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.
linux windows open-source provisioning config-mgmt 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
Fog
The Ruby Cloud API library. Provides a Ruby API for interacting and managing many cloud providers, such as spinning up new instances, terminating old ones, attaching storage, etc. Currently supports more than 20 providers, including EC2, Rackspace, Brightbox, etc.
linux windows osx open-source cloud-paas ruby
Orc
A model driven orchestration tool for deployment of application clusters
linux windows osx open-source provisioning orchestration ruby
Pallet
A tool to provision and maintain servers across various cloud platforms as well as virtual machine platforms, without any dependencies. Provides cloud and operating system independence.
linux windows osx open-source cloud-paas clojure
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