Nagios

Stands for: Nagios Ain't Gonna Insist On Sainthood: Ethan Galstad's NetSaint of 1999, renamed in 2002

The open source monitoring system Ethan Galstad released as NetSaint on 14 March 1999 and renamed Nagios in 2002; a scheduler that runs plugins and reads their exit codes, with a St. Paul company behind it since 2007 and a family of forks around it.

Nagios is an open source network and infrastructure monitoring system that watches hosts, services and network devices, sends alerts when components fail and again when they recover. Ethan Galstad released NetSaint 0.0.1 on 14 March 1999 with host and service monitoring via plugins and notifications by e-mail and pager; in 2002, after the owners of a similarly named trademark raised a legal challenge, he renamed it Nagios, a recursive acronym for Nagios Ain't Gonna Insist On Sainthood, with 'agios' the Greek for saint. The design is a plugin model: Nagios Core performs no checks itself but executes external programs that test one service or resource and return 0 for OK, 1 for warning, 2 for critical or 3 for unknown, so anyone who can write a script can monitor anything. It is written in C, licensed under the GPLv2, and runs on Linux and other Unix systems. Galstad founded Nagios Enterprises in 2007 in St. Paul, Minnesota, for commercial support and the proprietary Nagios XI; Icinga forked the project in May 2009, and the 2014 redirection of the nagios-plugins.org domain produced the separate Monitoring Plugins project.

The model. Nagios Core does not perform monitoring checks directly. Its scheduler runs check plugins at configured intervals, processes the results and triggers notifications; each plugin tests a specific service or resource and returns a status code, 0 OK, 1 WARNING, 2 CRITICAL, 3 UNKNOWN, with a line of text. Hundreds of community-developed plugins exist for specific services and hardware, and the architecture is why the system spread through the 2000s: the monitoring server knew nothing about Oracle, printers or UPS batteries, and did not need to, because someone had written a forty-line script that did. Written in C, it runs on Linux and other Unix systems under the GPLv2.

The history. Galstad released NetSaint 0.0.1 on 14 March 1999; it was registered on SourceForge about two months before the project that became OpenNMS. In 2002 the owners of a similarly named trademark raised a legal challenge and, although an agreement was reached, Galstad changed the name to avoid future disputes, choosing Nagios, which links to the old name through the Greek 'agios'. Nagios 2.0 in February 2006 brought a redesigned web interface and the Event Broker module API, which let third-party software reach the internal data structures; 3.0 in March 2008 added adaptive monitoring and better performance for large installations; 4.0 in September 2013 added worker processes for parallel check execution and a redesigned CGI interface.

The company and the products. Galstad founded Nagios Enterprises in 2007 in St. Paul, Minnesota, to provide commercial support and the proprietary Nagios XI; the company's own history says Nagios began in 1999 when he developed the open source Nagios Core engine. The product line today is Nagios XI, the enterprise product, Nagios Core, the open source engine, Nagios Log Server, Nagios Network Analyzer for flow analysis and Nagios Fusion for a view across many servers.

The forks, which are part of the story. In May 2009 a group of community developers forked Nagios as Icinga, citing slow development, lack of community involvement in decisions and insufficient response to submitted patches; Icinga initially kept compatibility with Nagios plugins and configuration files, and Icinga 2 in 2014 was a ground-up rewrite with a new configuration language and distributed monitoring. On 16 January 2014 Nagios Enterprises redirected the nagios-plugins.org domain to a server it controlled without notifying the community plugin team; the displaced maintainers continued their work as Monitoring Plugins at monitoring-plugins.org. Shinken (2009), Naemon (2013) and Checkmk are the other derivatives of the plugin model. A project that made monitoring a community craft then lived through what a community does when it disagrees, and the result is that a Nagios plugin written in 2004 still runs on half a dozen systems today.

Beside the others. Zabbix kept one company and one code base; OpenNMS kept a foundation-like governance beside its company; Nagios kept the simplest possible contract between the scheduler and the check, and that simplicity is why it is still the first monitoring system many engineers install. The Nagios record on the industry timeline carries the company's dates.

Also known as: netsaint, nagios core, nagios xi, icinga, nagios plugins

Sources

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