Chef
Configuration management tool which uses a pure-Ruby, domain-specific language (DSL) for writing system configuration recipes. Supports Linux, UNIX, Windows, and AIX as first-class citizens for management.
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FastForward
Flexible operating-system event and metric forwarding agent. Receives input and forwards output using plugins.
linux windows osx open-source metrics monitoring ruby
Fig
A package management tool, similar to Ivy/APT, but language agnostic, faster and works well with both executables and libraries.
linux windows osx open-source packaging ruby
KairosDB
KairosDB is a fast distributed scalable time series database written on top of Cassandra. RESTful JSON-based query/results. Includes flot-based visualization.
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Puppet
Puppet is a tool designed to manage the configuration of Unix-like and Microsoft Windows systems declaratively.
linux windows osx open-source config-mgmt ruby
Vagrant Cachier
A Vagrant plugin that helps you reduce the amount of coffee you drink while waiting for boxes to be provisioned by sharing a common package cache among similiar VM instances.
linux windows osx open-source virt artifacts ruby
Veewee
veewee is a great tool for building Virtual Machine images (aka base boxes). It automates most of the steps and allows you to easily create readymade images for VirtualBox/Vagrant, VMWare Fusion, KVM and Parallels. No longer need to shy away from building custom VM images!
linux osx windows open-source virt packaging ruby