openITCOCKPIT is open-source software for configuring Nagios or Naemon.
The most significant changes in this version:
- Data collection via a custom agent
- The frontend and backend interact entirely through the API
- Notifications through various chat systems (Slack, RocketChat, Mattermost, …)
- Automatic conversion of measurement units in graphs to simpler units
- Numerous improvements to the web interface
- and much more
Source: linux.org.ru

