is it a because of task not submitting to sql?
2016-07-27T23:20:27,141 INFO [task-runner-0-priority-0] io.druid.indexing.common.actions.RemoteTaskActionClient [] - Submitting action for task[index_test_cluster_2016-07-27T23:20:16.653Z] to overlord[
http://xxx.xxx.xxx.xxx:48080/druid/indexer/v1/action]: SegmentInsertAction{segments=[DataSegment{size=3892370, shardSpec=NoneShardSpec, metrics=[numz], dimensions=[ts, lres, mDist, cc, csz, dmk, crev, snrt, cown, ntDist, sagem, sagef, hsp, ucid], version='2016-07-28T00:01:00.000Z', loadSpec={type=s3_zip, bucket=bucket, key=cluster-segement/test_cluster/2016-07-28T00:01:00.000Z_2016-07-28T00:02:00.000Z/2016-07-28T00:01:00.000Z/0/index.zip}, interval=2016-07-28T00:01:00.000Z/2016-07-28T00:02:00.000Z, dataSource='test_cluster', binaryVersion='9'}]}
2016-07-27T23:20:27,190 WARN [task-runner-0-priority-0] io.druid.indexing.common.actions.RemoteTaskActionClient [] - Exception submitting action for task[index_test_cluster_2016-07-27T23:20:16.653Z]
java.io.IOException: Scary HTTP status returned: 500 Server Error. Check your overlord[xxx.xxx.xxx.xxx:48080] logs for exceptions.
at io.druid.indexing.common.actions.RemoteTaskActionClient.submit(RemoteTaskActionClient.java:123) [druid-indexing-service-0.9.1-SNAPSHOT.jar:0.9.1-SNAPSHOT]
at io.druid.indexing.common.TaskToolbox.publishSegments(TaskToolbox.java:224) [druid-indexing-service-0.9.1-SNAPSHOT.jar:0.9.1-SNAPSHOT]
at io.druid.indexing.common.task.IndexTask.run(IndexTask.java:280) [druid-indexing-service-0.9.1-SNAPSHOT.jar:0.9.1-SNAPSHOT]
at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:436) [druid-indexing-service-0.9.1-SNAPSHOT.jar:0.9.1-SNAPSHOT]
at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:408) [druid-indexing-service-0.9.1-SNAPSHOT.jar:0.9.1-SNAPSHOT]
at java.util.concurrent.FutureTask.run(FutureTask.java:262) [?:1.7.0_101]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [?:1.7.0_101]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [?:1.7.0_101]
at java.lang.Thread.run(Thread.java:745) [?:1.7.0_101]
2016-07-27T23:20:27,195 INFO [task-runner-0-priority-0] io.druid.indexing.common.actions.RemoteTaskActionClient [] - Will try again in [PT4.709S].