command.

# wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

# rpm -ivh epel-release-6-8.noarch.rpm

 

2) Disable SELinux on the system.

# vim /etc/sysconfig/selinux

Change SELINUX=enforcing to SELINUX=disabled.

Also stop firewall iptables service.

# /etc/init.d/iptables stop

 

Installation steps

1) Install the Nagios monitoring tool by using yum package manager.

# yum install nagios nagios-devel nagios-plugins*

 

2) By default, yum install Nagios, cgi.cfg file contains authorized username ‘nagiosadmin’ and for htpasswd file /etc/nagios/passwd file is used. Generate a password for the user nagiosadmin by using the below command. (by default, the user is nagiosadmin and the password is also nagiosadmin)

# htpasswd -c /etc/nagios/passwd nagiosadmin

GiveAlphanumericPassword

 

3) Check the /etc/nagios/cgi.cfg file for the given values.

# vi /etc/nagios/cgi.cfg

 

# AUTHENTICATION USAGE

use_authentication=1

 

# SYSTEM/PROCESS INFORMATION ACCESS

authorized_for_system_information=nagiosadmin

 

# CONFIGURATION INFORMATION ACCESS

authorized_for_configuration_information=nagiosadmin

 

# SYSTEM/PROCESS COMMAND ACCESS

authorized_for_system_commands=nagiosadmin

 

# GLOBAL HOST/SERVICE VIEW ACCESS

authorized_for_all_services=nagiosadmin

authorized_for_all_hosts=nagiosadmin

 

# GLOBAL HOST/SERVICE COMMAND ACCESS

authorized_for_all_service_commands=nagiosadmin

authorized_for_all_host_commands=nagiosadmin

 

4) For accessing admin user through http, check the contents of nagios.conf file on /etc/httpd/conf.d/ directory. You can check it by using the below given command.

# cat /etc/httpd/conf.d/nagios.conf

 

5) Start the httpd service and nagios service by using the following commands.

# /etc/init.d/httpd start

# /etc/init.d/nagios start

You can access the Nagios monitoring tool via browser through the url:

http://nagios_server_ip-address/nagios

Provide the exact username=nagiosadmin and password to access the nagios tool.

 

If you need any further assistance please contact our support department.