NAGIOS

                                      HOW TO INSTALL NAGIOS 
###############################################################


# yum install httpd
# yum install gcc
# yum install glibc glibc-common


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


# useradd nagios
# passwd nagios


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


# groupadd nagcmd
# usermod -G nagcmd nagios
# usermod -G nagcmd apache


3) Download Nagios and the Plugins


Create a directory for storing the downloads.


# mkdir /root/downloads
# cd /root/downloads


Download the source code tarballs of both Nagios and the Nagios plugins (visit http://www.nagios.org/download/ for links to the latest versions). IT's also present inftp://server1.example.com/upload


4) Compile and Install Nagios


Extract the Nagios source code tarball.


# cd /root/downloads
# tar xzf nagios-3.0a4.tar.gz
# cd nagios-3.0a4


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...


4) Customize Configuration


Sample configuration files have now been installed in the /usr/local/nagios/etc directory.


Edit the /usr/local/nagios/etc/objects/contacts.cfg config file  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


5) 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


6) Compile and Install the Nagios Plugins


Extract the Nagios plugins source code tarball.


# cd /root/downloads
# tar xzf nagios-plugins-1.4.7.tar.gz
# cd nagios-plugins-1.4.7


Compile and install the plugins.


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


7) 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) Modify SELinux Settings
See if SELinux is in Enforcing mode.


# getenforce


Put SELinux into Permissive mode.


# setenforce 0


To make this change permanent, you'll have to modify the settings in /etc/selinux/config and reboot.


Instead of disabling SELinux or setting it to permissive mode, you can use the following command to run the CGIs under SELinux enforcing/targeted mode:


# chcon -R -t httpd_sys_content_t /usr/local/nagios/sbin/
# chcon -R -t httpd_sys_content_t /usr/local/nagios/share/


9) 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/


############################# GOOD LUCK ##########################################