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
FAI
Fully Automatic Installation (FAI) is a tool for mass unattended deployment of Linux. You can take one or more virgin PCs, turn on the power, and after a few minutes, the systems are installed and completely configured.
linux open-source config-mgmt provisioning perl
Rex
A agent-less server orchestration tool built on Perl
linux windows osx open-source orchestration perl
Riemann
Riemann aggregates events from servers and applications, notifies exceptions, tracks latency, collects system statistics and more, all with a powerful stream processing language
linux open-source monitoring clojure