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
ConDep
ConDep is a open source infrastructure configuration and deployment DSL (Domain Specific Language) specifically targeted to (but not limited to) the Windows Server platform. If your familiar with tools like Chef and Puppet, ConDep does very much the same, but with native support for Windows.
windows open-source ci provisioning config-mgmt net
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
Rex
A agent-less server orchestration tool built on Perl
linux windows osx open-source orchestration perl
Soloist
Soloist lets you quickly and easily converge Chef recipes using chef-solo.
linux windows osx open-source provisioning ruby
Vagrant
Vagrant is a cross platform tool to create, boot, configure and destroy development environments. It provides a simple configuration-based approach to take a base image, boot it up, provision it (using any other provisioners), SSH, port forward, and much more. It automates the process of booting up and configuring virtual machines. It supports various providers like VirtualBox, VMWare, AWS, LXC, etc.
linux windows osx open-source virt provisioning ruby