hdfs刷新节点失败，未显示Refresh nodes successful

使用命令：hdfs dfsadmin -refreshNodes

没有显示Refresh nodes successful，而是：refreshNodes: /opt/module/hadoop-2.7.2/etc/hadoop/dfs.hosts.exclude

原因：hdfs-site.xml中dfs.hosts.exclude配置路径有换行错误

# 错误！
<property>
<name>dfs.hosts.exclude</name>
<value>/opt/module/hadoop-2.7.2/etc/hadoop/dfs.hosts.exclude
</value>
</property>

# 正确
<property>
<name>dfs.hosts.exclude</name>
<value>/opt/module/hadoop-2.7.2/etc/hadoop/dfs.hosts.exclude</value>
</property>