1. A computer program product for providing stream processing with runtime adaptation, the computer program product comprising: a tangible storage device readable by a processing circuit and storing instructions for execution by the processing circuit to create an orchestrator configured to communicate with a runtime infrastructure and a stream processing application, the orchestrator configured to perform a method comprising: registering one or more events, wherein each of the events is associated with the stream processing application; monitoring, by a processor, for an occurrence of the one or more events associated with the stream processing application, wherein each of the one or more events is associated with one or more runtime metrics; receiving an event notification, wherein the event notification includes event identification and an event context; and based on receiving the event notification, executing an adaptation of the stream processing application, where the orchestrator includes APIs to influence a physical deployment of the stream processing application by changing a placement of operators in hosts and partitioning of operators in processing elements.