#Empiezo en Hetzner con una máquina Debian 9 tal cual.

#Actualizo los paquetes:

aptitude update ; aptitude upgrade -y

#Para migrar a Devuan sigo https://www.devuan.org/os/documentation/dev1fanboy/en/stretch-to-beowulf.html pero con mi propio estilo:

aptitude install sysvinit-core -y
aptitude purge --purge-unused libpam-systemd -y
sed -i 's/^deb/#deb/g' /etc/apt/sources.list
mv /etc/apt/sources.list.d/hetzner-mirror.list /etc/apt/sources.list.d/hetzner-mirror.listNO
mv /etc/apt/sources.list.d/hetzner-security-updates.list /etc/apt/sources.list.d/hetzner-security-updates.listNO
echo deb http://deb.devuan.org/merged beowulf main > /etc/apt/sources.list.d/devuan-beowulf.list
echo deb http://deb.devuan.org/merged beowulf-updates main >> /etc/apt/sources.list.d/devuan-beowulf.list
echo deb http://deb.devuan.org/merged beowulf-security main >> /etc/apt/sources.list.d/devuan-beowulf.list
echo "#deb http://deb.devuan.org/merged beowulf-backports main" >> /etc/apt/sources.list.d/devuan-beowulf.list
aptitude update
aptitude install devuan-keyring --allow-untrusted -y
aptitude update
aptitude install libtinfo6 -y
aptitude upgrade -y
sed -i '/does nothing/ a /etc/init.d/networking restart' /etc/rc.local
reboot
aptitude -y install eudev
aptitude -y full-upgrade
aptitude purge --purge-unused systemd -y
apt-get autoclean

#Con esto tengo una máquina Devuan perfectamente funcional en Hetzner.