How To Install Nagios 4.x Server/Client – Part 1

Nagios is an open-source tool for monitoring servers. when there is a good number of the server then health checks and server monitoring is a headache and Nagios is a good solution for such environment. It’s a lovely Open Source monitoring tool and always keep you updated about server health.

If you are using Nagios you can monitor server hosts on a single platform on your web browser. whenever there is a warning occurring (your setup limit), it shows the warning and sends it to you through mail/SMS accordingly. It helps us to reduce downtime and business losses.

This post will help and instruct you to install Nagios4.0.1 from source (tarball) on RHEL 7.x/6.x/5.x, CentOS 7.x/6.x/5.x and Fedora 24-19 distributions. And it is really easy to set up and 100% effective and time-saving.

Nagios: nagios-4.0.1 and nagios-plugins-1.5
Installation Directory: /usr/local/Nagios
Nagios will be accessible at http://IP/nagios or http://localhost/nagios
By default, Nagios Will monitor Your local machine (Disk Usage, CPU Load, Current Users, Total Processes, etc.)

Step 1: Install Required Packages For compilation

-------------- ON RHEL 7.x/6.x/5.x, CentOS 7.x/6.x/5.x --------------------
[[email protected]]# yum install -y httpd php gcc glibc glibc-common gd gd-devel make net-snmp
-------------- Fedora 24-19 distributions -------------- 
[[email protected]]# dnf install -y httpd php gcc glibc glibc-common gd gd-devel make net-snmp

Step 2: Create Nagios User and Group

Create a new Nagios user and nagcmd group account and set a password.

[[email protected]]# groupadd nagcmd
[[email protected]]# useradd -G nagcmd nagios
[[email protected]]# echo "Your Password" | passwd --stdin nagios
[[email protected]]# usermod -G nagcmd apache

Step 3: Download Nagios Core 4.4.3 and Nagios Plugin 2.2.1

[[email protected]]# mkdir /root/nagios; cd /root/nagios
[[email protected]]# wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.3.tar.gz
[[email protected]]# wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz

Step 4: Extract Nagios Core and its Plugins

[[email protected]]# tar -xvzf nagios-4.4.3.tar.gz;tar -xvzf nagios-plugins-2.2.1.tar.gz

After Successful Extraction, remove These files if you want to

[[email protected]]# rm -rf nagios-4.4.3.tar.gz nagios-plugins-2.2.1.tar.gz

And Your Directory Will look Like this

[[email protected] nagios]# ll
total 1952
drwxrwxr-x. 18 root root     4096 Aug 20  2015 nagios-4.0.1
drwxr-xr-x. 15 root root     4096 Aug  1 21:58 nagios-plugins-2.1.2

Step 5: Configure Nagios Core

[[email protected] nagios] cd nagios-4.4.3
[[email protected] nagios-4.4.3] ./configure --with-command-group=nagcmd

Sample Output

Creating sample config files in sample-config/ ...
*** Configuration summary for nagios 4.0.1 017-04-2017 ***:
General Options:
-------------------------
Nagios executable: nagios
Nagios user/group: nagios,nagios
Command user/group: nagios,nagcmd
Event Broker: yes
Install ${prefix}: /usr/local/nagios
Install ${includedir}: /usr/local/nagios/include/nagios
Lock file: ${prefix}/var/nagios.lock
Check result directory: ${prefix}/var/spool/checkresults
Init directory: /etc/rc.d/init.d
Apache conf.d directory: /etc/httpd/conf.d
Mail program: /bin/mail
Host OS: linux-gnu
IOBroker Method: epoll
Web Interface Options:
------------------------
HTML URL: http://localhost/nagios/
CGI URL: http://localhost/nagios/cgi-bin/
Traceroute (used by WAP): /usr/bin/traceroute
Review the options above for accuracy. If they look okay,
type 'make all' to compile the main program and CGIs.

Now Make Final Hit to make it small (do not forget I am putting semicolon)

[[email protected] nagios-4.4.3 ]# make all;make install;make install-init;make install-commandmode;
make install-config;make install-webconf

[[email protected] nagios-4.4.3 ]# vim /usr/local/nagios/etc/objects/contacts.cfg

Sample
###############################################################################
###############################################################################
#
# CONTACTS
#
###############################################################################
###############################################################################
# Just one contact defined by default - the Nagios admin (that's you)
# This contact definition inherits a lot of default values from the 'generic-contact'
# template which is defined elsewhere.
define contact{
contact_name nagiosadmin ; Short name of user
use generic-contact ; Inherit default values from generic-contact template (defined above)
alias Nagios Admin ; Full name of user
email [email protected],[email protected] ; *** CHANGE THIS TO YOUR EMAIL ADDRESS ****
}

[[email protected] nagios-4.4.3 ]# htpasswd -s -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
New password: 
Re-type new password:

[[email protected] ]# service httpd start

[[email protected]]# cd /root/nagios/nagios-plugins-2.2.1
[[email protected]]# ./configure --with-nagios-user=nagios --with-nagios-group=nagios
[[email protected]]# make;make install

[[email protected]]# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
[[email protected]]# chkconfig --add nagios
[[email protected]]# chkconfig --level 35 nagios on
[[email protected]]# chkconfig --add httpd
[[email protected]]# chkconfig --level 35 httpd on
[[email protected]]# service nagios start

[[email protected] nagios-plugins-2.2.1]# systemctl enable nagios
Created symlink from /etc/systemd/system/multi-user.target.wants/nagios.service to /usr/lib/systemd/system/nagios.service.
[[email protected] nagios-plugins-2.2.1]# systemctl start nagios
[[email protected] nagios-plugins-2.2.1]# systemctl start httpd
[[email protected] nagios-plugins-2.2.1]# systemctl enable httpd
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.