haproxy.ctmpl

frontend superhero
    bind *:80
    # From my aws2json
    {{with $d := file "/tmp/aws.json" | parseJSON}}
    stats show-desc {{$d.instance_id}}
    {{end}}

    acl superman hdr(host) -i -m beg superman
    acl batman hdr(host) -i -m beg batman

    use_backend maintenance if {{if key "maintenance"}}TRUE{{else}}FALSE{{end}}

    use_backend superman if superman
    use_backend batman if batman

backend batman
    balance roundrobin check {{range service "batman"}}
    server {{.Node}} {{.Address}}:{{.Port}} maxconn 1000 {{end}}

backend superman
    balance roundrobin check {{range service "superman"}}
    server {{.Node}} {{.Address}}:{{.Port}} maxconn 1000 {{end}}