If the Events Service is not stopped gracefully before restarting the system or if the Events Service process is killed abruptly, the Events Service start will fail. The Events Service log will have the below entry:
ERROR] [main] [c.a.common.framework.AbstractApp] Severe error occurred while starting application [events-service-api-store]. Shutdown procedure will commence soon java.lang.RuntimeException: Unable to create file [/opt/AppDynamics/Controller/events_service/bin/../events-service-api-store.id] to store the process id because it already exists. Please stop any currently running process and delete the process id file
A graceful shutdown of the Events Service results in clearing the events-service-api-store.id. At the next startup, this file is created again by the Events Service. In case of abrupt shutdown of the Events Service, this file is not removed and during the next startup the Events Service will not be able to create this file. This cause the start-up failure for the Events Service.
Remove the events-service-api-store.id file located in <EventsServiceHome> directory and then start the Events Service process. To avoid this scenario, always perform a graceful shutdown of the Events Service.