Enable simple password for root user on CentOS

  1. vi /etc/pam.d/system-auth as root.

  2. Look for the following two lines:

    password    requisite     pam_cracklib.so try_first_pass retry=3
    password    sufficient    pam_unix.so md5 shadow nullok try_first_pass use_authtok
    
  3. Comment out the first of the two lines:

    #password    requisite     pam_cracklib.so try_first_pass retry=3
    
  4. Remove use_authtok on the second line. Otherwise you’ll get “passwd: Authentication information cannot be recovered” error.

    password    sufficient    pam_unix.so md5 shadow nullok try_first_pass
    
  5. That’s it. Try changing your password again.