lb.yml

---
common_packages_install:
  - avahi-daemon
nginx_site_configs:
  app:
    servers:
      - listen: 80
        locations:
          - access_log: "{{ nginx_log_dir }}/app/access.log upstream"
            proxy_pass: "http://app"
            # proxy_set_headers:
            #   X-MOCK-UPSTREAM-HOST: $upstream_addr
            uri: "/"
    upstreams:
      app:
        servers:
          - "{{ hostvars['ansible-demo-app0']['ansible_eth1']['ipv4']['address'] }}:8484"
          - "{{ hostvars['ansible-demo-app1']['ansible_eth1']['ipv4']['address'] }}:8484"
secure_iptables_accept_avahi: true
secure_iptables_accept_http: true

site.conf.j2

# {{ ansible_managed }}
{% for upstream_key, upstream_value in item.value.upstreams.iteritems() %}

upstream {{ upstream_key }} {
{%  for server in upstream_value.servers %}
    server {{ server }};
{%  endfor %}
}
{% endfor %}
{% for server in item.value.servers %}

server {
    listen {{ server.listen }};
{%  for location in server.locations %}

    location {{ location.uri }} {
{%      if location.access_log | default() %}
        access_log {{ location.access_log }};
{%      endif %}
{%      if location.proxy_pass | default() %}
        proxy_pass {{ location.proxy_pass }};
{%      endif %}
{%      if location.proxy_set_headers is defined %}
        {%  for proxy_set_header_key, proxy_set_header_value in location.proxy_set_headers.iteritems() -%}
                proxy_set_header {{ proxy_set_header_key }} {{ proxy_set_header_value }};
{%          endfor %}
{%      endif %}
    }
{%  endfor %}
}
{% endfor %}