Major Description
When the Zeppelin server is stopped (e.g., with a SIGTERM), it should also stop all interpreter processes that it has started. Instead, I sometimes see them hang around as orphaned children after the Zeppelin server has stopped. This seems to be the case with the spark interpreter (at least with yarn-client mode; haven't tested with standalone or local modes) and with the shell interpreter. It does not seem to occur with the hive or angular interpreters; those ones stop when the server is stopped.