collectd
A daemon that collects system performance statistics periodically, and provides tons of plugins to store and analyze these values
linux windows osx open-source monitoring c
Instrumental
Instrumental is a real-time, high-scale application and server monitoring tool with intelligent alerts, a powerful query language, and free development accounts.
linux windows oxs free metrics commercial metrics monitoring visualization php ruby python net java nodejs
jclouds
A Java Library for controlling cloud resources, with various plugins for many popular cloud providers.
linux windows osx open-source cloud-paas java
jmxtrans
Plugs Java VM statistics via JMX to various backend monitoring tools
linux windows osx open-source monitoring java
Logstash
A modern tool for managing events and logs, with an ElasticSearch backend which allows a high degree of searching and filtering. It includes a shipper in remote systems, indexer in the aggregator machine, and a Web UI.
linux windows osx open-source monitoring java
Metrics
Captures JVM and application-level metrics for Java
linux windows osx open-source monitoring java
Monit
An open source utility for managing and monitoring processes, programs, files, directories and filesystems
linux osx open-source monitoring process-mgmt c
Nagios Core
Nagios Core network monitoring software is a powerful, enterprise-class host, server, application, monitoring and alerting tool
linux solaris bsd open-source monitoring c
Sentry
Automate error tracking to find and fix issues before your users even experience a crash. Sentry is open-source, real-time, and loved by 100,000 developers around the world.
osx windows linux open-source errors nodejs ruby python php java monitoring
Zabbix
An open source, enterprise-class monitoring framework
linux windows osx open-source monitoring c