Install cloud-initramfs-rescuevol by entering the following commands in the terminal:
sudo apt update sudo apt install cloud-initramfs-rescuevol
boot off a rescue volume rather than root filesystem
This package adds functionality to an initramfs built by initramfs-tools. When installed the initramfs will check to see if any partitions with a label of 'RESCUE_VOL' are attached. If such a volume is attached, it will boot off that volume rather than the root volume. . This is useful in a cloud environment, when the user is able to attach and detach volumes to a running system, but has no other mechanism for interupting of fixing a failed boot. It is analogous to inserting a rescue CD into a system to recover from failure.