Upsilon is a distributed, flexible, and extensible system monitoring application. Being distributed means you run service checks on Upsilon nodes in your network where it makes sense, either on every server or on a management network, inside or outside the firewall. You can run checks on secure, hard to reach networks, and push those results to a central server. You can optionally execute "agentless" checks just by using SSH. Being flexible means that if you can script it, you can monitor it. Unlike most monitoring systems, the monitoring scripts are external to the main server, so you can use Upsilon to execute your monitoring scripts in an extremely robust way. Upsilon has been used to monitor many different things and is API-compatible with all nagios monitoring scripts. Being extensible means you can add monitoring checks to Upsilon at runtime without needing to restart the server. The upsilon-node and upsilon-web projects both have their own REST APIs.
Adagios is a Web-based Nagios configuration interface built to be simple and intuitive in design, exposing less of the clutter under the hood of Nagios. It has a REST interface for both status and configuration data as well a feature complete status interface that can be used as an alternative to the Nagios Web interface.
check_nwc_health is a plugin for the Shinken (or Nagios/Icinga) monitoring system. It is used to check hardware health, environment, interfaces, pools, uptime, etc. of a great range of the most popular network components like switches, routers, firewalls, proxies, load balancers, etc. Currently it can monitor: Cisco IOS, Cisco Nexus, F5 BIG-IP, CheckPoint Firewall1, Juniper NetScreen, HP Procurve, Nortel, Brocade 4100/4900, EMC DS 4700, EMC DS 24, Allied Telesyn, and Blue Coat SG600.
Monitoring::Spooler is a handy queue manager for queueing and delivery of monitoring notifications. It is able to handle several groups of on-call personnel and provides an extensible plugin mechanism to connect it to virtually any remote service which provides some kind of API. It is designed to work nicely with App::Standby.
RealOpInsight is an advanced business service monitoring dashboard toolkit for Nagios, Zabbix, Zenoss, Icinga, and other common monitoring systems including GroundWork, Centreon, Shinken, and op5 Monitor. It provides features for effective monitoring in demanding operations such as clouds, network operations centers, and large data centers.
SysopView shows information in a visually attractive way, like computers in movies do. The idea is that it can show information relevant to system administrators non-comprehensible for non-technical personnel, while still looking attractive even if you don't know what is shown. The current version can show nagios status data, webcam streams (mjpeg, jpeg, and video4Linux), and VNC, has a built-in terminal emulator in which regular text applications can be run, can sniff the network (including remotely) and dissect streams and show pictures which are sniffed, can show external bitmaps (from, for example, mrtg and rrdtool), and can scroll text (currently showing output of rssfeeds).
SpurTracer is a push-notification based monitoring solution for heterogenous loosely coupled IT infrastructures. It complements a service-endpoint monitoring solution like Nagios with a component-level interface auto-discovery. It automatically provides a certain level of functional tracing along with many non-functional measurements (e.g. call, error and timeout rates, interface latency, component execution, etc.). While being zero config itself, SpurTracer relies on you adding push notification support to the components you want to monitor. The best way to use SpurTracer is by adding punctual tracing to components in your infrastructure on-demand.