installs the stuff and does some config for a dracut-ssh-crypt like setup -- ssh into initramfs to unlock the luks partition

ubuntu-setup-remote-luks-unlock.sh

#!/usr/bin/env bash

# installs the stuff and does some config for a dracut-ssh-crypt like setup -- ssh into initramfs to unlock the luks partition

sudo apt install dropbear{,-initramfs}

DB_CONFIG=/etc/dropbear-initramfs/config
DB_AUTH_KEYS=/etc/dropbear-initramfs/authorized_keys

sudo mkdir -p /etc/dropbear-initramfs
sudo touch $DB_CONFIG

echo 'DROPBEAR_OPTIONS="-p 222 -s -j -k -I 60"' | sudo tee -a $DB_CONFIG

echo -n '' | sudo tee $DB_AUTH_KEYS
cat $HOME/.ssh/authorized_keys | sudo tee -a $DB_AUTH_KEYS
PREFIX='no-port-forwarding,no-agent-forwarding,no-x11-forwarding,command="/bin/cryptroot-unlock"'

sudo sed -i -e "s/^/no-port-forwarding,no-agent-forwarding,no-x11-forwarding,command=\"\/bin\/cryptroot-unlock\" /" $DB_AUTH_KEYS

sudo update-initramfs -u


# maybe, depending on setup
# add 'ip=dhcp' or 'ip=<clientip>::<gw-ip>:<netmask>' to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub
# afterwards don't forget to `update-grub`


# dope, ssh in on 222 during boot