Zabbix
4.0 fan 5 stjerren (basearre op 1 resinsje)
Zabbix is an open-source software tool to monitor IT infrastructure such as networks, servers, virtual machines, and cloud services. Zabbix collects and displays basic metrics.
The software itself seems to be trade-free. The website though offers some consulting which one would need to pay for: https://www.zabbix.com/consulting – therefore 4/5 blocks.