Baserock is a FOSS project originally founded by Codethink in 2011, licensed GPLv2. It is a great open source way to produce custom software systems which are expected to require ongoing maintenance and updates.
Baserock is designed to address embedded systems and dedicated enterprise appliance projects that need:
• repeated, effective, dependable delivery
• of whole software systems including OS, apps, configuration, build infrastructure
• and binary content (FOSS and/or proprietary IP) to deploy on such systems
• based on multiple architectures and/or chipsets
• where updates are feasible and expected
• and where other approaches (distros, platforms, build systems) are inappropriate