when enabling eventlog in standalone mode, if give the wrong configuration, the standalone cluster will down (cause master restart, lose connection with workers).
How to reproduce: just give an invalid value to "spark.eventLog.dir", for example: spark.eventLog.dir=hdfs://tmp/logdir1, hdfs://tmp/logdir2. This will throw illegalArgumentException, which will cause the Master restart. And the whole cluster is not available.
This is not acceptable that cluster is crashed by one application's wrong setting.