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

Monit

An open source utility for managing and monitoring processes, programs, files, directories and filesystems

     

linux osx open-source monitoring process-mgmt c

Zabbix

An open source, enterprise-class monitoring framework

     

linux windows osx open-source monitoring c

Zipkin

A distributed request tracking system, useful for micro-service and distributed architectures written in Scala

     

linux windows osx open-source monitoring scala