auto lo

iface lo inet loopback

auto eth0

iface eth0 inet static
  address {{ hostvars[inventory_hostname].ansible_default_ipv4.address }}
  netmask {{ hostvars[inventory_hostname].ansible_default_ipv4.netmask }}
  gateway {{ hostvars[inventory_hostname].ansible_default_ipv4.gateway }}

{% if ip6 is defined %}
iface eth0 inet6 static
  address {{ ip6 }}
  netmask {{ netmask6 }}
  gateway {{ gateway6 }}
  pre-up echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_ra
{% endif %}