mapreduce job一直卡住

16/07/15 17:34:41 INFO input.FileInputFormat: Total input paths to process : 1
16/07/15 17:34:42 INFO mapreduce.JobSubmitter: number of splits:1
16/07/15 17:34:42 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1468574113266_0003
16/07/15 17:34:42 INFO impl.YarnClientImpl: Submitted application application_1468574113266_0003
16/07/15 17:34:42 INFO mapreduce.Job: The url to track the job: http://hdfs01.beta1:8088/proxy/application_1468574113266_0003/
16/07/15 17:34:42 INFO mapreduce.Job: Running job: job_1468574113266_0003

job一直卡主，nn，rm，nm，dn的日志都没有异常，只在nm的日志里仅有一条消息：

INFO org.apache.hadoop.yarn.server.nodemanager.NodeStatusUpdaterImpl: Notifying ContainerManager to unblock new container-requests

于是执行了yarn nodemanager命令，问题解决，原因待查