gistfile1.txt

{% for env_name, nodegroup in pillar.get('envs', {}).items() %}
    upstream {{env_name}}_backend {
        {% set targets = 'E@(n2|n3|n4)' %}
        {% for server, addrs in salt['mine.get'](targets, 'network.ip_addrs', expr_form='compound').items() %}
                {% if server in salt['pillar.get']('master:nodegroups:prod_appservers', []) %}
         server {{ addrs[0] }}:8123;
                {% endif %}
        {% endfor %}

       least_conn;
    }
{% endfor %}