Munin

Free plan APILinuxSelf-hosted

What Munin is

Munin is free, open-source software for monitoring networked resources and examining trends and performance problems. It collects metrics through a master-and-node design: a master regularly connects to monitored nodes, with servers polled once every five minutes. Munin presents the collected information as graphs in a web interface and stores it in RRD files. It can monitor computers, networks, storage area networks, applications, and weather measurements.

The project offers more than 500 plugins and lets users create custom plugins in any language. Administrators can set alerts for plugin data that passes defined limits, using command-line tools or systems such as Nagios and Icinga. SNMP plugins can collect information from remote machines. TLS can encrypt communication between master and nodes, with certificate verification against a shared certificate authority as an option.

Munin is self-hosted. For package-based installation, the project recommends installing munin-node on each monitored node and munin on the master. Described deployments range from a home Raspberry Pi to clusters with more than 100 nodes. The project began in 2002 and directs users to its FAQ, guide, IRC channel, mailing list archive, and GitHub issues for support.

Who it suits

Munin suits administrators who want self-hosted monitoring across computers, networks, applications, or other supported resources. Its plugin system, alert options, and master-and-node architecture also suit setups that need configurable metric collection across multiple nodes.

What it does well

Free, open-source monitoring software.
Graphs collected information through a web interface.
More than 500 plugins, with custom plugins supported in any language.
TLS can encrypt master-to-node communication.
Deployments described from a Raspberry Pi to clusters over 100 nodes.

What to know first

Requires a self-hosted deployment.
Packaged installs require munin-node on each node and munin on the master.
The homepage lists version 2.0.69 as the latest stable release.

Plans

Plan	Billed and limits	Price
Munin	open-source monitoring software · packages, tarballs or source	Free

As munin-monitoring.org lists them, read 11 Oct 2026. The maker's own page has the final word.

Getting started

Visit https://munin-monitoring.org/.
Choose the package-based installation route recommended by the project.
Install munin-node on each monitored node.
Install munin on the master.
Configure monitoring and any desired plugins or alerting.

Verdict

Choose Munin if you want free, self-hosted resource monitoring with graphing, a broad plugin ecosystem, and configurable alerts. Look elsewhere if you need a service that does not require a master-and-node installation you manage.

Questions

Is Munin free?

Yes. The listed Munin plan costs nothing, and the software is open source.

Where does Munin run?

Munin is self-hosted.

How does Munin collect metrics?

A master regularly connects to nodes, and servers are polled once every five minutes.

What can Munin monitor?

It can monitor computers, networks, SANs, applications, and weather measurements.

Can Munin send alerts?

Yes. Alerts can be triggered when plugin data breaches defined limits, using command-line tools or systems such as Nagios and Icinga.

Facts from Munin's own pages

Alerts: Munin can alert administrators when plugin data breaches defined limits, using command line tools or systems such as Nagios or Icinga. · guide.munin-monitoring.org, 11 Oct 2026
Architecture: Munin uses a master and node architecture in which the master regularly connects to nodes to collect metrics. · guide.munin-monitoring.org, 11 Oct 2026
Commercial support: The commercial offerings page says private support and training are no longer provided by the named lead developer for the foreseeable future. · munin-monitoring.org, 11 Oct 2026
Founded: 2002 · munin-monitoring.org, 28 Sept 2026
Graphs: Munin presents monitored information as graphs through a web interface and stores data in RRD files. · munin-monitoring.org, 11 Oct 2026
Install requirements: A packaged installation uses the munin-node package on each monitored node and the munin package on the master; the maker recommends packages over source installs. · munin-monitoring.org, 11 Oct 2026
Integrations: The maker documents alert integrations with Nagios and Icinga and supports SNMP plugins for collecting data from remote machines. · guide.munin-monitoring.org, 11 Oct 2026
Monitoring scope: Munin can monitor computers, networks, SANs, applications and weather measurements. · munin-monitoring.org, 11 Oct 2026
Plugins: The site says Munin has more than 500 available plugins and lets users write custom plugins in any language. · munin-monitoring.org, 11 Oct 2026
Polling: The maker says Munin polls servers once every five minutes. · munin-monitoring.org, 11 Oct 2026
Purpose: Munin is a networked resource monitoring tool for analyzing resource trends and performance problems. · munin-monitoring.org, 11 Oct 2026
Release information: The homepage lists version 2.0.69 as the latest stable release, posted November 22, 2021. · munin-monitoring.org, 11 Oct 2026
Scale: The maker describes deployments from a home Raspberry Pi to clusters with more than 100 nodes. · munin-monitoring.org, 11 Oct 2026
Security: Munin supports TLS for encrypted communication between master and nodes, with an option to verify certificates against a shared certificate authority. · guide.munin-monitoring.org, 11 Oct 2026
Support: The project points users to its FAQ, guide, OFTC IRC channel, mailing list archive and GitHub issues. · munin-monitoring.org, 11 Oct 2026