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

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

Supervisord Monitor

Supervisord Monitor is multi server monitoring tool for supervisor - watch, start and stop all your supervisord instances and servvices from one place.

     

linux windows osx open-source monitoring provisioning php process-mgmt

Zabbix

An open source, enterprise-class monitoring framework

     

linux windows osx open-source monitoring c