Prometheus: Collects metrics, provides alerting and graphs web UI
Prometheus provides a solution for collecting metrics from systems and applications and aggregating them into a central location.
Prometheus provides a solution for collecting metrics from systems and applications and aggregating them into a central location.
Telegraf is an agent for collecting system and application metrics from your servers, processing and aggregating the data. It can send the data to other services.
Statsd is a system for collecting system and application metrics from your servers, and make the information available over the network.
Collectd is a system for collecting system and application metrics from your servers, and make the information available over the network.
Riemann is a new modern open source monitoring tool under development (currently at version 0.2).
Etsy has a great presentation how to improve and extend Nagios functionality by adding configuration automation and reminders to the team: