A method to execute a mode-transition in a multi-mode computer system from a current to a future mode during run-time of the computer system, wherein the computer system comprises hosts with processing cores. A mode-transition is determined by a transition definition, wherein all transition definitions form a set of transition definitions, and wherein a transition definition between two defined modes comprises a reference to the initial mode, a reference to the future mode, and a list of specific actions to be executed during the mode-transition. A first function runs on a host of the hosts. A second function runs on a processing core of the hosts. Third functions are provided, wherein a third function is running on a processing core in each of the hosts of the computer system. Fourth functions are provided, wherein on each processing core of the computer system a fourth function is running.