My tasks status are failed

I used kafka indexing-service to ingest my kafka data to druid. Overlord ui shows that there are tasks and a lot of tasks are failed, However, there had been many data in segments.Now I want to ask what caused the task failed.there are no error messages in logs,one of log files as attachement.

localhostdruid.log (182 KB)

请问你是在这段时间都没有数据摄入吗? 看看我的那个帖子,是不是和我一样的情况?
https://groups.google.com/forum/#!topic/druid-user/cIGviod2iFw

在 2018年4月16日星期一 UTC+8下午3:52:26,zhangxin…@gmail.com写道:

你好,可能不是和你一样的情况哦,可否进一步沟通?

微信OceanX000

在 2018年4月18日星期三 UTC+8上午7:51:33,张鑫写道:

你好,你这个问题最后定位下来是什么原因啊?我也遇到了相同的问题,想请教一下

在 2018年4月16日星期一 UTC+8下午3:52:26,Frank Zhang写道:

Hello,

Do you have the overlord or middlemanager logs ? I did not find any logs attached here.

Do you have task logs for failed tasks?

Thanks,

Surekha