Update DuckDNS subdomain with dynamic IP

roles/base/templates/duckdns.sh.j2

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+domains="{{ duckdns.domains }}"
+token="{{ duckdns.token }}"
+{% if duckdns.logfile is undefined -%}
+  log="/var/log/duckdns.log"
+{% else -%}
+  log="{{ duckdns.logfile }}"
+{% endif %}
+
+url="https://www.duckdns.org/update?domains=$domains&token=$token&ip="
+
+time=$(date '+%Y%m%d-%H%M%S')
+result=$(curl $url)
+
+if [ "$result" = "OK" ];  then
+  echo "[$time] OK" >> $log
+else
+  echo "[$time] ERROR: $result" >> $log
+fi