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
Nomad
Nomad is a lightweight workload orchestrator. It offers client instance scaling as well as workload scaling.
linux windows osx open-source virt orchestration go
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
Rex
A agent-less server orchestration tool built on Perl
linux windows osx open-source orchestration perl
Serf
Serf is a service discovery and orchestration tool which is highly decentralized, highly available, fault tolerant, cross platform and extremely lightweight.
linux windows osx open-source orchestration go