What are some alternatives?
When comparing OpenNMS and LibreNMS, you can also consider the following products
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Pulseway - Pulseway changes the enterprise monitoring and management game with its mobile management solution.
Icinga - Icinga is a fork of Nagios and is backward compatible.
PRTG Network Monitor - An advanced network monitoring solution to monitor network up/downtime, traffic and usage.