auto br0
iface br0 inet static
  address  10.0.0.4
  netmask  255.255.255.0
  gateway  10.0.0.255
  pre-up   ip link add name $IFACE type bridge
{% for i in range(1, 4) %}

auto eth{{i}}
iface eth{{i}} inet manual
  up       ip link set $IFACE up
  post-up  ip addr flush dev $IFACE
  post-up  ip link set $IFACE master br0
{% endfor %}