Why does switching root user fail?

Problem background:

It is necessary to apply for server root permission to maintain the storm project deployed on the server;
email application, approval, and reply; inform root user password
Server
: rent Alibaba Cloud server;
Execute su root, enter the notified password, and press Enter; incorret password prompts that the password is incorrect;
logout and re-login still fail

Problem analysis:
understanding

is wrong, su root switches from the current ordinary user to the root superuser, and the entered password is the current user's Password


Problem solving:

sudo su -i Enter the notified password, and the user switch is successful;

the password to be entered at this time is the root password

http://blog.csdn.net/yasi_xi/article/details/8493444