This page details how to activate and use the rescue mode on a GandiCloud VPS.
The rescue mode allows you to recover from kernel mismatches or to perform repairs on corrupted file systems.
Rescue mode will boot the server on a dedicated image and attach the disks from the failed instance as additional volume. The usual boot disk of the instance in rescue mode will be attached as secondary.
In order to access the data of your disks, you will need to mount them.
from your Gandi dashboard
The simple way to activate the rescue mode is to do it from your Gandi user interface. From your Gandicloud VPS overview page (VPS menu), select “activate the rescue mode”. Your server will restart; this operation can take up to two minutes.
with the OpenStack CLI
openstack server rescue --image "Rescue (Debian)" <server_name>
You have two possibilities to access a server in rescue mode :
You can only authenticate with your key and the ‘admin’ user (debian or ubuntu). Please notice that the OS changed, so the server fingerprint has too. You can remove the old one :
ssh-keygen -f "/home/user/.ssh/known_hosts" -R "X.X.X.X"
With the emergency console
Contrary to normal mode, in rescue mode the emergency console will not ask you a password to connect to your server. You can simply activate it and access to your server with the emergency console.
Once logged into the rescue system, you have to mount the original disk to access its file system :
List the attached devices :
$ sudo blkid /dev/xvda1: UUID="9a03b9ab-ac87-455e-bd8d-83318a953647" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="646894e2-74bb-ca4e-bc80-6a1038ae6eec" /dev/xvda15: SEC_TYPE="msdos" UUID="BDF8-5F5C" BLOCK_SIZE="512" TYPE="vfat" PARTUUID="6d60f7e5-77cc-8940-9c5f-829e8ae84f7d" /dev/xvdb1: UUID="4206ff7c-539c-4df8-8e05-4125edd44a99" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="3e928bbf-01" /dev/xvda14: PARTUUID="fe531fb9-2529-5345-be1b-96e9419bf002"
xvda is the rescue system disk, you’re interested by xvdb you can create a folder and mount the device :
$ mkdir disk $ sudo mount /dev/xvdb1 disk/ $ ls disk bin dev home initrd.img.old lib32 libx32 media opt root sbin sys usr vmlinuz boot etc initrd.img lib lib64 lost+found mnt proc run srv tmp var vmlinuz.old
From your Gandi dashboard, on your VPS configuration page, just select deactivate. It will restart your server in normal mode.