Add missing default for grafana host
diff --git a/roles/kube_prometheus_stack/defaults/main.yml b/roles/kube_prometheus_stack/defaults/main.yml
index 47f2602..1052feb 100644
--- a/roles/kube_prometheus_stack/defaults/main.yml
+++ b/roles/kube_prometheus_stack/defaults/main.yml
@@ -22,6 +22,7 @@
kube_prometheus_stack_ingress_class_name: "{{ atmosphere_ingress_class_name }}"
kube_prometheus_stack_grafana_ingress_class_name: "{{ kube_prometheus_stack_ingress_class_name }}"
-# kube_prometheus_stack_grafana_host:
+
+kube_prometheus_stack_grafana_host: "{{ undef('You must specify a Grafana host using kube_prometheus_stack_grafana_host') }}"
kube_prometheus_stack_grafana_admin_password: "{{ undef('You must specify a Grafana password using kube_prometheus_stack_grafana_admin_password') }}"