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
FastForward
Flexible operating-system event and metric forwarding agent. Receives input and forwards output using plugins.
linux windows osx open-source metrics monitoring 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
Instrumental
Instrumental is a real-time, high-scale application and server monitoring tool with intelligent alerts, a powerful query language, and free development accounts.
linux windows oxs free metrics commercial metrics monitoring visualization php ruby python net java nodejs
Orc
A model driven orchestration tool for deployment of application clusters
linux windows osx open-source provisioning orchestration ruby
SignalFx
SignalFx is an advanced monitoring and alerting solution for modern infrastructure. With SignalFx, development and operations teams monitor, analyze, and alert in real-time on any time series data.
linux windows oxs commercial go python c metrics monitoring visualization
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