Root Password Reset

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Revision as of 05:31, 11 March 2016 by Paul (talk | contribs)

The prgmr.com rescue image can be used to reset the root password for the vps similar to a rescue disk like tomsrtbt or the debian installer rescue mode. If you run netbsd, you can also boot the netbsd installer from the rescue disk for a similar process.

  1. If the vps (domain) is still running, shut it down using the Management Console.
    Name                                        ID   Mem VCPUs	State	Time(s)
    'build'                                 159   256     1     -b----     131.6
    
        Wiki at http://wiki.prgmr.com
        Please contact support@prgmr.com with any issues accessing your machine.
    
        Options for "cnrylefanu"
        1. out of band console (press ctrl-] to escape, not resizeable)
        2. create/start, opens OOB console (try this if the machine is not running)
        3. shutdown (requests operating system to shut down)
        4. force power off (destroy/hard shutdown)
        5. reboot (requests operating system to reboot)
        6. swap i386/amd64 bootloaders currently "amd64"
        7. view/add/remove ssh authorized_keys
        8. set reverse dns
        9. swap pvgrub/grub2 bootloaders currently "pv-grub"
    
        0. exit
        enter selection> 3
    
    
    This will signal the domain to shut down safely.
  2. When the machine is stopped, the Management Console menu will return. Pressing Enter will generate a new menu with a different heading:
    Domain 'build' is not running.
    
    which is normal, it just means the vps isn't running. Choose create/start to start the vps:
    Domain 'build' is not running.
    
        Wiki at http://wiki.prgmr.com
        Please contact support@prgmr.com with any issues accessing your machine.
    
        Options for "cnrylefanu"
        1. out of band console (press ctrl-] to escape, not resizeable)
        2. create/start, opens OOB console (try this if the machine is not running)
        3. shutdown (requests operating system to shut down)
        4. force power off (destroy/hard shutdown)
        5. reboot (requests operating system to reboot)
        6. swap i386/amd64 bootloaders currently "amd64"
        7. view/add/remove ssh authorized_keys
        8. set reverse dns
        9. swap pvgrub/grub2 bootloaders currently "pv-grub"
        0. exit
        enter selection> 2     
    

    The domain will start booting with pvgrub and will load the grub menu from the rescue image:

        GNU GRUB  version 0.97  (262144K lower / 0K upper memory)
    
     +-------------------------------------------------------------------------+
     | user bootloader configuration                                           |  
     | Debian GNU/Linux, kernel 3.16.0-4-amd64 Live Rescue                     |
     | Debian GNU/Linux, kernel 3.16.0-4-amd64 (single-user mode) Live Rescu>  |
     | centos5-64 rescue                                                       |
     | centos5-64 install                                                      |
     | centos6-64 rescue                                                       |
     | centos6-64 install                                                      |
     | centos7-64 rescue                                                       |
     | centos7-64 install                                                      |
     | debian-jessie-8.0-64 rescue                                             |
     | debian-jessie-8.0-64 install                                            |
     | debian-wheezy-7.0-64 rescue                                             | v
     +-------------------------------------------------------------------------+
        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.
    
  3. Choose Debian GNU/Linux Live Rescue to boot the read only rescue image. When it is finished booting, login as root at the prompt with no password:
    Debian GNU/Linux 8 rescue hvc0
    
    rescue login: root
    Linux rescue 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt20-1+deb8u3 (2016-01-17) x86_64
    Documentation on installing a new image is at 
    http://wiki.prgmr.com/mediawiki/index.php/Untarring_a_fresh_OS_image
    
    To enable ssh access to the rescue image, copy
    your public key to /root/.ssh/authorized_keys and type
    "service ssh start"
    root@rescue:~# 
    
  4. Mount your root filesystem (by default /dev/xvda1) and chroot to it:
    root@rescue:~# mount /dev/xvda1 /mnt
    [  330.620031] EXT4-fs (xvda1): mounting ext3 file system using the ext4 subsystem
    [  330.689992] EXT4-fs (xvda1): mounted filesystem with ordered data mode. Opts: (null)
    root@rescue:~# chroot /mnt
    [root@rescue /]# 
    
  5. Change the root password with passwd:
    [root@rescue /]# passwd
    Enter new UNIX password: 
    Retype new UNIX password: 
    passwd: password updated successfully
    [root@rescue /]# 
    
  6. Exit, unmount, and shutdown:
    [root@rescue /]# exit
    exit
    root@rescue:~# umount /mnt
    root@rescue:~# shutdown -h now
             Starting Synchronise Hardware Clock to System Clock...
    
  7. This will return you to the Management Console. Start the domain again as in step 2, but let it load the "user bootloader configuration" instead of choosing the rescue image.