Zenoss Core Alternatives

Track, record, alert and visualize performance and availability of IT resources

Complete monitoring and alerting for servers, switches, applications, and services

PnP networked resource monitoring tool that can help to answer the what just happened to kill our performance

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.

Help desk software features that work for IT

Cacti is a complete network graphing solution. It provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features.

Monit is a free open source utility for managing and monitoring, processes, files, directories and filesystems on a UNIX system. Monit conducts automatic maintenance and repair and can execute meaningful causal actions in error situations.

Icinga is a fork of Nagios and is backward compatible.

An advanced network monitoring solution to monitor network up/downtime, traffic and usage.

Observium

Pandora FMS: Opensource monitoring software

A fully featured network monitoring system that provides a wealth of features and device support.

Self-hosted, easily-deployable monitoring and alerts service - like a lightweight PagerDuty