nano /etc/network/interfaces.d/50-cloud-init

auto lo
iface lo inet loopback
dns-nameservers 213.186.33.99

auto eth0
iface eth0 inet dhcp
mtu 1500

auto eth0:1
iface eth0:1 inet static
address x.x.x.x
netmask 255.255.255.255

auto eth0:2
iface eth0:2 inet static
address x.x.x.x
netmask 255.255.255.255

auto eth0:3
iface eth0:3 inet static
address x.x.x.x
netmask 255.255.255.255