为啥我执行mapreduce的时候每次map成功reduce都是失败?txt文件和程序都没有问题,hdfs,yarn也是正常启动的状态。在每次执行之前也都删除了输出路径的文件夹。错误的提示是:Error: org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /output/wc/_temporary/1/_temporary/attempt_1505957164428_0002_r_000000_2/part-r-00000 could only be replicated to 0 nodes instead of minReplication (=1). There are 1 datanode(s) running and no node(s) are excluded in this operation.