试了网上很多种方法都不行，求大神帮忙，感激不尽！！
我在用docker搭建hadoop集群的时候，hadoop成功启动了，但是执行grep的时候报错了：
./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar grep /usr/hadoop/input output ‘dfs[a-z.]+’
INFO client.RMProxy: Connecting to ResourceManager at master/172.17.0.2:8032
INFO ipc.Client: Retrying connect to server: master/172.17.0.2:8032. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
INFO ipc.Client: Retrying connect to server: master/172.17.0.2:8032. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
INFO ipc.Client: Retrying connect to server: master/172.17.0.2:8032. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
INFO ipc.Client: Retrying connect to server: master/172.17.0.2:8032. Already tried 3 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
不知道哪里配置错了，已经看了防火墙，没有安装防火墙。yarn-site.xml是这么配置的：
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
