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-cl3u3
    
     +----------------------------------------------------------------------------+
     |*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-cl3u3
    
     +----------------------------------------------------------------------------+
     | Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-7-amd64                       | 
     |*Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-7-amd64 (recovery mode)       |
     |                                                                            |
     +----------------------------------------------------------------------------+  
  3. Select Cumulus Linux GNU/Linux, with Linux 4.1.0-cl-7-amd64 (recovery mode)
  4. Press ctrl-x to reboot.
  5. After the system reboots, set a new root password. This is useful since the root user provides complete control over the switch, and providing a new password now helps in case the current password has been forgotten, which is a common problem.

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

    You may want to take this opportunity to reset the password for the cumulus account as well.

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

    root@switch:~# btrfs filesystem sync /etc
    root@switch:~# reboot -f
    Restarting the system.