NAGIOS

To install the nagios core :-

Make the repo

Then, check the ping

user

# useradd nagios

# wget -o nagioscore.tar.gz https://github.com/NagiosEnterprises/nagioscore/archive/nagios-4.5.8.tar.gz

# tar -xvf nagioscore.tar.gz

# groupadd nagcmd

# usermod -aG nagcmd nagios

# cd nagioscore-nagios-4.5.8

# ./configure

# make all

# make install

# make install-init

# make install-commandmode

# make install-config

# make install-webconf

# cd /

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

# systemctl enable –now httpd

# systemctl enable –now nagios

# firewall-cmd --permanent --add-service=http

# firewall-cmd –reloadfirew interface :-

http://<ip of nagios server>/nagios

To install plugins :-

# wget -o http://nagios-plugins.org/download/nagios-plugins-2.4.12.tar.gz

# cd nagios-plugins-2.4.12

# ./configure

# make all

# make install
 NAGIOS
# cd /

# cd /usr/local/nagios/libexec ( some files comes in to this file so my plugins have been done)

# cd /

# systemctl restart nagios

# systemctl restart httpd

Then check on browser

http://<ip of server>/nagios

( then services will be up)

Client Machine :- { to install the plugins}

# wget https:/wh/github.com/nagios-plugins/nagios-plugins/releases/download/release-2.4.12/nagios-plugins-
2.4.12.tar.gz

# yum install gcc glibc glibc-common make php gd gd-devel wget net-snmp openssl-devel

# useradd nagiosuser

# tar xvf nagios-plugins-2.4.12

# cd /nagios-plugins-2.4.12

# ./configure

# make all

# make install

#cd /usr/local/nagios/

#cd libexec ( some files will be come in this like green colour)

To install the nrpe for adding host :-

ma

lsls

# cd /nrpe-4.1.1/

# ./configure

# mak

# make install

# make install-init

# make install-config

# vim /usr/local/nagios/libexec/check_nrpe -H 192.168.1.212 -c check_users ( check the connectivity

Cd /
 NAGIOS
# vim /usr/local/nagios/etc/nrpe.cfg ( this is the main file)

Mention the ip entries of nagios server)

Allowed_hosts = <ip of server>

# systemctl enable –now nrpe

# firewall-cmd –permanent –add-service=nrpe

# firewall-cmd --reload

# netstat -ntulp | grep “5666”

fi

Server side :-

# wget https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-4.1.1/nrpe-4.1.1.tar.gz

# tar xvf nrpe-4.1.1.tar.gz

# cd nrpe-4.1.1/

# ./configure

# make all

# make install

#make install-init

# make install-config

# cd /

# vim /usr/local/nagios/etc/nrpe.cfg

( mention the ip address of nagios server )

# systemcl enable –now nrpe

# firewall-cmd –permanent –add-service=nrpe

# firewall-cmd --reload

# vim /usr/local/nagios/etc/objects/192.168.1.212.cfg ( I make file within the object folder for add host or services )

# Default Linux Host Template ##

define host{

name linux-anjali ; Name of this template

use generic-host ; Inherit default values

check_period 24x7

check_interval 5

retry_interval 1
 NAGIOS
max_check_attempts 10

check_command check-host-alive

notification_period 24x7

notification_interval 30

notification_options d,r

contact_groups admins

register 0 ; DONT REGISTER THIS - ITS A TEMPLATE

## Default

define host{

use linux-anjali ; Inherit default values from a template

host_name anjali.example.com ; The name we're giving to this server

alias rhel8 ; A longer name for the server

address 192.168.1.94 ; IP address of Remote Linux host

Save &exit this file

# vim /usr/local/nagios/etc/objects/services.cfg

define service {

use local-service ; Name of service template to use

host_name anjali.example.com

service_description Root Partition

check_command check_local_disk!20%!10%!/

# Define a service to check the number of currently logged in

# users on the local machine. Warning if > 20 users, critical

# if > 50 users.

define service {
 NAGIOS

use local-service ; Name of service template to use

host_name anjali.example.com

service_description Current Users

check_command check_local_users!20!50

# Define a service to check the number of currently running procs

# on the local machine. Warning if > 250 processes, critical if

# > 400 processes.

define service {

use local-service ; Name of service template to use

host_name anjali.example.com

service_description Total Processes

check_command check_local_procs!250!400!RSZDT

# Define a service to check the load on the local machine.

define service {

use local-service ; Name of service template to use

host_name anjali.example.com

service_description Current Load

check_command check_local_load!5.0,4.0,3.0!10.0,6.0,4.0

}
 NAGIOS

# Define a service to check the swap usage the local machine.

# Critical if less than 10% of swap is free, warning if less than 20% is free

define service {

use local-service ; Name of service template to use

host_name anjali.example.com

service_description Swap Usage

check_command check_local_swap!20%!10%

# Define a service to check SSH on the local machine.

# Disable notifications for this service by default, as not all users may have SSH enabled.

define service {

use local-service ; Name of service template to use

host_name anjali.example.com

service_description SSH

check_command check_ssh

notifications_enabled 0

# Define a service to check HTTP on the local machine.

# Disable notifications for this service by default, as not all users may have HTTP enabled.

define service {

use local-service ; Name of service template to use

service_description HTTP

check_command check_http

notifications_enabled 0

Save & exit this file

# vim /usr/local/nagios/etc/objects/command.cfg

Line no 231

v# systemctl restart nagios

# systemctl restart http

# systemctl restart nagios

# vim /usr/local/nagios/etc/nagios.cfg

Mention the some entries 35

Cfg_file=/usr/local/nagios/etc/objects/192.168.1.212.cfg

Cfg_file=/usr/local/nagios/etc/objects/service.cfg

Save & exit this file

# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg ( check the error of vim

# systemctl enable –now nrpe

# systemctl restart nagios# systemctl restart nrpe

# systemctl restart httpd

then, check the browser