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The Hetzner Rescue System
The Hetzner Rescue System is a Linux live environment that allows you to have administrative access to your server. The environment starts from the network (PXE boot) and runs in the memory of the server. This makes it possible to carry out repairs to the installed system, to check file systems or to install a new operating system.
Alternatively or additionally, you can use a LARA remote console.
Starting the Rescue System
Activating the Rescue System
To start a server in the Rescue System, it needs to be activated in the Robot.
Under "Main Functions; Server" select the desired server and then open the tab "Rescue". Here the desired variant can be activated.
The password that was given to you when you activated the Rescue System can now be used to login as "root" via SSH.
Restarting the Server
To load the Rescue System, the server must be restarted.
If you no longer have access to the server, you can use the reset function in the Robot. You will find this under the "Reset" tab of the desired server.
Please note that the activation of the Rescue System automatically becomes inactive after one hour. If the server is restarted later, the system will boot from the internal drive(s).
Mounting the Drive(s) in the Rescue System
Without Software Raid
You can display the detected drives.
ls /dev/[hsv]d[a-z]*[0-9]* # e.g. /dev/sda /dev/sda1 /dev/sda2 /dev/sda3
You can then mount the desired drive/partition.
mount /dev/sda3 /mnt
With Software Raid
You can display the detected MD devices.
ls /dev/md* # e.g. /dev/md0 /dev/md1 /dev/md2
You can then mount the desired MD device.
mount /dev/md2 /mnt
Mounting LVM Volumes
You can display the LVM Volumes.
ls /dev/mapper/* # e.g. /dev/mapper/vg0-home /dev/mapper/vg0-root /dev/mapper/vg0-swap
You can then mount the desired LVM volumes.
mount /dev/mapper/vg0-root /mnt
Resetting the Root Password
To reset the root password of the server, you must first mount the drives as explained in point 3.
Then use chroot to switch into the mounted system.
chroot-prepare /mnt chroot /mnt
You can now change the password directly by using passwd.
Installation of an Operating System
Hetzner Online GmbH offers a a comfortable menu-based script called installimage for installing an operating system. Information can be found in the installimage page.
Other Rescue Systems
In addition to the Linux-based Rescue System, Hetzner Online GmbH also offers other rescue systems.