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
ConDep
ConDep is a open source infrastructure configuration and deployment DSL (Domain Specific Language) specifically targeted to (but not limited to) the Windows Server platform. If your familiar with tools like Chef and Puppet, ConDep does very much the same, but with native support for Windows.
windows open-source ci provisioning config-mgmt net
Rex
A agent-less server orchestration tool built on Perl
linux windows osx open-source orchestration perl
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