錯誤具體詳情如下：
INFO mapreduce.Job: Job job_1510233562271_0004 failed with state FAILED due to: Application application_1510233562271_0004 failed 2 times due to Error launching appattempt_1510233562271_0004_000002. Got exception: java.net.ConnectException: Call From mini2/192.168.242.102
to localhost:52016 failed on connection exception: java.net.ConnectException: 拒絕連接; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused
解決方法：
修改hostname(主機名), vi /etc/sysconfig/network（如果沒修改默認爲localhost.localdomain），將其修改爲和你的/etc/hosts一致即可