我正在WindowsUbuntu子系统上配置Hadoop2.7.3。我曾经 root 作为根帐户密码，但是当我尝试运行/bin/start-yarn.sh时，需要输入root@localhost

lizhi@localhost's password:

我试过根，但从未奏效。
我也试过了

ssh-genkey 
cat /home/user/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys

但是调用./start-yarn.sh时仍然需要密码，这个密码是什么，为什么和root帐户密码不同？
我尝试使用passwd将密码更改为root，但仍然被拒绝：

C:\Users\lizhi>bash
lizhi@LAPTOP-SURFACEP:/mnt/c/Users/lizhi$ sudo su
[sudo] password for lizhi:
root@LAPTOP-SURFACEP:/mnt/c/Users/lizhi# passwd
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
root@LAPTOP-SURFACEP:/mnt/c/Users/lizhi# ssh localhost
root@localhost's password:
Permission denied, please try again.
root@localhost's password:
Permission denied, please try again.
root@localhost's password:
Received disconnect from 127.0.0.1: 14:
root@LAPTOP-SURFACEP:/mnt/c/Users/lizhi#

欢迎咨询。