What is the password for root@localhost's password?

Question

I'm configuring the hadoop 2.7.3 on windows ubuntu subsystem. I used root as the root account password, but when I try to run /bin/start-yarn.sh, I was required to input the password for root@localhost

lizhi@localhost's password:

I have tried root for this, but never worked.

I have also tried

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

But it still required a password when calling ./start-yarn.sh, what is the password for this, why is it different with root account password?

I've tried to change password to root using passwd, and I still get denied:

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#

Welcome for any advise.

Answer 1

It is blank (as in "") unless you set it:

ssh root@localhost uses the same password for root. It looks like you have not set root password. To do that log in as root using sudo -s then use passwd command to set root password.

After that you must be able to ssh as root

• https://askubuntu.com/questions/9017/how-to-know-my-root-password