Manage backend firewall zone

Configure backend firewall zones if applicable. Allow all UDP for
cluster traffic.

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

pillar/global/init.sls

@@ -26,6 +26,10 @@ firewalld:
     public:
       short: Public
       {{ firewall_interfaces(public) }}
+    {%- if backend | length %}
+    backend:
+      {{ firewall_interfaces(backend) }}
+    {%- endif %}
 {%- endif %}
 
 mine_functions:

pillar/role/ha-node.sls

@@ -3,3 +3,6 @@ firewalld:
     internal:
       services:
         - vrrp
+    backend:
+      protocols:
+        - udp