collectd

A daemon that collects system performance statistics periodically, and provides tons of plugins to store and analyze these values

     

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Honeybadger

Honeybadger is a hosted monitoring service that tracks errors happening in your applications, aggregates them, and notifies you about them based on rules you define. Honeybadger gives you the insight you need to diagnose and fix application errors, faster.

     

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Instrumental

Instrumental is a real-time, high-scale application and server monitoring tool with intelligent alerts, a powerful query language, and free development accounts.

     

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Monit

An open source utility for managing and monitoring processes, programs, files, directories and filesystems

     

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Nagios Core

Nagios Core network monitoring software is a powerful, enterprise-class host, server, application, monitoring and alerting tool

     

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Netdata

netdata is a system for distributed real-time performance and health monitoring. It provides unparalleled insights, in real-time, of everything happening on the system it runs (including applications such as web and database servers), using modern interactive web dashboards.

     

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Rex

A agent-less server orchestration tool built on Perl

     

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Sentry

Automate error tracking to find and fix issues before your users even experience a crash. Sentry is open-source, real-time, and loved by 100,000 developers around the world.

     

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Supervisord Monitor

Supervisord Monitor is multi server monitoring tool for supervisor - watch, start and stop all your supervisord instances and servvices from one place.

     

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Zabbix

An open source, enterprise-class monitoring framework

     

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