Use single user mode to assist in troubleshooting system boot issues or for password recovery. To enter single user mode, follow the steps below.

  1. Boot the switch, as soon as you see the GRUB menu. 

                           GNU GRUB  version 2.02~beta2-22+deb8u1
    
     +----------------------------------------------------------------------------+
     |*Cumulus Linux GNU/Linux                                                    | 
     | Advanced options for Cumulus Linux GNU/Linux                               |
     | ONIE                                                                       |
     |                                                                            |
     +----------------------------------------------------------------------------+     
  2. Use the ^ and v arrow keys to select Advanced options for Cumulus Linux GNU/Linux. A menu similar to the following should appear:

                           GNU GRUB  version 2.02~beta2-22+deb8u1
    
     +----------------------------------------------------------------------------+
     | Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-1-amd64                       | 
     | Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-1-amd64 (sysvinit)            |
     |*Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-1-amd64 (recovery mode)       |
     |                                                                            |
     +----------------------------------------------------------------------------+  
  3. Select Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-1-amd64 (recovery mode)
  4. Press ctrl-x to reboot.
  5. After the system reboots, set a new root password.

    cumulus@switch:~$ sudo passwd
    Enter new UNIX password: 
    Retype new UNIX password: 
    passwd: password updated successfully
  6. Sync the /etc directory using btrfs, then reboot the system:

    cumulus@switch:~$ sudo btrfs filesystem sync /etc
    cumulus@switch:~$ sudo reboot -f
    Restarting the system.