我有一个elasticmapreduce工作，它使用elasticsearch hadoop通过滚烫的点击将数据从amazons3传输到amazonalasticsearch服务。在很长一段时间内，这项工作都很成功。但是，它最近开始失败，出现以下堆栈跟踪：

2016-03-02 07:28:34,003 FATAL [IPC Server handler 0 on 41019] org.apache.hadoop.mapred.TaskAttemptListenerImpl: Task: attempt_1456902751849_0012_m_000000_0 - exited : cascading.tuple.TupleException: unable to sink into output identifier: myindex/mytable
        at cascading.tuple.TupleEntrySchemeCollector.collect(TupleEntrySchemeCollector.java:160)
        at cascading.tuple.TupleEntryCollector.safeCollect(TupleEntryCollector.java:145)
        at cascading.tuple.TupleEntryCollector.add(TupleEntryCollector.java:95)
        at cascading.tuple.TupleEntrySchemeCollector.add(TupleEntrySchemeCollector.java:134)
        at cascading.flow.stream.SinkStage.receive(SinkStage.java:90)
        at cascading.flow.stream.SinkStage.receive(SinkStage.java
:37)
        at cascading.flow.stream.FunctionEachStage$1.collect(FunctionEachStage.java:80)
        at cascading.tuple.TupleEntryCollector.safeCollect(TupleEntryCollector.java:145)
        at cascading.tuple.TupleEntryCollector.add(TupleEntryCollector.java:133)
        at com.twitter.scalding.MapFunction.operate(Operations.scala:59)
        at cascading.flow.stream.FunctionEachStage.receive(FunctionEachStage.java:99)
        at cascading.flow.stream.FunctionEachStage.receive(FunctionEachStage.java:39)
        at cascading.flow.stream.SourceStage.map(SourceStage.java:102)
        at cascading.flow.stream.SourceStage.run(SourceStage.java:58)
        at cascading.flow.hadoop.FlowMapper.run(FlowMapper.java:130)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:432)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:175)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1548)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:170)
Caused by: org.elasticsearch.hadoop.rest.EsHadoopInvalidRequest: null

我们已启用“es.nodes.wan.only”设置。
是什么导致了这次失败？