🕹️Install Nagios For Monitoring With a New EC2 Instance

Introduction

What is Nagios

Nagios is an open network monitoring system and application - sources created by Ethan Galstad. Nagios monitors hosts and predetermined service, and displays a warning when something bad happened to the Server – like the server went down. Nagios runs on the Linux operating system.

Nagios NMS Function

1. Host and Services Monitoring: Nagios can be used to monitor in real-time the status of a host (physical server or machine virtual) and services such as HTTP, SSH, SMTP, POP3 and others using plugins.

2. Notifications and Alerting: Customizable alerting and various notification delivery methods via email, SMS, and Other channels allow you to get information when problems occur.

3. Web Interface: Nagios provides a user-friendly web interface for configuration and monitoring.

4. Plugins Architecture: Allows you to carry out monitoring that adapts to a variety of applications IT architecture using plugins.

Advantages of NMS Nagios

1. Nagios is open source, which means it can be used for free.

2. Using a web interface, so it can be accessed easily and remotely from any location other.

3. Apart from monitoring network services (HTTP, FTP, etc.), Nagios can also monitor hosts resources (disk usage, memory usage, processes, log files, etc.)

4. Has a reporting feature via a web interface.

5. It has lots of plugins, so it adds more Nagios features complete compared to other NMS.

6. Supports the use of Google Maps.

7. Has a Schedule downtime feature, which is very necessary when the server is on maintenance or upgrade.

Disadvantages of Nagios NMS

• The learning curve is steep, learning to install and configure Nagios requires some effort (effort) and higher knowledge, compared to other monitoring tools. Lots of it The available configuration options and plugins can be confusing for beginners.

• Resource consumption, running many active checks will consume resources systems, especially in large environments. Proper resource management it is very important to ensure Nagios operates smoothly.

• Web Interface Limitations, Although the Nagios web interface is easy to use most tasks, some complex configurations may still require editing configuration file directly. This may be a challenge for users who inexperienced.

• Not able to generate history reports of bandwidth usage.

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Installation

Create New Security Group

Name    : SG-NMS-Nagios
VPC     : VPC-Jakarta
Inbound Rules :
    - SSH      | Custom : SG-BastionHost
    - HTTP     | Anywhere (IPv4)   |
    - HTTPS    | Anywhere (IPv4)   |
Outbound Rules :
    - All Trafic | Any Where (IPv4)

Edit Security Group (WebServer&Database)

add a new inbound rules

SG-WebServer

Name : SG-WebServer
VPC : VPC-Jakarta
Inbound Rules :
    - SSH | Custom : SG-BastionHost
    - HTTP | Any Where (IPv4)
    - HTTPS | Any Where (IPv4)
    - All Trafic | Custom : SG-NMS-Nagios
Outbound Rules : 
    - All Trafic | Any Where (IPv4)

Database

Name : SG-DBServer
VPC : VPC-Jakarta
Inbound Rules :
    - SSH | Custom : SG-BastionHost
    - HTTP | Any Where (IPv4)
    - HTTPS | Any Where (IPv4)
    - All Trafic | Custom : SG-NMS-Nagios
Outbound Rules : 
    - All Trafic | Any Where (IPv4)

Create New EC2

#Nagios#
Name & Tag : NMS-Nagios
OS : Debian 12
Instance type : t2.micro
Key pair : vockey (.pem)
Network Setting : klik Edit
	VPC = VPC-Jakarta
	Subnet = pub-subnet-jakarta
	Auto-assign public IP : enable
	Security Group : SG-NMS-Nagios
Storage / EBS : 10GB

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Instance	IP Public	IP Private
Bastion Host	34.207.160.104	10.10.1.7
Web Server	54.166.19.96	10.10.1.141
DBInstance	-	10.10.2.196
NMS-Nagios	3.89.232.111	10.10.1.229

Configuration

SSH to NMS-Nagios

cd Downloads/
ssh-agent bash
ssh-add labsuser.pem

ssh -A -i labsuser ubuntu@<ip-addr-pub-bastion>

ssh admin@<ip-addr-priv-nagios>

Installation

Nagios-Core

##Install pre-requisites##
apt update
apt-get install -y autoconf automake gcc libc6 libmcrypt-dev make libssl-dev wget unzip bc gawk dc build-essential snmp libnet-snmp-perl gettext libmariadb-dev apache2 php libapache2-mod-php8.2 fping libgd-dev openssl libgd-dev 

##Download the source##
cd /tmp
wget -O nagioscore.tar.gz https://github.com/NagiosEnterprises/nagioscore/archive/nagios-4.4.14.tar.gz
tar xzf nagioscore.tar.gz

##Compile##
cd /tmp/nagioscore-nagios-4.4.14/
./configure --with-httpd-conf=/etc/apache2/sites-enabled
make all

##Create user and group##
##user www-data is added to the Nagios group##
make install-groups-users
usermod -a -G nagios www-data

##Install binary##
##in this step the binary files, OGIs, and HTML are installed.##
make install

##Install service / daemon##
make install-daemoninit

##Install command mode##
make install-commandmode

##Install configuration files##
make install-config

##Install apache config files##
make install-webconf
a2enmod rewrite
a2enmod cgi
systemctl restart apache2

##Create a nagiosadmin user##
htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
##password : nagiosadmin##

##Start service web server apache2##
systemctl restart apache2.service

##Start service / daemon nagios##
systemctl start apache2
systemctl start nagios.service

Nagios Plugins

##intall pre-requisites
apt-get install -y autoconf gcc libc6 libmcrypt-dev make libssl-dev wget bc gawk dc build-essential snmp libnet-snmp-perl gettext

##Download the source
cd /tmp
wget --no-check-certificate -O nagios-plugins.tar.gz https://github.com/nagios-plugins/nagios-plugins/archive/release-2.4.6.tar.gz
tar zxf nagios-plugins.tar.gz

##Compile + install 
cd nagios-plugins-release-2.4.6/
./tools/setup
./configure
make
make install

##Install the check_nrpe Plugin
cd /tmp
wget --no-check-certificate -O nagios-nrpe.tar.gz  https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-4.1.0/nrpe-4.1.0.tar.gz
tar zxf nagios-nrpe.tar.gz

##configure and complie the check_nrpe
cd nrpe-4.1.0
./configure
make check_nrpe
make install-plugin

##Edit file nagios.cfg
cd /usr/local/nagios/etc
mkdir -p /usr/local/nagios/etc/servers

nano nagios.cfg
##delete the pound sign at 51 (CTRL + / = 51)
   #cfg_dir=/usr/local/nagios/etc/servers -> 
   cfg_dir=/usr/local/nagios/etc/servers

##Edit file contacts.cfg
##add admin email contact.
nano objects/contacts.cfg
   #example : [email protected]
     
##on the last line add the following script:
define command{
        command_name check_nrpe
        command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
}

##Test-plugins
##Stop & Start service nagios.
systemctl stop nagios.service
ssytemctl enable nagios.service
systemctl start nagios.service
systemctl restart nagios.service
systemctl status nagios.service

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Configuration is Completed

Open Browser

http://<ip-addr-pub-nagios>/nagios

username : nagiosadmin
password : nagiosadmin