startusingansible/examples/023_selective_removal/roles/nginx/templates/nginx.conf.j2

upstream {{ item.key }} {
{% for server in groups.webserver %}
    server {{ server }}:{{ item.value.backend }};
{% endfor %}
}

server {
    listen {{ item.value.frontend }};

    location / {
        proxy_pass http://{{ item.key }};
    }
}