Fix setting default maintenance exclusion in GKE

Author: karagieseking

google/_modules/gke/cluster.tf

@@ -74,7 +74,7 @@ resource "google_container_cluster" "current" {
     }
 
     dynamic "maintenance_exclusion" {
-      for_each = var.maintenance_exclusion_start_time != null ? [1] : []
+      for_each = var.maintenance_exclusion_start_time != "" ? [1] : []
 
       content {
         start_time     = var.maintenance_exclusion_start_time

google/cluster/configuration.tf

@@ -31,10 +31,10 @@ locals {
     "03:00",
   )
 
-  cluster_maintenance_exclusion_start_time = lookup(local.cfg, "cluster_maintenance_exclusion_start_time", "")
-  cluster_maintenance_exclusion_end_time = lookup(local.cfg, "cluster_maintenance_exclusion_end_time", "")
-  cluster_maintenance_exclusion_name = lookup(local.cfg, "cluster_maintenance_exclusion_name", "")
-  cluster_maintenance_exclusion_scope = lookup(local.cfg, "cluster_maintenance_exclusion_scope", "")
+  cluster_maintenance_exclusion_start_time = lookup(local.cfg, "cluster_maintenance_exclusion_start_time", null)
+  cluster_maintenance_exclusion_end_time   = lookup(local.cfg, "cluster_maintenance_exclusion_end_time", null)
+  cluster_maintenance_exclusion_name       = lookup(local.cfg, "cluster_maintenance_exclusion_name", null)
+  cluster_maintenance_exclusion_scope      = lookup(local.cfg, "cluster_maintenance_exclusion_scope", null)
 
   remove_default_node_pool = lookup(local.cfg, "remove_default_node_pool", true)