In this tutorial, We are going to perform How to download and Install Nagios Core on CentOS 7 or any Cloud Instance like Amazon EC2, Azure VM, Google Compute Engine,etc. with preinstalled CentOS 7 Step by Step.
Table of Contents
Introduction
Nagios Core is free and open source monitoring tools which is used to monitor the System resources, applications ,Services, Databases and network devices such asRouters,switches,..etc.
Using Nagios Core we can monitor below resources and Network Ports.
Resources:
- CPU utilization
- Memory utilization
- Disk utilization
- Logged in users
- Running processes
- System Uptime
- Service states
- Swap utilization
Network Ports:
- HTTP
- FTP
- SSH
- SMTP
- Ping
- Bandwidth Latency
- Mysql
- IMAP
- POP3
- Tomcat
- PHP wrapper
- MySQL
Prerequisites
- CentOS 7 Server
- Preinstalled http
- 1 CPU and 2 GB RAM
- Firewall Ports 80,443,5666
Before installing Nagios, update the System and Install the below per-requisite packages .
$ sudo yum update $ sudo yum install -y gcc glibc glibc-common wget unzip httpd php gd gd-devel perl postfix
Install unzip packages if not installed
$ sudo yum install unzip
Disable SELinux
# sed -i 's/SELINUX=.*/SELINUX=disabled/g' /etc/selinux/config
OR
Set in permissive mode.
$ setenforce 0
Step 1: Create Nagios User and Group
Enter below command to create Nagios user and group and add www-data user to nagios group.
$ sudo useradd nagios $ sudo groupadd nagios $ sudo make install-groups-users $ sudo usermod -a -G nagios www-data
Step 2: Download and Install Nagios Core on CentOS 7
Here We are downloading Nagios Core 4.4.5 setup, To download latest version visit Officical Nagios Site
Navigate to /tmp directory
$ cd /tmp
Download and Extract the Nagios Core Setup
$ sudo wget -O nagioscore.tar.gz https://github.com/NagiosEnterprises/nagioscore/archive/nagios-4.4.5.tar.gz $ tar xzf nagioscore.tar.gz $ cd /tmp/nagioscore-nagios-4.4.5/
Compile the Nagios Core and Install
$ sudo ./configure --with-nagios-group=nagios --with-command-group=nagios --with-httpd_conf=/etc/apache2/sites-enabled/ $ sudo make all $ sudo make install $ sudo make install-daemoninit $ make install-commandmode
Step 3: Install and Configure Apache Files
Install and configure apache files using below commands,
$ sudo make install-webconf
Restart an Apache to take effect
$ sudo systemctl start httpd.service
Step 4: Create User Account to Access Nagios Web Interface
We have to create user in apache and set password. Enter below command for same.
$ sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Output:
$ sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin New password: Re-type new password: Adding password for user nagiosadmin
Step 5: Download and Install Nagios Plugins
Navigate to /tmp directory, Download the nagios core plugin and extract it as shown below
$ cd /tmp $ sudo wget --no-check-certificate -O nagios-plugins.tar.gz https://github.com/nagios-plugins/nagios-plugins/archive/release-2.2.1.tar.gz $ tar zxf nagios-plugins.tar.gz
Compile and install nagios core plugins,
$ cd /tmp/nagios-plugins-release-2.2.1/ $ sudo ./tools/setup $ sudo ./configure $ sudo make $ sudo make install
Step 6: Verify Nagios Configuration, Start Nagios and Enable
Verify the Nagios core configuration using below command,
$ sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Output:
$ sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg Nagios Core 4.4.5 Copyright (c) 2009-present Nagios Core Development Team and Community Contributors Copyright (c) 1999-2009 Ethan Galstad Last Modified: 2019-08-20 License: GPL Website: https://www.nagios.org Reading configuration data... Read main config file okay... Read object config files okay... Running pre-flight check on configuration data... Checking objects... Checked 8 services. Checked 1 hosts. Checked 1 host groups. Checked 0 service groups. Checked 1 contacts. Checked 1 contact groups. Checked 24 commands. Checked 5 time periods. Checked 0 host escalations. Checked 0 service escalations. Checking for circular paths... Checked 1 hosts Checked 0 service dependencies Checked 0 host dependencies Checked 5 timeperiods Checking global event handlers... Checking obsessive compulsive processor commands... Checking misc settings... Total Warnings: 0 Total Errors: 0 Things look okay - No serious problems were detected during the pre-flight check
To start Nagios Service
$ sudo systemctl start nagios
To enable nagios service at system startup
$ sudo systemctl enable nagios
Step 7: Configure Firewall
Allow http port to access Nagios web interface, if you are configuring Nagios on Cloud Instance allow 80 port in inbound rules.
$ sudo firewall-cmd --zone=public --add-port=80/tcp $ sudo firewall-cmd --zone=public --add-port=80/tcp --permanent
Reload the firewall settings to take effect
$ sudo firewall-cmd --reload
Step 8: Accessing Nagios Web Interface
To access nagios web interface, Open your favorite browser and type your server name or IP followed by nagios/
http://Server_IP/nagios
OR
http://Domain_Name/nagios
Once you hit above URL, Enter the credentials of “nagiosadmin” user and you will be redirected to nagios default page.
To Monitor the services. go to Current status -> Services at left pane as shown below
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https://support.nagios.com/kb/article/nagios-core-installing-nagios-core-from-source-96.html
