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
Fabric
Fabric is a python framework to configure deployment or system administration tasks, and then run those tasks on local or remote systems. It uses SSH heavily for interacting with remote systems, and uses Roles to group tasks
linux osx open-source orchestration python
Phabricator
Phabricator is an open source collection of development and code management, including code reviews and audits, browsing repositories, tracking bugs, etc
linux osx open-source scm php
SaltStack
Salt is a powerful and different approach to infrastructure management, by focusing on high speed communications between large number of systems, and can perform orchestration, remote code execution and much more.
linux windows osx open-source commercial config-mgmt provisioning orchestration python