我想在ubuntu 20.04上安装Hadoop2.10.1。当我想根据tutorial:hadoop：设置单节点群集。上面说：

yarnhdoop@tcguoxing-QJC4:~/hadoop-2.10.1$ bin/hdfs dfs -mkdir /user
mkdir: Cannot create directory /user. Name node is in safe mode.

然后我想让name node离开安全模式，它说：

yarnhdoop@tcguoxing-QJC4:~/hadoop-2.10.1$ bin/hdfs dfsadmin -safemode leave
safemode: Access denied for user yarnhdoop. Superuser privilege is required

所以我认为用户'yarnhdoop'不够高，然后我在用户'root'下执行这个命令。上面写着：

root@tcguoxing-QJC4:/home/yarnhdoop/hadoop-2.10.1# bin/hdfs dfsadmin -safemode leave
safemode: Access denied for user root. Superuser privilege is required

下面的步骤困扰了好几天。

我应该换成旧的hadoop版本吗？