Event-based Simulation for Transient Systems with Capture Replay to Predict Self-Adaptive Systems (Work in Progress Paper).

Cloud-native systems are dynamic in nature as they always have to react to changes in the environment, e.g., how users utilize the system. Self-adaptive cloud-native systems manage those changes by predicting how future environmental changes will impact the system's service level objectives and how the system can subsequently reconfigure to ensure that the service level objectives stay fulfilled. The farther the predictions look into the future, the higher the chance that good reconfigurations can be identified and applied. However, this requires efficient exploration of potential future system states, particularly exploring alternative futures resulting from alternative system reconfiguration. We present in this paper an extension to the Slingshot simulator for Palladio component models to efficiently explore the future state space induced by environmental changes and reconfigurations. The extension creates snapshots of simulation states and reloads them to explore alternatives. We show that Slingshot's event-based publish-subscribe architecture enables us to extend the simulator easily and without changes to the simulator itself.