Recover Password

This section describes how to reset a lost password.

Boot the router into ONIE Rescue mode.

a. Power cycle the router and press the Esc key to enter the SONiC GRUB mode.

GNU GRUB version 2.02
 +----------------------------------------------------------------------------+
 |*SONiC-OS-azure_Cisco_202012.105636                                         |
 | ONIE                                                                       |
 |                                                                            |
 |                                                                            |
 |                                                                            |
 |                                                                            |
 |                                                                            |
 +----------------------------------------------------------------------------+
    Use the ^ and v keys to select which entry is highlighted.
    Press enter to boot the selected OS, `e' to edit the commands
    before booting or `c' for a command-line.

b. Select ONIE and press the Enter key.

c. Select ONIE: Rescue from the list of options.

GNU GRUB version 2.02
 +----------------------------------------------------------------------------+
 | ONIE: Install OS                                                           |
 |*ONIE: Rescue                                                               |
 | ONIE: Uninstall OS                                                         |
 | ONIE: Update ONIE                                                          |
 | ONIE: Embed ONIE                                                           |
 |                                                                            |
 |                                                                            |
 |                                                                            |
 +----------------------------------------------------------------------------+
    Use the ^ and v keys to select which entry is highlighted.
    Press enter to boot the selected OS, `e' to edit the commands
    before booting or `c' for a command-line.

Note: If you select Install OS, ONIE might update the boot order and the router will boot into the successive GRUB menu bypassing the option to boot into the SONiC partition. You may have to use the efibootmgr command from ONIE to change the boot order back to SONiC as the first option.

The router enters the ONIE Rescue mode.

Mount the SONiC partition.

a. Check the disk partitions where SONiC is installed.

ONIE:/ # parted -l
Model: ATA Micron_5300_MTFD (scsi)
Disk /dev/sda: 128GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number     Start      End       Size       File system       Name           Flags
 1         1049kB     269MB     268MB      fat16             EFI System     boot, hidden
 2         269MB      404MB     134MB      ext4              ONIE-BOOT      hidden
 3         404MB      34.8GB    34.4GB     ext4              SONiC-OS

In the example, SONiC is installed on the third partition of the disk /dev/sda location. So, mount the /dev/sda3 partition to update the password file.

b. Create a folder to mount the SONiC partition. In this example, you create sonic_recovery folder.

ONIE:/ # mkdir /mnt/sonic_recovery

c. Mount the SONiC partition to the sonic_recovery folder.

ONIE:/ # mount -t ext4 /dev/sda3 /mnt/sonic_recovery

Remove the password.

a. Enter the SONiC partition folder.

ONIE:/ # cd /mnt/sonic_recovery

b. View the files mounted in the /dev/sda3 partition.

ONIE:/mnt/sonic_recovery # ls -al
 drwxr-xr-x 9 root 0 4096 Apr 5 07:34 .
 drwxr-xr-x 5 root 0 100 Apr 5 07:52 ..
 drwxr-xr-x 2 root 0 4096 Mar 30 20:42 disk-img
 drwxr-xr-x 5 root 0 4096 Mar 30 20:40 grub
 drwxr-xr-x 8 root 0 4096 Mar 31 20:42 image-azure-cisco_202012.105636
 drwx------ 2 root 0 16384 Apr 1 20:39 lost+found
 -rw-r--r-- 1 root 0 854 Apr 2 20:40 machine.conf
 drwxr-xr-x 4 root 0 4096 Apr 2 13:20 reboot-cause
 drwxr-xr-x 3 root 0 4096 Apr 2 20:44 warmboot

c. Enter the directory where the SONiC image is saved, and then enter the /etc subdirectory.

ONIE:/mnt/sonic_recovery # cd image-azure_cisco_202012.10563
ONIE:/mnt/sonic_recovery/image-azure_cisco_202012.10563 # cd rw
ONIE:/mnt/sonic_recovery/image-azure_cisco_202012.10563/rw # cd etc
ONIE:/mnt/sonic_recovery/image-azure_cisco_202012.10563/rw/etc # ls
adjtime group ld.so.cache network passwd- ssh
cron.d gshadow linuxptp nsswitch.conf profile.d sysctl.d
default gshadow- machine-id nsswitch.conf.old rsyslog.conf systemd
dhcp hostname modprobe.d ntp.conf shadow
tacplus_nss.conf
ebtables.filter hosts modules-load.d pam.d shadowgroup
hosts.old mtab passwd sonic

The shadow file is the password file.

d. Search the username for which you want to recover the password. In this example, you recover the password for the username cisco.

ONIE:/mnt/sonic_recovery/image-azure_cisco_202012.10563/rw/etc # ls -al | grep shadow
  -rw-r----- 1 root 42 603 Apr 5 14:28 gshadow
  -rw-r----- 1 root 42 581 Apr 5 21:04 gshadow
  -rw------- 1 root 42 860 Apr 5 14:28 gshadow
  -rw------- 1 root 42 828 Apr 5 21:04 gshadow
  ONIE:/mnt/sonic_recovery/image-azure_cisco_202012.10563/rw/etc # grep cisco shadow
  cisco:6$sjaIDBUmsklcsnnTUYt/sdfkjKGDWFLdnlakkjbbjXAD1:19262:0:99999:7:::

e. Remove the password for the cisco username using vi shadow command. Alternatively, you can also use the sed command. Delete the characters between the first and the second colon symbol (:). In this example, the password 6$sjaIDBUmsklcsnnTUYt/sdfkjKGDWFLdnlakkjbbjXAD1 between the first and second colon symbols is removed as displayed in step 3d.

cisco::19262:0:99999:7:::

After you delete the password, use the wq command to save the file and quit the mode. The ONIE prompt is displayed.

Reboot the router.

ONIE:/mnt/sonic_recovery/image-azure_cisco_202012.10563/rw/etc # reboot

Select the SONiC image from the GRUB mode, and press the Enter key.

Enter the username and set a new password.

Last login: Wed Apr 6 18:52:14 UTC 2020 on ttyS0
Linux sonic 4.19.0-9-cisco-amd64 #1 SMP Debian 4.19.118-2+deb10u1 (2020-06-07) x86_64
You are on
 ____   ___  _   _ _  ____
/ ___| / _ \| \ | (_)/ ___|
\___ \| | | | \| | | |
 ___) | |_| | |\ | | |___
|____/ \___/|_| \_|_|\____|

-- Software for Open Networking in the Cloud --
Unauthorized access and/or use are prohibited.
All access and/or use are subject to monitoring.
Help: http://azure.github.io/SONiC/
sonic:~cisco
New password:
Retype new password:

The new password is updated successfully.