Root Password Reset: Difference between revisions

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== Resetting the root account password on Debian (or any account password) ==
== Resetting the root account password on the PVE Host ==
This has been tested and is known to work with Debian versions 6, 7, and 8. It can also be used to change any account password.
 
The following follows the general method for resetting a root password on a Linux machine, if you have access to the console see e.g.:
* [https://www.debian.org/doc/manuals/debian-reference/ch04.en.html#_securing_the_root_password the Debian Handbook]
* [https://wiki.archlinux.org/title/Reset_lost_root_password the Arch Linux Wiki entry]
* [https://en.wikibooks.org/wiki/Linux_Guide/Reset_a_forgotten_root_password the entry in WikiBooks]
for similar suggestions.
 
Keep in mind that editing the kernel command-line might need a different key-entry based on your boot-loader (<code>e</code> works for both <code>grub</code> and <code>systemd-boot</code> though).
The method works for Proxmox VE until version 8.1 and should work for many other Linux based Operating systems as well:


=== Method 1 ===
=== Method 1 ===
* Boot into '''grub''', select '''''single user''''' but '''do not press enter'''.
* Boot into your bootloader (mostly <code>grub</code> or <code>systemd-boot</code>, select your preferred kernel but '''do not press enter'''.
* Press '''e''' to go into '''edit''' mode.
* Press '''e''' to go into '''edit''' mode.
* Scroll down to the '''kernel''' line, it starts with "<tt>linux /boot/vmlinuz-2.6…….</tt>"
* Depending on the boot-loader go to the kernel-commandline entry:
* Scroll to the end of that line and press '''space key''' once and type <tt>init=/bin/bash </tt>
** For <code>grub</code>: scroll down to the <code>kernel</code> line you will boot from, it starts with <code>linux /vmlinuz-...</code>
* Press '''Ctrl X''' to boot
** For <code>systemd-boot</code> the kernel commandline is directly editable
* Scroll to the end of that line, optionally remove the <code>quiet</code> in the line and append <code> init=/bin/bash</code>
* For <code>grub</code> press <code>Ctrl X</code> to boot, for <code>systemd-boot</code> simply press Enter
 
In the resulting shell:
# Remount / as Read/Write
mount -o remount,rw /


<source lang="bash">
# Change the root account password with
# Remount / as Read/Write
passwd
mount -rw -o remount /


# Change the root account password with
# Change any other account password with
passwd
passwd username


# Change any other account password with
# type new password, confirm and hit enter and then reboot.
passwd username


# type new password, confirm and hit enter and then reboot.
</source>


=== Method 2 ===
=== Method 2 ===
* Boot from another installation of Debian. (One can use a LiveCD to get access to the "/" partition.)
* Boot from a Live CD, which supports the <code>/</code> filesystem of your PVE installation (mostly relevant for installs on ZFS) (e.g. a Proxmox install ISO, in debug-mode (second debug-shell))
* Then, mount the partition where you have Debian's "/" (root directory), then change directory to '''/mnt/etc'''
* Mount the <code>/</code> filesystem in read-write mode at a free directory (e.g.<code>/mnt</code> will be used in this example).
* Used '''vim / nano''' as an editor to edit the file '''shadow'''.
** you might need to do other steps, based on the filesystem, e.g. <code>zpool import -f -R /mnt rpool</code> for ZFS.
* Find the line starting with '''root:''' (or another username)
* Run <code>passwd -R /mnt</code> to set a new password for the <code>root</code> account.
* Delete everything between the first and second colons (:), and the line will now look like:
* Unmount/export the <code>/</code>-filesystem and reboot.
root::$6$fsdsdgdsg74.:14862:0:99999:7:::
* Reboot and login as '''root''' (or another username as used above) without a password.
* At the end use '''passwd''' to set a new password for the root account (or '''passwd username''' to change any account password).
* Reboot and login as '''root''' with the new root password.


=== Method for OpenVZ containers ===
== Resetting the root account password in a Container ==
* Enter the working container and change the password using:
* Enter the working container and change the password using:
<source lang="bash">
vzctl enter <VEID>
pct enter <VMID>
passwd <new password>
passwd
exit
# enter new password in silent prompt
</source>
exit
 
* If you're still using OpenVZ containers, which are not supported in Proxmox VE 4 or newer, you can use <code>vzctl enter <VEID></code> to enter the container.


== References ==
== References ==
* [http://derwynd.com/2011/04/14/debian-squeeze-change-root-password/ Debian Squeeze change root password]
* [http://c-nergy.be/blog/?p=1777 Griffon's IT Library] - [[Media:Debian-PVE-root-Password-Reset_pdf.zip|Cache]]
* [http://c-nergy.be/blog/?p=1777 Griffon's IT Library] - [[Media:Debian-PVE-root-Password-Reset_pdf.zip|Cache]]
* https://wiki.debian.org/Root
* https://wiki.debian.org/Root


[[Category: HOWTO]]
[[Category: HOWTO]] [[Category:System Administration]]

Latest revision as of 15:49, 22 January 2024

Resetting the root account password on the PVE Host

The following follows the general method for resetting a root password on a Linux machine, if you have access to the console see e.g.:

for similar suggestions.

Keep in mind that editing the kernel command-line might need a different key-entry based on your boot-loader (e works for both grub and systemd-boot though). The method works for Proxmox VE until version 8.1 and should work for many other Linux based Operating systems as well:

Method 1

  • Boot into your bootloader (mostly grub or systemd-boot, select your preferred kernel but do not press enter.
  • Press e to go into edit mode.
  • Depending on the boot-loader go to the kernel-commandline entry:
    • For grub: scroll down to the kernel line you will boot from, it starts with linux /vmlinuz-...
    • For systemd-boot the kernel commandline is directly editable
  • Scroll to the end of that line, optionally remove the quiet in the line and append init=/bin/bash
  • For grub press Ctrl X to boot, for systemd-boot simply press Enter

In the resulting shell: 

# Remount / as Read/Write 
mount -o remount,rw /

# Change the root account password with
passwd

# Change any other account password with
passwd username

# type new password, confirm and hit enter and then reboot.


Method 2

  • Boot from a Live CD, which supports the / filesystem of your PVE installation (mostly relevant for installs on ZFS) (e.g. a Proxmox install ISO, in debug-mode (second debug-shell))
  • Mount the / filesystem in read-write mode at a free directory (e.g./mnt will be used in this example).
    • you might need to do other steps, based on the filesystem, e.g. zpool import -f -R /mnt rpool for ZFS.
  • Run passwd -R /mnt to set a new password for the root account.
  • Unmount/export the /-filesystem and reboot.

Resetting the root account password in a Container

  • Enter the working container and change the password using:
pct enter <VMID>
passwd
# enter new password in silent prompt
exit
  • If you're still using OpenVZ containers, which are not supported in Proxmox VE 4 or newer, you can use vzctl enter <VEID> to enter the container.

References

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