zeppelin spark context closed after one paragraph - scala

Question

I have a notebook in Zeppelin containing multiple paragraphs which were running fine earlier; suddenly, after a cluster restart, it has started behaving weirdly.
The first paragraph runs fine while anything that runs afterwards says Connection Refused.
On checking the logs in $ZEPPELIN_HOME/logs folder zeppelin-interpreter-spark-root-mn.log (where mn is machine name).
INFO [2018-02-21 21:42:43,301] ({dispatcher-event-loop-15} Logging.scala[logInfo]:54) - Removed broadcast_12_piece0 on mn5:45284 in memory (size: 88.2 KB, free: 2004.5 MB)
INFO [2018-02-21 21:42:43,401] ({Thread-3} Logging.scala[logInfo]:54) - Invoking stop() from shutdown hook
INFO [2018-02-21 21:42:43,412] ({Thread-3} AbstractConnector.java[doStop]:310) - Stopped Spark#7de3e842{HTTP/1.1,[http/1.1]}{0.0.0.0:4040}
INFO [2018-02-21 21:42:43,416] ({Thread-3} Logging.scala[logInfo]:54) - Stopped Spark web UI at http://10.28.37.82:4040
INFO [2018-02-21 21:42:43,440] ({Yarn application state monitor} Logging.scala[logInfo]:54) - Interrupting monitor thread
INFO [2018-02-21 21:42:43,442] ({Thread-3} Logging.scala[logInfo]:54) - Shutting down all executors
INFO [2018-02-21 21:42:43,443] ({dispatcher-event-loop-4} Logging.scala[logInfo]:54) - Asking each executor to shut down
INFO [2018-02-21 21:42:43,447] ({Thread-3} Logging.scala[logInfo]:54) - Stopping SchedulerExtensionServices
(serviceOption=None,
services=List(),
started=false)
INFO [2018-02-21 21:42:43,450] ({Thread-3} Logging.scala[logInfo]:54) - Stopped
INFO [2018-02-21 21:42:43,454] ({dispatcher-event-loop-9} Logging.scala[logInfo]:54) - MapOutputTrackerMasterEndpoint stopped!
INFO [2018-02-21 21:42:43,466] ({Thread-3} Logging.scala[logInfo]:54) - MemoryStore cleared
INFO [2018-02-21 21:42:43,466] ({Thread-3} Logging.scala[logInfo]:54) - BlockManager stopped
INFO [2018-02-21 21:42:43,467] ({Thread-3} Logging.scala[logInfo]:54) - BlockManagerMaster stopped
INFO [2018-02-21 21:42:43,471] ({dispatcher-event-loop-0} Logging.scala[logInfo]:54) - OutputCommitCoordinator stopped!
INFO [2018-02-21 21:42:43,472] ({Thread-3} Logging.scala[logInfo]:54) - Successfully stopped SparkContext
INFO [2018-02-21 21:42:43,473] ({Thread-3} Logging.scala[logInfo]:54) - Shutdown hook called
So the shut down hook is getting called. I have tried to check other posts on SO (like this and this) but it didn't help. Logs are not much helpful either.
Do I need to tweak code to add additional logging to fix this problem? Has someone has already faced and resolved the same?

Answer 1

It turned out to be the case of bad logging. I had checked yarn logs as well but couldn't find anything. It turns out that second paragraph had a RunTimeException which wasn't clear from any of the logs, but when i tried same command on spark-shell then i Realized what the problem was and fixed the same.
Run the scala command in spark-shell then see what exception it is throwing.