Add default-server parameter in backend

net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/dialogBackend.xml

@@ -130,6 +130,12 @@
         <help><![CDATA[These lines will be added to the HAProxy backend configuration.<br/><div class="text-info"><b>NOTE:</b> The syntax will not be checked, use at your own risk!</div>]]></help>
         <advanced>true</advanced>
     </field>
+    <field>
+        <id>backend.tuning_defaultserver</id>
+        <label>Default for server</label>
+        <type>text</type>
+        <help><![CDATA[Default option for all server entries.]]></help>
+    </field>
     <field>
         <label>Actions (ACLs)</label>
         <type>header</type>

net/haproxy/src/opnsense/mvc/app/models/OPNsense/HAProxy/HAProxy.xml

@@ -476,6 +476,9 @@
                 <customOptions type="TextField">
                     <Required>N</Required>
                 </customOptions>
+                <tuning_defaultserver type="TextField">
+                    <Required>N</Required>
+                </tuning_defaultserver>
                 <linkedActions type="ModelRelationField">
                     <Model>
                         <template>

net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf

@@ -749,6 +749,9 @@ backend {{backend.name}}
     {{customOpt}}
 {%         endfor %}
 {%       endif %}
+{%       if backend.tuning_defaultserver|default("") != "" %}
+    default-server {{backend.tuning_defaultserver}}
+{%       endif %}
 
 {%       for server in backend.linkedServers.split(",") %}
 {%         set server_data = helpers.getUUID(server) %}