Nagios Core , formerly known as Nagios, is a free and

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...

software application Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...

that

monitors Monitor or monitor may refer to: Places * Monitor, Alberta * Monitor, Indiana, town in the United States * Monitor, Kentucky * Monitor, Oregon, unincorporated community in the United States * Monitor, Washington * Monitor, Logan County, West Vir ...

systems A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and express ...

networks Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

and infrastructure. Nagios offers monitoring and alerting services for servers, switches, applications and services. It alerts users when things go wrong and alerts them a second time when the problem has been resolved. Ethan Galstad and a group of developers originally wrote Nagios as ''NetSaint''. they actively maintain both the official and unofficial plugins. Nagios is a

recursive acronym A recursive acronym is an acronym that refers to itself, and appears most frequently in computer programming. The term was first used in print in 1979 in Douglas Hofstadter's book '' Gödel, Escher, Bach: An Eternal Golden Braid'', in which Hof ...

: "Nagios Ain't Gonna Insist On Sainthood" – "sainthood" makes reference to the original name ''NetSaint'', which changed in response to a legal challenge by owners of a similar trademark. "

Agios ''Agios'' ( el, Άγιος), plural ''Agioi'' (), transcribes masculine gender Greek words meaning ' sacred' or ' saint' (for example Agios Dimitrios, Agioi Anargyroi). It is frequently shortened in colloquial language to ''Ai'' (for example Ai ...

" (or "hagios") also transliterates the Greek word ''άγιος'', which means "saint". Nagios was originally designed to run under

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

, but it also runs on other

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

variants. It is

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

licensed under the terms of the

GNU General Public License The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the Four Freedoms (Free software), four freedoms to run, study, share, and modify the software. The license was th ...

version 2 as published by the

Free Software Foundation The Free Software Foundation (FSF) is a 501(c)#501(c)(3), 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support the free software movement, with the organization's preference for software being distributed ...

Nagios agents

NRPE

Nagios Remote Plugin Executor (NRPE) is a Nagios agent that allows remote system monitoring using scripts that are hosted on the remote systems. It allows for monitoring of resources such as disk usage, system load or the number of users currently logged in. Nagios periodically polls the agent on remote system using the check_nrpe plugin. NRPE allows you to remotely execute Nagios plugins on other Linux/Unix machines. This allows you to monitor remote

machine A machine is a physical system using Power (physics), power to apply Force, forces and control Motion, movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to na ...

metrics (disk usage, CPU load, etc.). NRPE can also communicate with some of the Windows agent add-ons, so you can execute scripts and check metrics on remote Windows machines, as well. As of 28 Jan 2020, NRPE has been deprecated.

NRDP

Nagios Remote Data Processor (NRDP) is a Nagios agent with a flexible data transport mechanism and processor. It is designed with an architecture that allows it to be easily extended and customized. NRDP uses standard ports and protocols (

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...

and

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...

) and can be implemented as a replacement for Nagios Service Check Acceptor (NSCA).

NSClient++

This program is mainly used to monitor

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

machines. Being installed on a remote system NSClient++ listens to port TCP 12489. The Nagios plugin that is used to collect information from this addon is called check_nt. As NRPE, NSClient++ allows to monitor the so-called 'private services' (memory usage, CPU load, disk usage, running processes, etc.) Nagios is a host and service monitor which is designed to inform you of network problems.

NCPA

The Nagios Cross Platform Agent is an

open source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

project maintained by Nagios Enterprises. NCPA installs on Windows, Linux, and Mac OS X. Created as a scale-able API that allows flexibility and simplicity in monitoring hosts. NCPA allows multiple checks such as memory usage, CPU usage, disk usage, processes, services, and network usage. Active checks are queried through the

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

of the "NCPA Listener" service while passive checks are sent via the "NCPA Passive" service.

Nagios XI

Nagios XI is a proprietary interface using Nagios Core as the back-end, written and maintained by the original author, Ethan Galstad, and Nagios Enterprises.

CentOS CentOS (, from Community Enterprise Operating System; also known as CentOS Linux) is a Linux distribution that provides a free and open-source community-supported computing platform, functionally compatible with its upstream source, Red Hat En ...

and

RHEL Red Hat Enterprise Linux (RHEL) is a commercial open-source Linux distribution developed by Red Hat for the commercial market. Red Hat Enterprise Linux is released in server versions for x86-64, Power ISA, ARM64, and IBM Z and a desktop version ...

are the currently supported

operating systems An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also inc ...

. It combines Nagios Core with other technologies. Its main database and the ndoutils module that is used alongside Nagios Core use

MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database o ...

. While the front-end of Nagios Core is mainly CGI with some PHP, most of the Nagios XI front-end and back-end are written in PHP including the subsystem, event handlers, and notifications, and

Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

is used to create

capacity planning Capacity planning is the process of determining the production capacity needed by an organization to meet changing demands for its products. In the context of capacity planning, design capacity is the maximum amount of work that an organization ...

reports and other reports.

RRDtool RRDtool (''round-robin database tool'') aims to handle time series data such as network bandwidth, temperatures or CPU load. The data is stored in a circular buffer based database, thus the system storage footprint remains constant over time. ...

and

Highcharts Highcharts is a software library for charting written in pure JavaScript, first released in 2009. The license is proprietary software, proprietary. It is free for personal/non-commercial uses and paid for commercial applications. It was cre ...

are included to create customizable graphs that can be displayed in

dashboards For business applications, see Dashboard (business). A dashboard (also called dash, instrument panel (IP), or fascia) is a control panel (engineering), control panel set within the central console of a vehicle or small aircraft. Usually located ...

2014 controversy over plugins website

On 16 January 2014, Nagios Enterprises redirected the nagios-plugins.org domain to a web server controlled by Nagios Enterprises without explicitly notifying the Nagios Plugins community team the consequences of their actions. Nagios Enterprises replaced the nagios-plugins team with a group of new, different members. The community team members who were replaced continued their work under the name Monitoring Plugins along with a new website with the new domain of monitoring-plugins.org.

References

External links

Official Nagios Website
* {{Authority control Internet Protocol based network software Free network management software Multi-agent systems Network analyzers Linux security software System administration System monitors