How to recover server access if your user password is lost

Unless you intend to configure the server's disks in a way that requires them to be detached (unmounted), you need to first mount the system partition in order to access your data from rescue mode.

Firstly, list all partitions to retrieve the name of the partition you need to mount:

lsblk

Output examples:

NAME      MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda         8:0    0  1.8T  0 disk
├─sda1      8:1    0  511M  0 part
├─sda2      8:2    0  1.8T  0 part
│ └─md127   9:127  0  1.8T  0 raid1
├─sda3      8:3    0  512M  0 part
└─sda4      8:4    0    2M  0 part
sdb         8:16   0  1.8T  0 disk
├─sdb1      8:17   0  511M  0 part
├─sdb2      8:18   0  1.8T  0 part
│ └─md127   9:127  0  1.8T  0 raid1
└─sdb3      8:19   0  512M  0 part

NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
nvme1n1     259:0    0 894.3G  0 disk
├─nvme1n1p1 259:2    0   511M  0 part
├─nvme1n1p2 259:3    0     1G  0 part
│ └─md2       9:2    0  1022M  0 raid1
├─nvme1n1p3 259:4    0 892.3G  0 part
│ └─md3       9:3    0 892.1G  0 raid1
└─nvme1n1p4 259:5    0   512M  0 part
nvme0n1     259:1    0 894.3G  0 disk
├─nvme0n1p1 259:6    0   511M  0 part
├─nvme0n1p2 259:7    0     1G  0 part
│ └─md2       9:2    0  1022M  0 raid1
├─nvme0n1p3 259:8    0 892.3G  0 part
│ └─md3       9:3    0 892.1G  0 raid1
├─nvme0n1p4 259:9    0   512M  0 part
└─nvme0n1p5 259:10   0     2M  0 part

Then mount the pertinent partition accordingly:

mount /dev/PARTITION_NAME /MOUNT_POINT/

The partition to mount should be easily identifiable by the SIZE indicated in the table (sda2 in the first example, nvme1n1p3 in the second). Using the folder name mnt as mount point, for the first example the mount command would therefore be as follows:

mount /dev/md127 /mnt/

Command to enter for the second example:

mount /dev/md3 /mnt/

To see more technical information about the server's disks and partitions, enter:

fdisk -l

Some tasks may require that disks or partitions be detached. To do this, use the unmount command:

umount /mnt

Once you have successfully accessed your VPS via SSH, the first step will be to mount the partition to the Rescue Mode environment. We can find out which partition we need to mount using the following command:

# lsblk

Here is a sample output of this command:

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0  2.5G  0 disk 
└─sda1   8:1    0  2.5G  0 part /
sdb      8:16   0   20G  0 disk 
├─sdb1   8:17   0 19.9G  0 part 
├─sdb14  8:30   0    4M  0 part 
└─sdb15  8:31   0  106M  0 part 

This VPS has 20 GB of storage space. That means that the partition we need to mount is sdb1 since it contains 19.9 GB of storage and thus, contains the Linux filesystem. This partition will be in the /dev directory by default.

After identifying the storage device, create a root directory within the /mnt directory, and then use the mount command to mount the partition to the Rescue Mode environment:

# mkdir /mnt/root

# mount /dev/sdb1 /mnt/root

Now, navigate to the newly mounted device and then use the chroot command to give yourself root access to the mounted filesystem:

# cd /mnt/root

# chroot /mnt/root

Now, we can change the root password using the following command:

# passwd

If you wish to change the password for a different user, just append the username to the end of the above command, and it will change the password for that user. If you don't specify a user, as we did above, you are changing the root password by default.

Exit Rescue Mode and reboot your server. If you did everything correctly, your new password will grant you access to your live server environment.