Nagios is a free and powerful open source monitoring system that allows IT administrators to identify and resolve information system problems before they affect the services offered by this system. Nagios was launched in 1999 by Ethan Galstad and today it is officially sponsored by Nagios Enterprises.
The goal of using Nagios is to proactively monitor the IT department to ensure that the infrastructure, systems, applications, and services are working properly and are available to end users and customers. This allows technical teams to make decisions to solve problems before they escalate.
By using Nagios, you can :
.Supervise the entire IT infrastructure.
.Monitor the applications and services offered by the company.
.Plan infrastructure improvements before a problem is generated.
.Ensuring that SLAs signed with customers are respected.
.Reduce downtime, unavailability and loss of business.
.Learn about problems before they happen.
.Detect flaws and security issues.
.Guarantee maximum quality of service to customers.
Although the use of a supervisory tool like Nagios may seem vital and indispensable for managing an information system made up of several machines of different types, Nagios has a simple, understandable and three-element architecture :
.A task scheduler
.Programs to run to collect information
.A web interface to visualize in real time the machine states
In order for Nagios to fully meet expectations, it must rely on external programs called plugins to monitor machines connected to the network. Without these plugins, Nagios has no internal means to monitor equipment and collect information. Nagios is considered a scheduler of tasks and events. Its operating principle is quite simple: at any given moment, Nagios executes the plugins to collect information about the states of the machines.