diff --git a/5-app-infra/business_unit_1/development/main.tf b/5-app-infra/business_unit_1/development/main.tf
index d473670beb..4fbe40bddc 100644
--- a/5-app-infra/business_unit_1/development/main.tf
+++ b/5-app-infra/business_unit_1/development/main.tf
@@ -25,7 +25,7 @@ module "base_shared_gce_instance" {
   environment         = local.environment
   business_unit       = local.business_unit
   project_suffix      = "sample-base"
-  region              = var.instance_region
+  region              = coalesce(var.instance_region, local.default_region)
   remote_state_bucket = var.remote_state_bucket
 }
 
@@ -35,6 +35,6 @@ module "peering_gce_instance" {
   environment         = local.environment
   business_unit       = local.business_unit
   project_suffix      = "sample-peering"
-  region              = var.instance_region
+  region              = coalesce(var.instance_region, local.default_region)
   remote_state_bucket = var.remote_state_bucket
 }
diff --git a/5-app-infra/business_unit_1/development/remote.tf b/5-app-infra/business_unit_1/development/remote.tf
new file mode 100644
index 0000000000..2120b289d0
--- /dev/null
+++ b/5-app-infra/business_unit_1/development/remote.tf
@@ -0,0 +1,28 @@
+/**
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+locals {
+  default_region = data.terraform_remote_state.bootstrap.outputs.common_config.default_region
+}
+
+data "terraform_remote_state" "bootstrap" {
+  backend = "gcs"
+
+  config = {
+    bucket = var.remote_state_bucket
+    prefix = "terraform/bootstrap/state"
+  }
+}
diff --git a/5-app-infra/business_unit_1/development/variables.tf b/5-app-infra/business_unit_1/development/variables.tf
index 8e9bafd0ae..8aa99e86cb 100644
--- a/5-app-infra/business_unit_1/development/variables.tf
+++ b/5-app-infra/business_unit_1/development/variables.tf
@@ -17,6 +17,7 @@
 variable "instance_region" {
   description = "The region where compute instance will be created. A subnetwork must exists in the instance region."
   type        = string
+  default     = null
 }
 
 variable "remote_state_bucket" {
diff --git a/5-app-infra/business_unit_1/non-production/main.tf b/5-app-infra/business_unit_1/non-production/main.tf
index 7c707ab7a2..e5f5675085 100644
--- a/5-app-infra/business_unit_1/non-production/main.tf
+++ b/5-app-infra/business_unit_1/non-production/main.tf
@@ -25,7 +25,7 @@ module "base_shared_gce_instance" {
   environment         = local.environment
   business_unit       = local.business_unit
   project_suffix      = "sample-base"
-  region              = var.instance_region
+  region              = coalesce(var.instance_region, local.default_region)
   remote_state_bucket = var.remote_state_bucket
 }
 
@@ -35,6 +35,6 @@ module "peering_gce_instance" {
   environment         = local.environment
   business_unit       = local.business_unit
   project_suffix      = "sample-peering"
-  region              = var.instance_region
+  region              = coalesce(var.instance_region, local.default_region)
   remote_state_bucket = var.remote_state_bucket
 }
diff --git a/5-app-infra/business_unit_1/non-production/remote.tf b/5-app-infra/business_unit_1/non-production/remote.tf
new file mode 100644
index 0000000000..2120b289d0
--- /dev/null
+++ b/5-app-infra/business_unit_1/non-production/remote.tf
@@ -0,0 +1,28 @@
+/**
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+locals {
+  default_region = data.terraform_remote_state.bootstrap.outputs.common_config.default_region
+}
+
+data "terraform_remote_state" "bootstrap" {
+  backend = "gcs"
+
+  config = {
+    bucket = var.remote_state_bucket
+    prefix = "terraform/bootstrap/state"
+  }
+}
diff --git a/5-app-infra/business_unit_1/non-production/variables.tf b/5-app-infra/business_unit_1/non-production/variables.tf
index 8e9bafd0ae..8aa99e86cb 100644
--- a/5-app-infra/business_unit_1/non-production/variables.tf
+++ b/5-app-infra/business_unit_1/non-production/variables.tf
@@ -17,6 +17,7 @@
 variable "instance_region" {
   description = "The region where compute instance will be created. A subnetwork must exists in the instance region."
   type        = string
+  default     = null
 }
 
 variable "remote_state_bucket" {
diff --git a/5-app-infra/business_unit_1/production/main.tf b/5-app-infra/business_unit_1/production/main.tf
index 544c94213c..40b488e899 100644
--- a/5-app-infra/business_unit_1/production/main.tf
+++ b/5-app-infra/business_unit_1/production/main.tf
@@ -25,7 +25,7 @@ module "base_shared_gce_instance" {
   environment         = local.environment
   business_unit       = local.business_unit
   project_suffix      = "sample-base"
-  region              = var.instance_region
+  region              = coalesce(var.instance_region, local.default_region)
   remote_state_bucket = var.remote_state_bucket
 }
 
@@ -35,6 +35,6 @@ module "peering_gce_instance" {
   environment         = local.environment
   business_unit       = local.business_unit
   project_suffix      = "sample-peering"
-  region              = var.instance_region
+  region              = coalesce(var.instance_region, local.default_region)
   remote_state_bucket = var.remote_state_bucket
 }
diff --git a/5-app-infra/business_unit_1/production/remote.tf b/5-app-infra/business_unit_1/production/remote.tf
new file mode 100644
index 0000000000..2120b289d0
--- /dev/null
+++ b/5-app-infra/business_unit_1/production/remote.tf
@@ -0,0 +1,28 @@
+/**
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+locals {
+  default_region = data.terraform_remote_state.bootstrap.outputs.common_config.default_region
+}
+
+data "terraform_remote_state" "bootstrap" {
+  backend = "gcs"
+
+  config = {
+    bucket = var.remote_state_bucket
+    prefix = "terraform/bootstrap/state"
+  }
+}
diff --git a/5-app-infra/business_unit_1/production/variables.tf b/5-app-infra/business_unit_1/production/variables.tf
index 8e9bafd0ae..8aa99e86cb 100644
--- a/5-app-infra/business_unit_1/production/variables.tf
+++ b/5-app-infra/business_unit_1/production/variables.tf
@@ -17,6 +17,7 @@
 variable "instance_region" {
   description = "The region where compute instance will be created. A subnetwork must exists in the instance region."
   type        = string
+  default     = null
 }
 
 variable "remote_state_bucket" {
diff --git a/5-app-infra/common.auto.example.tfvars b/5-app-infra/common.auto.example.tfvars
index 7f83f05b60..8ba24df06a 100644
--- a/5-app-infra/common.auto.example.tfvars
+++ b/5-app-infra/common.auto.example.tfvars
@@ -14,6 +14,6 @@
  * limitations under the License.
  */
 
-instance_region = "us-central1" // should be one of the regions used to create network on step 3-networks
+# instance_region = "us-central1" // should be one of the regions used to create network on step 3-networks
 
 remote_state_bucket = "REMOTE_STATE_BUCKET"