src/servala/static/js/fqdn.js

@@ -23,9 +23,19 @@ const initializeFqdnGeneration = (prefix) => {
     if (!fqdnField) return
 
     if (nameField && fqdnField) {
+        const sanitizeForFqdn = (name) => {
+            return name
+                .toLowerCase()
+                .replace(/[^a-z0-9-]/g, '-')  // Replace invalid chars with hyphens
+                .replace(/-+/g, '-')           // Collapse multiple hyphens
+                .replace(/^-|-$/g, '');        // Trim hyphens from start/end
+        }
+
         const generateFqdn = (instanceName) => {
             if (!instanceName) return '';
-            return `${instanceName}-${fqdnConfig.namespace}.${fqdnConfig.wildcardDns}`;
+            const sanitized = sanitizeForFqdn(instanceName);
+            if (!sanitized) return ''
+            return `${sanitized}-${fqdnConfig.namespace}.${fqdnConfig.wildcardDns}`;
         }
 
         nameField.addEventListener('input', function() {