Nagios Installation Step by Step in Centos

Configuring and Installing Nagios Core 4 on CentOS 6 & 7

Step 1 > download the rpm in /tmp from epel


# wget  http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm      (64bit)

#wget  http://rpms.famillecollet.com/enterprise/remi-release-6.rpm    (64bit)

tmp]#ll -lrt  (you can see the Downloaded rpm)


now change the permission of epel rpm's

#chmod 755 /tmp/epel_press_tab

#chmod 755 /tmp/remi_press_tab

Now you check the permission and install the rpm

#ls -lrt /tmp

#rpm -ivh epel-release*

#rpm -ivh remi-release*

now install the Nagios, Nagios-plugin-all ,nrpe php, httpd


#yum install -y nagios nagios-plugins-all nagios-plugins-nrpe nrpe php httpd 


make sure iptables is off if on then add the following line in iptables

iptables -A INPUT  -m  state  --state NEW -m tcp -p tcp --dport 80  -j ACCEPT


#service iptables restart


now confgiure  the nagios contact file for alerts on email

#vim /etc/nagios/objects/contacts.cfg

go on line number 35

email         replace root@localhost to you email

email        techwithtechie@gmail.com    ;  <<******


:wq!  (Save and exit)


this is optional if you want to access nagios console from particular IP then u can configure


#vi  /etc/httpd/conf.d/nagios.conf


type after open the file   :se nu   (to see line numbers in vim )


after that uncomment the line number 15 and 16


# Order allow, deny
# Allow from all

uncoment both line and now go to the line number 17 18 and 19

# Order deny,allow
# Deny from all
# Allow from 127.0.0.1 10.91.142.101/23

uncomment the all three line

Order deny,allow
Deny from all
Allow from 127.0.0.1 10.91.142.101/23

Now set the password for nagiosadmin user

#htpasswd /etc/nagios/passwd  nagiosadmin
new-passwd:
Re-type-passwd:



Now start the Nagios and httpd services


#/etc/init.d/nagios  start
#/etc/init.d/httpd   start

#chkconfig nagios on
#chkconfig httpd on


now access Nagios Console url:

http://localhost/nagios

http://IP_Address_of_your_system/nagios

http://127.0.0.1/nagios/ 

enter the user name   nagios admin
enter Password what you have set.

Done.

might be someone face error like this

Forbidden

You don't have permission to access /nagios/cgi-bin//status.cgi on this server.
Apache/2.2.15 (CentOS) Server at 10.91.142.101 Port 80

that can be issue of ip conflict issue please set valid IP.

Thanks
Vijay Thakur