Variable of the prometheus metrics port.

defaults/main.yml

@@ -36,6 +36,7 @@ docker_log_to_journal: True
 docker_daemon_debug: False
 docker_prometheus_metrics: True
 docker_prometheus_host: 127.0.0.1
+docker_prometheus_metrics_port: 9323
 
 # Usage:
 # node.labels.<key_name>==<label_value>

templates/daemon.json.j2

@@ -16,7 +16,7 @@
 {% endif %}
 {% endif %}
 {% if docker_prometheus_metrics %}
-    "metrics-addr" : "{{ docker_prometheus_host }}:9323",
+    "metrics-addr" : "{{ docker_prometheus_host }}:{{ docker_prometheus_metrics_port }}",
     "experimental" : true,
 {% endif %}
 {% if docker_daemon_debug %}