Boxstarter
Repeatable, reboot resilient windows environment installations made easy using Chocolatey packages. When its time to repave either bare metal or virtualized instances, locally or on a remote machine, Boxstarter can automate both trivial and highly complex installations. Compatible with all Windows versions from Windows 7/2008 R2 forward.
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collectd
A daemon that collects system performance statistics periodically, and provides tons of plugins to store and analyze these values
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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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Nagios Core
Nagios Core network monitoring software is a powerful, enterprise-class host, server, application, monitoring and alerting tool
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Zabbix
An open source, enterprise-class monitoring framework
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