具体信息如下：
[hadoop@mini1 hadoop-2.6.4]$ hadoop fs -mkdir /file
mkdir: Cannot create directory /file. Name node is in safe mode.从错误信息可以看到hadoop当前的namenode是处于安全模式。
解决：
[hadoop@mini1 hadoop-2.6.4]$ hadoop dfsadmin -safemode leave
DEPRECATED: Use of this script to execute hdfs command is deprecated. Instead use the hdfs command for it. Safe mode is OFF