cloud-initramfs-growroot

Description

automatically resize the root partition on first boot
This package adds functionality to an initramfs built by initramfs-tools.
When installed, the initramfs will repartition a disk to make the
root volume consume all space that follows it.

You most likely do not want this package unless you know what you are
doing.  It is primarily interesting in a virtualized environment when
a disk can provisioned with a size larger than its original size.
In this case, with this package installed, you can automatically use
the new space without requiring a reboot to re-read the partition table.