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.

   ...
   CLOCKS:ARM Core=1000Hz, AXI=500Hz, APB=125Hz, Peripheral=500Hz
   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
   

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

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