Install Nagios on Centos 5
Installing Nagios server and network monitoring on Centos 5 server
The official documentation can be found at http://support.nagios.com/knowledge-base/official-documentation
Install necessary packages
yum install httpd gcc glibc glibc-common gd gd-devel php
Create Nagios User account and group
useradd -m nagios
Create nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user
groupadd nagcmd usermod -a -G nagcmd nagios usermod -a -G nagcmd apache
Create Directory to store Nagios installation files
mkdir /opt/Nagios
Download Nagios and Plugins
Save file to directory /opt/Nagios
http://www.nagios.org/download/download.php
As of this writing Nagios 3.0.6 (Stable) and Nagios Plugins 1.4.13 (Stable)
Extract Files:
cd /opt/Nagios tar xzf nagios-3.0.6.tar.gz cd nagios-3.0.6
Compile and Configure Nagios
./configure --with-command-group=nagcmd
Compile Nagios:
make all
Compile binaries, init script, sample config files:
make install make install-init make install-config make install-commandmode
** Do Not Start Nagios **
Nagios has now been installed to the directory /usr/local/nagios/
Install Nagios Web Interface:
make install-webconf
Nagios Web Interface installed to /usr/local/nagios/share ( http conf file added to /etc/httpd/conf.d/nagios.conf )
Create Web Interface Login User:
** This is not the most secure method **
We will create user “nagiosadmin” ( remember the password you assign !)
htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Restart Apache:
service httpd restart
Install Nagios Plugins
Extract Files:
cd /opt/Nagios tar xzf nagios-plugins-1.4.13.tar.gz cd nagios-plugins1.4.13
Compile and Configure Nagios Plugins
./configure --with-nagios-user=nagios --with-nagios-group=nagios make make install
Configure nagiosadmin email address for alerts
vi /usr/local/nagios/etc/objects/contacts.cfg email nagios@localhost ; <<***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
Verify the sample Nagios configuration files
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg Total Warnings: 0 Total Errors: 0
Start Nagios
Enable Nagios to start at system startup / boot
chkconfig --add nagios chkconfig nagios on chkconfig httpd on
Start Nagios
service nagios start
Log into Web Interface
http://ip-address/nagios/



Great writeup! One additional would be to include php in your yum install line.
Thanks!
Thank Travis
Added php to yum install line
Hi
I do all you wrote, i get no errors but when i try to logging to the Nagios using the web i get 401 error , i use the user and pass i cretaed in the start.
any ideas?
401 is authorization error
issue with /usr/local/nagios/etc/htpasswd.users
Check permissions of htpasswd.users and also try again
htpasswd -c /usr/local/nagios/etc/htpasswd.users
It seems it is working so no it is time to play xD
Thanks a lot!!
How can i add host on nagios.. Here another problem when i browse like this http://10.156.0.36/nagios…that time when i click on host i saw an error.whats the reason
I got the same 401 error but I could navigate to the left pane menu.
to fix it i did
#su -l
#passwd nagios (reset the nagios password)
#getenforce
#setenforce 0
#chcon -R -t httpd_sys_content_t /usr/local/nagios/sbin/
#chcon -R -t httpd_sys_content_t /usr/local/nagios/share/
I was able to see the content in the right frame.
Hope this helps.
ciao
Nino