Single User Mode - Password Recovery

Use single user mode to assist in troubleshooting system boot issues or for password recovery.

To enter single user mode:

1. Boot the switch, then as soon as you see the GRUB menu, use the arrow keys to select Advanced options for Cumulus Linux GNU/Linux.

   Before the GRUB menu appears, the switch goes through the boot cycle. Do not interrupt this autoboot process when you see the following lines; wait until you see the GRUB menu.

   ...
   USB0:  Bringing USB2 host out of reset...
   Net:   eth-0
   SF:    MX25L6405D with page size 4 KiB, total 8 MiB
   Hit any key to stop autoboot:  2
   

                GNU GRUB  version 2.02+dfsg1-20
   
   +----------------------------------------------------------------------------+
   |*Cumulus Linux GNU/Linux                                                    |
   | Advanced options for Cumulus Linux GNU/Linux                               |
   | ONIE                                                                       |
   |                                                                            |
   +----------------------------------------------------------------------------+
   

2. Select Cumulus Linux GNU/Linux, with Linux 4.19.0-cl-1-amd64 (recovery mode).

                GNU GRUB  version 2.02+dfsg1-20
   
   +----------------------------------------------------------------------------+
   | Cumulus Linux GNU/Linux, with Linux 4.19.0-cl-1-amd64                       |
   |*Cumulus Linux GNU/Linux, with Linux 4.19.0-cl-1-amd64 (recovery mode)       |
   |                                                                            |
   +----------------------------------------------------------------------------+  
   

3. After the system reboots, set a new root password. The root user provides complete control over the switch.

   root@switch:~# passwd
   Enter new UNIX password:
   Retype new UNIX password:
   passwd: password updated successfully
   

   You can take this opportunity to reset the password for the cumulus account.

      root@switch:~# passwd cumulus
      Enter new UNIX password:
      Retype new UNIX password:
      passwd: password updated successfully
   

   In Cumulus Linux 5.9 and later, user passwords must include at least one lowercase character, one uppercase character, one digit, one special character, and cannot be usernames. In addition, passwords must be a minimum of eight characters long, expire in 365 days, and provide a warning 15 days before expiration. For more information about the password security policy, refer to Password Security.

4. Sync the /etc directory, then reboot the system:

   root@switch:~# sync
   root@switch:~# reboot -f
   Restarting the system.