Open Source C++ Server Monitoring Tools

Pandora FMS is an enterprise-ready monitoring solution that provides unparalleled flexibility for IT to address both immediate and unforeseen operational issues, including infrastructure and IT processes. It uniquely enables business and IT to adapt to changing needs through a flexible and rapid approach to IT and business deployment. Pandora FMS consolidates all the needs of modern monitoring (ITOM, APM, BAM) and provides status and performance metrics from different operating systems, cloud, virtual infrastructure (VMware, Hyper-V, XEN), Docker containers, applications, storage and hardware devices such as firewalls, proxies, databases, web servers or routers. It's highly scalable (up to 2000 nodes with one single server), 100% web and with multi-tenant capabilities. It has a very flexible ACL system and several different graphical reports and user-defined control screens.

Rcon Controller: a SA:MP server administration tool. aims to provide real-time graphic/console monitoring / Instant managing. developed by CoolGuy.

Internet Dialier and Monitor Server

Crow's nest is a web based Unix(-like) server monitoring tool using interpreted language scripts as it's tests.

LiMon (Linux Monitor) is a free/open/libre multiplataform real time Linux monitor written in C/C++, and other languages. Monitor of server's relevant aspects, such as services, temperature, CPU, memory and disk usage, etc.

ghlrcon is gtk based half life server monitoring software (simmilar to HLSW)