ansible/roles/ifupdown2/templates/interfaces.j2

{{ ansible_managed | comment }}

{% for name, iface in ifupdown2__interfaces.items() %}
auto {{ name }}
iface {{ name }}
{% for address in iface.addresses %}
    address {{ address | ipaddr }}
{% endfor %}
{% for gateway in iface.gateways | default([]) %}
    gateway {{ gateway | ipaddr }}
{% endfor %}

{% endfor %}