Hi,

Today I was hunting about monitoring tool in linux and found lots of monitoring tools (i.e. Nagios, openNMS, Cacti etc..) And I try to install nagios. You can also install nagios by following steps :-

Prerequisites:

1. Apache
2. PHP
3. GCC compiler
4. GD development libraries
5. PERL Modules
6. RRDTOOL

And you can install these packages through yum:-

[root@map007]# yum install httpd

[root@map007]# yum install php php-mysql php-gd php-ldap php-xml

[root@map007]# yum install gd  gd-devel

[root@map007]# yum install gcc  glibc  glibc-common libstdc++-devel gcc-c++

[root@map007]# yum install install perl-DBI perl-DBD-MySQL

[root@map007]# yum install install perl-Config-IniFiles

[root@map007]# yum install install rrdtool perl-rrdtool

Now create new nagios user account and give it password….

[root@map007]#  useradd  nagios

[root@map007]#   passwd nagios

Now create nagcmd group for external commands to be submitted through the web interface. Add both the nagios user and the apache user to the group.

[root@map007]# groupadd  nagcmd

[root@map007]# usermod –a –G  nagcmd nagios

[root@map007]# usermod –a –G nagcmd apache

Now download Nagios and Nagios-Plugins :-

[root@map007]# wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.2.1.tar.gz

[root@map007]# wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.11.tar.gz

[root@map007]# tar –zxvf nagios-3.2.1.tar.gz

[root@map007]#  cd  nagios-3.2.1

[root@map007]# ./configure  - -with-command-group=nagcmd

[root@map007]#  make all

[root@map007]#  make install

[root@map007]# make install-init

[root@map007]# make install-config

[root@map007]# make install-commandmode

[root@map007]# make install-webconf

(it will create nagios web config file in apache conf.d direcotry)

Now create nagiosadmin account for nagios web interface.

[root@map007]#  htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Password:

[root@map007]#  /etc/init.d/httpd  restart

Now install nagios-plugin.

[root@map007]# tar –zxvf nagios-plugins-1.4.11.tar.gz

[root@map007]# cd nagios-plugins-1.4.11

[root@map007]# ./configure  –with-nagios-user=nagios –with-nagio-group=nagios

[root@map007]# make

[root@map007]# make install

Now you have installed all the required packages and services.

Now start nagios.

[root@map007]#  chkconfig  –add nagios

[root@map007]#  chkconfig nagios on

Verify your nagios config file.

[root@map007]#  /usr/local/nagios/bin/nagios  -v  /usr/local/nagios/etc/nagios.cfg

If there is no error it means your nagios configuration is correct and you can start nagios service.

[root@map007]#  /etc/init.d/nagios  start

Now access your nagios web interface :-

http://localhost/nagios

==============================================

NRPE  Installation and Setup:-

Download and Install NRPE

You may download nrpe from http://www.nagios.org/download/download.php

[root@map007~]# wget http://prdownloads.sourceforge.net/sourceforge/nagios/nrpe-2.12.tar.gz

Extract the Files:

[root@map007~]# tar -xzf nrpe-2.12.tar.gz
[root@map007~]# cd nrpe-2.12

Compile and Configure NRPE

You need the openssl-devel package installed to compile NRPE with ssl support.  So make sure that open ssl is already installed on the server.

Install NRPE:

[root@map007~]# ./configure

General Options:

————————-
NRPE port: 5666
NRPE user: nagios
NRPE group: nagios
Nagios user: nagios
Nagios group: nagios

[root@map007~]# make all

[root@map007~]# make install-plugin

[root@map007~]# make install-daemon

[root@map007~]# make install-daemon-config

[root@map007~]# make install-xinetd

Post NRPE Configuration

Edit Xinetd NRPE entry:

Add Nagios Monitoring server to the “only_from” directive

[root@map007~]# vi /etc/xinetd.d/nrpe

Entry will be like this:-

service nrpe
{
flags           = REUSE
socket_type     = stream
port            = 5666
wait            = no
user            = nagios
group           = nagios
server          = /usr/local/nagios/bin/nrpe
server_args     = -c /etc/nrpe.conf –inetd
log_on_failure  += USERID
disable         = no
#       only_from       = 127.0.0.1
}

only_from = 127.0.0.1 <nagios_ip_address, replace the 127.0.0.1 with the nagios server ip or comment it>

Edit services file entry:

Add entry for nrpe daemon

[root@map007~]# vi /etc/services

nrpe 5666/tcp # NRPE

Restart Xinetd and Set to start at boot:

[root@map007~]# chkconfig xinetd on

[root@map007~]# service xinetd restart

Test NRPE Daemon Install

Check NRPE daemon is running and listening on port 5666:

[root@map007~]# netstat -at |grep nrpe

Output should be:-

tcp 0 0 *:nrpe *.* LISTEN

or

[root@map007]# netstat -plan | grep 5666

tcp        0      0 0.0.0.0:5666                0.0.0.0:*                   LISTEN      15721/xinetd

Check NRPE daemon is functioning:

[root@map007]# /usr/local/nagios/libexec/check_nrpe -H localhost

Output should be NRPE version:

NRPE v2.12

======================================================================

Enjoy Linux !!!