Kerrighed is a Single System Image operating system for clusters. It offers the view of a unique SMP machine on top of a cluster of standard PCs.

Kerrighed is implemented as an extension to the Linux operating system (a set of modules and a patch to the kernel). Current development version is based on Linux 2.6.30.

Main available features are:
* Cluster wide process management with customizable load balancing over the cluster (through process migration and remote forking)
* Cluster wide shared memory
* Application checkpointing
* Node addition/removal