step by stepm Configuration of nagios monitoring tools

What is nagios

Nagios is a popular open source computer system and network monitoring software application. It watches hosts and services, alerting users when things go wrong and again when they get better.

Nagios functionalities

� Nagios® is an open source tool specially developed to monitor host and service and designed to

inform you of network incidents before your clients, end-users or managers do. It has been

designed to run under the Linux operating system, but works fine under operating system also

� Initially developed for servers and application monitoring, it is now widely used to monitor

networks availability. It is possible with the development of specific plugins around Nagios

process.

�

Nagios works with a set of “plugins” to provide local and remote service status. The monitoring

daemon runs intermittent checks on hosts and services you specify using external "plugins"

which return status information to Nagios.

� When incidents are detected, the daemon send notifications out to administrative contacts in a

variety of different ways (email, instant message, SMS, etc.). Current status information,historical logs, and reports can all be accessed via a Web browser.� Custom “plugins” are relatively easy to develop

� Different methods are provided for remote resource discovery

� Nagios is freely available from http://www.nagios.org

Some of the many features of Nagios include:

1) Monitoring of network services (SMTP, POP3, HTTP, NNTP, PING, etc.)

2) Monitoring of host resources (processor load, disk usage, etc.)

3) Simple plugin design that allows users to easily develop their own service checks

4) Parallelized service checks

5) Ability to define network host hierarchy using "parent" hosts, allowing detection of and distinction between hosts that are down and those that are unreachable

6) Contact notifications when service or host problems occur and get resolved (via email, pager, or user-defined method)

7) Ability to define event handlers to be run during service or host events for proactive problem resolution

8) Automatic log file rotation

9) Support for implementing redundant monitoring hosts

10) Optional web interface for viewing current network status, notification and problem history, log file, etc.

What You’ll End Up With

If you follow these instructions, here’s what you’ll end up with:

1) Nagios and the plugins will be installed underneath /usr/local/nagios

2. Nagios will be configured to monitor a few aspects of your local system (CPU load, disk usage, etc.)
3. The Nagios web interface will be accessible at http://localhost/nagios/

Prerequisites

During portions of the installation you’ll need to have root access to your machine.

Make sure you’ve installed the following packages on your Fedora installation before continuing.

1)Apache

2)PHP

3)GCC compiler

4)GD development libraries

You can use yum to install these packages by running the following commands (as root):

# yum install httpd php

# yum install gcc glibc glibc-common

# yum install gd gd-devel

1) Create Account Information Become the root user.

su -l

2) Create a new nagios user account and give it a password.

/usr/sbin/useradd -m nagios

passwd nagios

3) Create a new nagcmd group for allowing external commands to be submitted through the web interface. And Add both the nagios user and the apache user to the group.

/usr/sbin/groupadd nagcmd

/usr/sbin/usermod -a -G nagcmd nagios

/usr/sbin/usermod -a -G nagcmd apache

Installation

1) Download Nagios and the Plugins

Download the source code tarballs of both Nagios and the Nagios plugins (visit

http://www.nagios.org/download/ for links to the latest versions). These directions were tested with

Nagios 3.1.1 and Nagios Plugins 1.4.11.

2) Compile and Install Nagios

Extract the Nagios source code tarball.

# tar xzf nagios-3.2.0.tar.gz

# cd nagios-3.2.0

Run the Nagios configure script, passing the name of the group you created earlier like so:

# ./configure --with-command-group=nagcmd

Compile the Nagios source code.

# make all

Install binaries, init script, sample config files and set permissions on the external command directory.

# make install

# make install-init

# make install-config

# make install-commandmode

Don’t start Nagios yet - there’s still more that needs to be done...

3) Customize Configuration

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

4) Configure the Web Interface

Install the Nagios web config file in the Apache conf.d directory.

# make install-webconf

Create a nagiosadmin account for logging into the Nagios web interface. Remember the password you

assign to this account - you’ll need it later.

# htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Restart Apache to make the new settings take effect.

# service httpd restart

5) Compile and Install the Nagios Plugins

Extract the Nagios plugins source code tarball.

# tar xzf nagios-plugins-1.4.11.tar.gz

# cd nagios-plugins-1.4.11

Compile and install the plugins.

# ./configure --with-nagios-user=nagios --with-nagios-group=nagios

# make

# make install

6) Start Nagios

Add Nagios to the list of system services and have it automatically start when the system boots.

# chkconfig --add nagios

# chkconfig nagios on

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.

# service nagios start

8) Login to the Web Interface

You should now be able to access the Nagios web interface at the URL below. You’ll be prompted for the

username (nagiosadmin) and password you specified earlier.

http://localhost/nagios/

Click on the "Service Detail" navbar link to see details of what’s being monitored on your local machine.

It will take a few minutes for Nagios to check all the services associated with your machine, as the

checks are spread out over time.