Author:Badi Ul Zaman email:bnhashmi at wbitt dot com

Part I: Installing Nagios on CentOS 5.3

Step # 1 Checking for Prerequisites.

yum list installed | egrep 'httpd|gcc|glibc|glibc-common|gd|gd-devel'

compat-gcc-34.i386 3.4.6-4 installed

compat-gcc-34-c++.i386 3.4.6-4 installed

compat-gcc-34-g77.i386 3.4.6-4 installed

compat-glibc.i386 1:2.3.4-2.26 installed

compat-glibc-headers.i386 1:2.3.4-2.26 installed

compat-libgcc-296.i386 2.96-138 installed

gcc.i386 4.1.2-44.el5 installed

gcc-c++.i386 4.1.2-44.el5 installed

gcc-gfortran.i386 4.1.2-44.el5 installed

gcc-gnat.i386 4.1.2-44.el5 installed

gcc-java.i386 4.1.2-44.el5 installed

gcc-objc.i386 4.1.2-44.el5 installed

gd.i386 2.0.33-9.4.el5_1.1 installed

gd-devel.i386 2.0.33-9.4.el5_1.1 installed

gdb.i386 6.8-27.el5 installed

gdbm.i386 1.8.0-26.2.1 installed

gdbm-devel.i386 1.8.0-26.2.1 installed

gdk-pixbuf.i386 1:0.22.0-25.el5 installed

gdm.i386 1:2.16.0-47.el5.centos installed

glibc.i686 2.5-34 installed

glibc-common.i386 2.5-34 installed

glibc-devel.i386 2.5-34 installed

glibc-headers.i386 2.5-34 installed

httpd.i386 2.2.3-22.el5.centos installed

libgcc.i386 4.1.2-44.el5 installed

sysklogd.i386 1.4.1-44.el5 installed

Above output shows that required packages are installed on system. In the case the are not installed you can install them using your CentOS 5.3 DVD. If you want to install from CentOS 5.3 DVD you need to enable CentOS-Media.repo

Enabling CentOS-Media.repo

vim /etc/yum.repos.d/CentOS-Media.repo


This repo is used to mount the default locations for a CDROM / DVD on CentOS-5. You can use this repo and yum to install items directly off the DVD ISO that we release. To use this repo, put in your DVD and use it with the other repos too:

yum --enablerepo=c5-media [command]

or for ONLY the media repo, do this:

yum --disablerepo=\\\\\* --enablerepo=c5-media [command]


name=CentOS-$releasever - Media








Step # 2 Installing Prerequisites.

yum --disablerepo=\\\\\* --enablerepo=c5-media -y install httpd gcc glibc glibc-common gd gd-devel

Step # 3 Creating Users/Groups needed.

groupadd nagcmd

useradd -G nagcmd,apache nagios

id nagios

passwd nagios

Step # 4 Downloading Nagios & Plugins

mkdir /downloads

cd /downloads

wget -c

wget -c

Step # 5 Extracting Nagios tar ball.

tar zxvf nagios-3.1.2.tar.gz

cd nagios-3.1.2

Step # 6 running ./configure script.

./configure –with-command-group=nagcmd

Step # 7 compiling the source code.

make all

Step # 8 Installing Nagios binaries.

make install

Step # 9 Installing init script.

make install-init

Step # 10 Installing sample config files.

make install-config

Step # 11 setting permissions on the external command directory.

make install-commandmode

Step # 12 Updating contacts/groups information in contacts.cfg file.

vim /usr/local/nagios/etc/objects/contacts.cfg change email address of nagiosadmin user line 35 according to your requirements.

Step # 13 Installing web configuration.

make install-webconf

Step # 14 creating nagiosadmin user and setting password for web-interface.

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

Step # 15 Configuring, Restarting Apache Service and Adding to runlevel 35 .

vim /etc/httpd/conf/httpd.conf go to line 391 and add index.php chkconfig –level 35 httpd on service httpd restart

Step # 16 Compiling and installing Nagios plugins.

cd /downloads/ tar zxvf nagios-plugins-1.4.13.tar.gz cd nagios-plugins-1.4.13 ./configure –with-nagios-user=nagios –with-nagios-group=nagios make

make install

Step # 17 Verifying, restarting nagios service and Adding to runlevel 35 .

/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg chkconfig –level 35 nagios on Changing nagios user home directory to /usr/local/nagios usermod -d /usr/local/nagios/ nagios service nagios restart ps aux | grep nagios

Step # 18 Modifying SeLinux Setting for Nagios

chcon -R -t httpd\_sys\_content\_t /usr/local/nagios/sbin/

chcon -R -t httpd\_sys\_content\_t /usr/local/nagios/share/

Step # 19 Login to Web-Interface.


Step # 20 Check for Nagios Logs

tail -f /usr/local/nagios/var/nagios.log

Now we are done with Nagios Installation Part-I Alhamdulillah.