Nagios Monitoring Tool.
Posted on January 28th, 2017
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.
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
Operating System: CentOS 6.4
Nagios Version: 3.5.0
My Server IP address: 192.168.56.101
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.
# 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
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
3) Check the /etc/nagios/cgi.cfg file for the given values.
# vi /etc/nagios/cgi.cfg
# AUTHENTICATION USAGE
# SYSTEM/PROCESS INFORMATION ACCESS
# CONFIGURATION INFORMATION ACCESS
# SYSTEM/PROCESS COMMAND ACCESS
# GLOBAL HOST/SERVICE VIEW ACCESS
# GLOBAL HOST/SERVICE COMMAND ACCESS
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:
Provide the exact username=nagiosadmin and password to access the nagios tool.
If you need any further assistance please contact our support department.