Today's Offer - DevOps Certification Training - Enroll at Flat 10% Off.

- DevOps Blogs -

What is Nagios? Nagios Configure & Install Tutorial Guide for Beginner

As you browse sites for Nagios, there are only a few websites that have given information on this wonderful monitoring tool. So, I believe that this post would be a clear idea of what are Nagios, configuration, installation, and continuous monitoring with the Nagios. The tool keeps a close eye on your entire IT infrastructure, services, business processes, and the servers etc.

The main highlight of this post includes –

  • What is Continuous Monitoring?
  • Why we need Continuous Monitoring?
  • What is Nagios?
  • Nagios Architecture
  • Nagios Installing Tutorial Guide
  • Nagios configuration Tutorial Guide

Let us give a quick start to this blog by discussing on continuous monitoring concept and why we need it. Then we will discuss what is Nagios, Nagios installing & configuration tutorial guide for the beginners.

What is Continuous Monitoring?

Once the application is deployed to the server, the role of continuous monitoring comes into existence. The process is all about taking care of Company infrastructure and respond immediately as soon as some error occurs. The concept is not new but it is around for a long time.

SQL Server Curriculum

The technique you must have heard about is the static analysis that is responsible to detect, respond or report the logs but the analysis is not so much accurate as expected by the organizations. With the Continuous monitoring, you can perform and respond each of the activities in the best possible way.

Read: DevOps Engineer Job Description - Role & Responsibilities

When we discuss the continuous monitoring, this is necessary that all pieces of information should be connected well like database, warehouse, security tools, security management system, AI, security intelligence, data analytics etc. Connecting different pieces together in a well-organized manner is the crux of the process that makes the continuous monitoring more successful and useful requirement by the organizations?

Further, the process is performed on the continuous (on-going) basis that reports immediately about the risks that can be faced by Company for its poor infrastructure. You can also check the behavior of networks and data analytics report when required. According to a saying, if you cannot ‘measure’ the risks how will you ‘manage’ them and continuous monitoring is the solution that works best here.

Why is Continuous Monitoring useful?

Continuous Monitoring has the capability to detect the system errors before they could have negative impacts on your business productivity. Here, is a quick list of features that explain to you why continuous monitoring is useful –

  • The process helps in detecting network errors or server crashes.
  • With CM, you can detect or report any type of infrastructure issues quickly.
  • It also helps in maintaining security issues and service availability.
  • You can troubleshoot or monitor the performance issues of the server.
  • The process gives you a perfect idea of infrastructure upgrades, how can you make it even better that suits Company needs.
  • The process has the capability of reporting issues at first glance only.
  • The issues can be fixed automatically as soon as they are identified during the monitoring process.
  • On successful completion of continuous monitoring, it makes sure that it does not have any negative impact on your Company infrastructure and business operations.
  • The entire business process and IT infrastructure can be monitored in a single pass only.

What is Nagios?

Nagios is useful for continuous monitoring of applications, servers, or business processes etc. inside a DevOps culture. It gives information to the technical staff about any performance issues or drawbacks in the system. When you use Nagios, you don’t have to give much explanation how an unseen defect in the infrastructure can affect your organizational health badly. Nagios Tutorial Guide Consider the diagram given above to get a clear idea of Nagios working –

Nagios is running on a server where plug-ins is installed and running automatically. They further contact the hosts/servers on your network and give you the status message in two different forms – one is Web Interface and the other is SMS or E-mail. Further, Nagios Server as shown in the diagram earlier works as a scheduler and runs selected scripts after a repeated time interval. As soon as the requirement changes, the previous scripts will be stored and new scripts will run based on needs. In brief, Nagios working is based on Plug-ins that gives the confirm status of server, application, or infrastructure issues.

Read: What is Puppet? Puppet Tutorial Guide for Beginners

Nagios Infrastructure

The Nagios platform is based on the server-agent architecture. Take an example where Nagios is usually running over a host and plugins are designed to interact with the local network that should be monitored. Further, plug-ins send useful information to the scheduler that will be displayed over GUI. Nagios Tutorial Guide You also need to understand the working of NRPE – Nagios Remote plug-in Executor. With the NRPE, the plug-ins are executed over local servers or Linux machines. The objective of NRPE is to closely monitor the local resources over a remote resource. Nagios Tutorial Guide As per the rule, these resources should not be exposed to the external machines. This is the reason why NRPE is needed along with other important components. You can better understand the working of NRPE by looking at the diagram below –

  • Check_NRPE is a plugin that is available on local monitoring machine.
  • The NRPE daemon runs over the remote machine or Linux server and further monitors the resources and services for local and other hosts.
  • As you can see, there is one secure SSL connection between monitoring host and the remote/Linux host that is shown by the yellow arrow in the diagram.

Let us have some hands-on practice by this quick tutorial i.e. Nagios Installation and Configuration.

Nagios Installation and Configuration Tutorial Guide

Step 1 – Pre-requisites

Visit the URL - Nagios Tutorial Guide As you soon, you browse the link, the following web page will display in front of you. Here, you can have to click on i386 and you will be redirected to the following page. Nagios Tutorial Guide Here you can see the link “epel-release-6-8.noarch.rpm”, now open the terminal and copy the location of the link over the terminal. This is the way how you can download the repository on your system. SO, you are done with the first step that was pre-requisites. Let us move to the second step now.

SQL Server Quiz

Step 2 – Installing Nagios, Nagios Plugins, and NRPE

Execute the following command on the terminal to install, Nagios plug-ins and NRPE (Nagios Resource Plug-in Executor), Apache and PHP. Apache is needed to monitor the recent web server status and PHP is required to process the dynamic content on your website. Nagios Tutorial Guide In the next step, you should enable the Apache server with ‘chkconfig’ command as shown below in the screenshot. And once it is enabled start the Nagios and the Apache server with the ‘service’ command given below. Nagios Tutorial Guide Now create the swap file and avail minimum 1 GB space with the ‘dd’ command as given below – Nagios Tutorial Guide With the swap file, you can free up necessary space and shift it somewhere else to the hard drive. You can use “mkwsap” command to create the swap partitions and prepare the remote host for a swap area. The final command should be written like this as shown below – Nagios Tutorial Guide With the above command, only a temporary swap file is created. You can make the swap area permanent by adding it to the fstab file. Nagios Tutorial Guide With this command, we are done with the second step. Now let us move to the third step i.e. how to configure Nagios to access the Web interface.

Step 3 – Configure Nagios to access the Web Interface

At this step, you need to first set the password for web interface by typing the following command over terminal – Nagios Tutorial Guide Retype the password to confirm it. Now open the web browser and type the local hostname in the address bar.  Here, you need to enter the username and the password that is just given by you. By default, the username is Nagios admin. You can change the username in the advanced settings option. Password would the same that we set earlier. In the end, press OK. It will show Nagios dashboard in front of you as shown below. Nagios Tutorial Guide With these steps, you can monitor localhost only. If you are interested in monitoring the remote host then you need to install the NRPE.

Read: What is Vagrant? Vagrant Tutorial Guide for Beginners

Final Words:

With this Nagios Tutorial, we got the basic understanding of what is Nagios, about continuous monitoring, Nagios architecture, Nagios installation and its configuration. I am sure you must have enjoyed reading this blog and got something really new that was needed by you.

SQL Server training

To know more about Nagios, you should join DevOps certification program at JanBask Training and prepare yourself for a better future and wider job opportunities across the global marketplace.

Learn DevOps Related Topics.

    Janbask Training

    A dynamic, highly professional, and a global online training course provider committed to propelling the next generation of technology learners with a whole new way of training experience.

Trending Courses


  • AWS & Fundamentals of Linux
  • Amazon Simple Storage Service
  • Elastic Compute Cloud
  • Databases Overview & Amazon Route 53

Upcoming Class

5 days 02 Feb 2020


  • Intro to DevOps
  • GIT and Maven
  • Jenkins & Ansible
  • Docker and Cloud Computing

Upcoming Class

-1 day 27 Jan 2020

Data Science

  • Data Science Introduction
  • Hadoop and Spark Overview
  • Python & Intro to R Programming
  • Machine Learning

Upcoming Class

6 days 03 Feb 2020


  • Architecture, HDFS & MapReduce
  • Unix Shell & Apache Pig Installation
  • HIVE Installation & User-Defined Functions
  • SQOOP & Hbase Installation

Upcoming Class

7 days 04 Feb 2020


  • Salesforce Configuration Introduction
  • Security & Automation Process
  • Sales & Service Cloud
  • Apex Programming, SOQL & SOSL

Upcoming Class

0 day 28 Jan 2020


  • Introduction and Software Testing
  • Software Test Life Cycle
  • Automation Testing and API Testing
  • Selenium framework development using Testing

Upcoming Class

-1 day 27 Jan 2020

Business Analyst

  • BA & Stakeholders Overview
  • BPMN, Requirement Elicitation
  • BA Tools & Design Documents
  • Enterprise Analysis, Agile & Scrum

Upcoming Class

-1 day 27 Jan 2020

SQL Server

  • Introduction & Database Query
  • Programming, Indexes & System Functions
  • SSIS Package Development Procedures
  • SSRS Report Design

Upcoming Class

3 days 31 Jan 2020


Search Posts


Receive Latest Materials and Offers on DevOps Course