Overlays are reconfigurable architectures synthesized on commercial of the shelf (COTS) FPGAs. Overlays bring some advantages such as portability, resources abstraction, fast configuration, and can exhibit features independent from the host FPGA. We designed a fine-grained overlay implementing novel features easing the management of such architectures in a cluster of heterogeneous COTS FPGAs. This demonstration shows the use of this overlay in an FPGA cluster, performing a hardware application live migration between two nodes of a cluster. It also illustrates fault tolerance of the cluster.