unlock luks root using ssh
install dracut-sshd:
zypper in -y dracut-sshd
add network module to initram:
echo 'add_dracutmodules+=" network "' | tee /etc/dracut.conf.d/90-network.conf
setup network:
add this to cmdline (for grub use /etc/default/grub file):
ip=$IPADDRESS::$GATEWAY:$NETMASK:$HOSTNAME:$INTERFACENAME:off
add your ssh public key to one of this files:
/root/.ssh/dracut_authorized_keys
/etc/dracut-sshd/authorized_keys
/root/.ssh/authorized_keys
update initramfs & grub config:
/usr/bin/dracut -f -v
/usr/sbin/update-bootloader
reboot & try:
systemctl reboot
connect:
ssh root@$IPADDRESS
after connecting you will see this:
Welcome to the early boot SSH environment. You may type

 systemd-tty-ask-password-agent

(or press "arrow up") to unlock your disks.
This shell will terminate automatically a few seconds after the
unlocking process has succeeded and when the boot proceeds. 
initramfs-ssh:/root#
to unlock the partition you must type the following, press enter and enter the password:
systemd-tty-ask-password-agent
(in fact, just press the "up arrow" and enter in order to get a password request)
