L4Re is an operating system framework for building systems with real-time, security, safety and virtualization requirements. It consists of the L4Re hypervisor/kernel and a user-level infrastructure that includes basic services such as program loading and memory management. L4Re also provides the environment for applications, including libraries and process-local functionality. L4Re has been released in the form of open source snapshots and also an increasing number of L4Re components has been published on GitHub. This talk will show how some of them can be composed together to create a functional microkernel-based system.