What are some alternatives?
Zabbix - Track, record, alert and visualize performance and availability of IT resources
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.
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
Grafana - Data visualization & Monitoring with support for Graphite, InfluxDB, Prometheus, Elasticsearch and many more databases
Splunk - Splunk's operational intelligence platform helps unearth intelligent insights from machine data.
Sensu - Monitor servers, services, application health, and business KPIs. Get notified about failures before your users do. Collect and analyze custom metrics. Give your business the competitive advantage it deserves.