产生问题原因：
环境hadoop2，cdh5创建
使用hadoop fs -mdkir /use/xxx创建文件路径时，出现权限问题
前提我们已经把当前用户zhangsan和root放到/etc/suders中。
su root vi /etc/sudoers root ALL=(ALL) ALL zhangsan ALL=(ALL) NOPASSWD:ALL su zhangsan [zhangsan@cdh107 ~]$ hadoop fs -ls /user Found 7 items drwxrwxrwx - mapred hadoop 0 2018-11-12 14:07 /user/history drwxrwxr-t - hive hive 0 2018-11-12 14:09 /user/hive drwxrwxr-x - hue hue 0 2018-11-12 14:09 /user/hue drwxrwxr-x - impala impala 0 2018-11-12 14:09 /user/impala drwxrwxr-x - oozie oozie 0 2018-11-12 14:09 /user/oozie drwxr-x--x - spark spark 0 2018-11-12 15:14 /user/spark drwxrwxr-x - sqoop2 sqoop 0 2018-11-12 14:08 /user/sqoop2
创建目录/user/zhangsan抛出异常：
[zhangsan@cdh107 ~]$ hadoop fs -mkdir /user/wangyou mkdir: Permission denied: user=zhangsan, access=WRITE, inode="/user":hdfs:supergroup:drwxr-xr-x [zhangsan@cdh107 ~]$ sudo hadoop fs -mkdir /user/wangyou mkdir: Permission denied: user=root, access=WRITE, inode="/user":hdfs:supergroup:drwxr-xr-x
解决步骤：
1.查看/user目录的用户和用户组
[zhangsan@cdh107 ~]$ hadoop fs -ls / Found 3 items drwxr-xr-x - hbase hbase 0 2018-11-12 14:59 /hbase drwxrwxrwt - hdfs supergroup 0 2018-11-12 14:09 /tmp drwxr-xr-x - hdfs supergroup 0 2018-11-12 14:09 /user
备注：从上边可以看出我们想在/user路径下创建用户，但是/user路径的用户是hdfs，用户组是supergroup，当我们使用zhangsan或者root时提示创建失败，因此我们要修改创建/user/wangyou的用户。
2.使用hdfs这个用户登录来创建目录/user/wangyou
[zhangsan@cdh107 ~]$ sudo -uhdfs hadoop fs -mkdir /user/wangyou [zhangsan@cdh107 ~]$ hadoop fs -ls /user Found 8 items drwxr-xr-x - hdfs supergroup 0 2018-11-13 16:43 /user/wangyou drwxrwxrwx - mapred hadoop 0 2018-11-12 14:07 /user/history drwxrwxr-t - hive hive 0 2018-11-12 14:09 /user/hive drwxrwxr-x - hue hue 0 2018-11-12 14:09 /user/hue drwxrwxr-x - impala impala 0 2018-11-12 14:09 /user/impala drwxrwxr-x - oozie oozie 0 2018-11-12 14:09 /user/oozie drwxr-x--x - spark spark 0 2018-11-12 15:14 /user/spark drwxrwxr-x - sqoop2 sqoop 0 2018-11-12 14:08 /user/sqoop2
3.通过hdfs用户更改所在用户的权限
[zhangsan@cdh107 ~]$ sudo -uhdfs hadoop fs -chown zhangsan:zhangsan /user/wangyou [zhangsan@cdh107 ~]$ hadoop fs -ls /user Found 8 items drwxr-xr-x - zhangsan zhangsan 0 2018-11-13 16:43 /user/wangyou drwxrwxrwx - mapred hadoop 0 2018-11-12 14:07 /user/history drwxrwxr-t - hive hive 0 2018-11-12 14:09 /user/hive drwxrwxr-x - hue hue 0 2018-11-12 14:09 /user/hue drwxrwxr-x - impala impala 0 2018-11-12 14:09 /user/impala drwxrwxr-x - oozie oozie 0 2018-11-12 14:09 /user/oozie drwxr-x--x - spark spark 0 2018-11-12 15:14 /user/spark drwxrwxr-x - sqoop2 sqoop 0 2018-11-12 14:08 /user/sqoop2
如果spark2-shell出现这个错误，如何解决参考《问题解决：Permission denied: user=root, access=WRITE, inode="/user":hdfs:supergroup:drwxr-xr-x》