Nagios -Introduction

What is Continuous Monitoring?

Continuous monitoring is a process to detect, report, respond all the attacks which occur in its infrastructure. Once the application is deployed into the server, the role of continuous monitoring comes in to play. The entire process is all about taking care of the company's infrastructure and respond appropriately.

What is Nagios?

Nagios is a free-to-use open-source software tool for continuous monitoring. It helps you to monitor the system, network, and infrastructure. It is used for continuous monitoring of systems, applications, service, and business processes in a DevOps culture.

Nagios runs plugins stored on the same server. Plugin connects with a host or another server on your network or the Internet. Therefore, in the case of failure Nagios core can alert the technical staff about the issues. So that, your technical team performs the recovery process before outage in the business processes.

Why We Need Nagios?

1. Detects all types of network or server issues

2. Helps you to find the root cause of the problem which allows you to get the permanent solution to   e     problem

3. Active monitoring of your entire infrastructure and business processes

4. Allows you to monitors and troubleshoot server performance issues

5. Helps you to plan for infrastructure upgrades before outdated systems create failures

6. You can maintain the security and availability of the service

7. Automatically fix problems in a panic situation

Nagios Architecture

Nagios is a client-server architecture. Usually, on a network, a Nagios server is running on a host, and plugins are running on all the remote hosts which should be monitored.

 1. The scheduler is a component of server part of Nagios. It sends a signal to execute the plugins at the remote host.

2.  The plugin gets the status from the remote host

3.  The plugin sends the data to the process scheduler

4.  The process scheduler updates the GUI and notifications are sent to admins

Plugins:

Nagios plugins provide low-level intelligence on how to monitor anything and everything with Nagios Core. Plugins operate acts as a standalone application, but they are designed to be executed by Nagios Core. It connects to Apache that is controlled by CGI to display the result. Moreover, a database connected to Nagios to keep a log file.

How do plugins work?

• Check_nt is a plugin to monitor a windows machine which is mostly available in the monitoring server

• NSClinet++ should be installed in every Windows machine that you wants to monitor

• There is an SSL connection between the server and the host which continuously exchange information with each other

GUI:

An interface of Nagios is used to display in web pages generated by CGI. It can be buttons to green or red, sound, graph, etc.