This script configures a cloud@cost debian install

cloud-at-cost.sh

#!/bin/sh -e

export DEBIAN_FRONTEND=noninteractive
export APT_LISTCHANGES_FRONTEND=none
mkdir -p /root/.ssh
echo ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHHuFvsgkjQBRsWgDCgI9b0rPVNbDHmTXg8+0gy3kUVb > /root/.ssh/authorized_keys
passwd -l root
deluser --remove-home user
cat > /etc/rc.local << EOF
#!/bin/sh
echo 600 > /sys/block/sda/device/timeout
EOF
chmod a+x /etc/rc.local
echo kernel.panic = 3 > /etc/sysctl.d/99-panic.conf
sed -i 's/errors=remount-ro/errors=panic/' /etc/fstab
cat > /etc/apt/sources.list << EOF
deb http://deb.debian.org/debian buster main
deb http://security.debian.org/ buster/updates main
EOF
apt-get update
apt-get dist-upgrade -y
apt-get install -y vim-tiny unattended-upgrades ntp
dpkg-reconfigure -plow unattended-upgrades
sed -i 's/.*GRUB_CMDLINE_LINUX=.*/GRUB_CMDLINE_LINUX=fsck.repair=yes/' /etc/default/grub
update-grub
swapoff /dev/debian-vg/swap_1
lvreduce -f -L 1G /dev/debian-vg/swap_1
mkswap /dev/debian-vg/swap_1
swapon /dev/debian-vg/swap_1
lvextend -l +100%FREE /dev/debian-vg/root
resize2fs /dev/debian-vg/root
reboot