IcingaHost(Legacy): Render alias with renderLegacyCustomExtensions

refs #12919

library/Director/Objects/IcingaHost.php

@@ -342,6 +342,17 @@ class IcingaHost extends IcingaObject
         return c1::renderKeyValue('display_name', $this->display_name);
     }
 
+    protected function renderLegacyCustomExtensions()
+    {
+        $str = parent::renderLegacyCustomExtensions();
+
+        if (($alias = $this->vars()->get('alias')) !== null) {
+            $str .= c1::renderKeyValue('alias', $alias->getValue());
+        }
+
+        return $str;
+    }
+
     public static function loadWithApiKey($key, Db $db)
     {
         $query = $db->getDbAdapter()

library/Director/Objects/IcingaObject.php

@@ -2007,6 +2007,11 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
         return '';
     }
 
+    protected function renderLegacyCustomExtensions()
+    {
+        return '';
+    }
+
     protected function renderObjectHeader()
     {
         return sprintf(
@@ -2073,7 +2078,7 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
             //$this->renderRelatedSets(),
             $this->renderLegacyGroups(),
             //$this->renderMultiRelations(),
-            //$this->renderCustomExtensions(),
+            $this->renderLegacyCustomExtensions(),
             $this->renderLegacyCustomVars(),
             $this->renderLegacySuffix()
         ));