systemd - systemd is a replacement for the init daemon for Linux (either System V or BSD-style).
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
runit - runit is a cross-platform Unix init scheme with service supervision, a replacement for sysvinit...
AppDynamics - Get real-time insight from your apps using Application Performance Management—how they’re being used, how they’re performing, where they need help.
sysvinit - Savannah is a central point for development, distribution and maintenance of free software, both GNU and non-GNU.
Zabbix - Track, record, alert and visualize performance and availability of IT resources