Add the prometheus directives to the daemon configuration

templates/daemon.json.j2

@@ -9,8 +9,14 @@
     "tlskey": "{{ docker_tls_key }}",
 {% if docker_tls_verify_clients %}
     "tlsverify": true,
+{% else %}
+    "tlsverify": false,
 {% endif %}
 {% endif %}
+{% if docker_prometheus_metrics %}
+    "metrics-addr" : "{{ docker_prometheus_host }}:9323",
+    "experimental" : true,
+{% endif %}
 {% if docker_daemon_debug %}
     "debug": true
 {% else %}