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
Eucalyptus
An open source software for building Amazon EC2-compatible private and hybrid cloud platforms
linux open-source virt cloud-paas c
Instrumental
Instrumental is a real-time, high-scale application and server monitoring tool with intelligent alerts, a powerful query language, and free development accounts.
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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