Checkmk is a comprehensive Solution for IT Monitoring of applications, servers, and networks.
Jackett works as a proxy server: it translates queries from apps (Sonarr, Radarr, SickRage, CouchPotato, Mylar, DuckieTV, etc) into tracker-site-specific http queries, parses the html response, then sends results back to the requesting software.
Radarr is an independent fork of Sonarr reworked for automatically downloading movies via Usenet and BitTorrent.
The project was inspired by other Usenet/BitTorrent movie downloaders such as CouchPotato.
