diff --git a/.github/labeler.yaml b/.github/labeler.yaml
index bb352d2..bc6b780 100644
--- a/.github/labeler.yaml
+++ b/.github/labeler.yaml
@@ -11,5 +11,8 @@
 ":floppy_disk: security-group":
 - modules/security-group/**/*
 
+":floppy_disk: subnet-group":
+- modules/subnet-group/**/*
+
 ":floppy_disk: vpc":
 - modules/vpc/**/*
diff --git a/examples/vpc-full/nat-gateways.tf b/examples/vpc-full/nat-gateways.tf
new file mode 100644
index 0000000..3df103c
--- /dev/null
+++ b/examples/vpc-full/nat-gateways.tf
@@ -0,0 +1,67 @@
+###################################################
+# Elastic IP
+###################################################
+
+module "elastic_ip" {
+  source  = "tedilabs/ipam/aws//modules/elastic-ip"
+  version = "~> 0.3.0"
+
+  name = "nat-gw-test-public/az2"
+  type = "AMAZON"
+
+  tags = {
+    "project" = "terraform-aws-network-examples"
+  }
+}
+
+
+###################################################
+# Public NAT Gateway
+###################################################
+
+module "public_nat_gateway" {
+  source = "../../modules/nat-gateway"
+  # source  = "tedilabs/network/aws//modules/nat-gateway"
+  # version = "~> 0.2.0"
+
+  name       = "test-public/az2"
+  is_private = false
+  subnet     = module.public_subnet_group.subnets_by_az["use1-az2"][0].id
+
+
+  ## Primary IP Address
+  primary_ip_assignment = {
+    elastic_ip = module.elastic_ip.id
+  }
+
+
+  tags = {
+    "project" = "terraform-aws-network-examples"
+  }
+}
+
+
+###################################################
+# Private NAT Gateway
+###################################################
+
+module "private_nat_gateway" {
+  source = "../../modules/nat-gateway"
+  # source  = "tedilabs/network/aws//modules/nat-gateway"
+  # version = "~> 0.2.0"
+
+  name       = "test-private/az2"
+  is_private = true
+  subnet     = module.private_subnet_group.subnets_by_az["use1-az2"][0].id
+
+
+  ## Primary IP Address
+  primary_ip_assignment = {
+    private_ip = "10.0.200.7"
+  }
+
+
+  tags = {
+    "project" = "terraform-aws-network-examples"
+  }
+}
diff --git a/examples/vpc-full/outputs.tf b/examples/vpc-full/outputs.tf
index cc46043..6bd50a8 100644
--- a/examples/vpc-full/outputs.tf
+++ b/examples/vpc-full/outputs.tf
@@ -2,3 +2,21 @@ output "vpc" {
   description = "The VPC."
   value       = module.vpc
 }
+
+output "subnet_groups" {
+  description = "The Subnet Groups for the VPC."
+  value = {
+    private = module.private_subnet_group
+    public  = module.public_subnet_group
+  }
+}
+
+output "public_nat_gateways" {
+  description = "The NAT Gateways in public."
+  value       = module.public_nat_gateway
+}
+
+output "private_nat_gateways" {
+  description = "The NAT Gateways in private."
+  value       = module.private_nat_gateway
+}
diff --git a/examples/vpc-full/subnet-groups.tf b/examples/vpc-full/subnet-groups.tf
new file mode 100644
index 0000000..868f46a
--- /dev/null
+++ b/examples/vpc-full/subnet-groups.tf
@@ -0,0 +1,138 @@
+###################################################
+# Subnet Groups
+###################################################
+
+module "private_subnet_group" {
+  source = "../../modules/subnet-group"
+  # source  = "tedilabs/network/aws//modules/subnet-group"
+  # version = "~> 0.2.0"
+
+  name = "test/private"
+
+  vpc_id = module.vpc.id
+
+  subnets = {
+    "test/private/az2" = {
+      availability_zone_id = "use1-az2"
+      ipv4_cidr            = "10.0.200.0/24"
+    }
+    "test/private/az4" = {
+      availability_zone_id = "use1-az4"
+      ipv4_cidr            = "10.0.201.0/24"
+    }
+  }
+
+
+  ## IP Assignments
+  public_ipv4_address_assignment = {
+    enabled = false
+  }
+  ipv6_address_assignment = {
+    enabled = false
+  }
+  customer_owned_ipv4_address_assignment = {
+    enabled = false
+  }
+
+
+  ## DNS Configurations
+  dns_config = {
+    hostname_type                  = "RESOURCE_NAME"
+    dns_resource_name_ipv4_enabled = true
+    dns_resource_name_ipv6_enabled = false
+    dns64_enabled                  = false
+  }
+
+  ## Integrations
+  dax_subnet_group = {
+    enabled     = true
+    name        = "test-dax"
+    description = "Test DAX Subnet Group"
+  }
+  dms_replication_subnet_group = {
+    enabled     = true
+    name        = "test-dms-replication"
+    description = "Test DMS Replication Subnet Group"
+  }
+  docdb_subnet_group = {
+    enabled     = true
+    name        = "test-docdb"
+    description = "Test DocumentDB Subnet Group"
+  }
+  elasticache_subnet_group = {
+    enabled     = true
+    name        = "test-elasticache"
+    description = "Test ElastiCache Subnet Group"
+  }
+  memorydb_subnet_group = {
+    enabled     = true
+    name        = "test-memorydb"
+    description = "Test MemoryDB Subnet Group"
+  }
+  neptune_subnet_group = {
+    enabled     = true
+    name        = "test-neptune"
+    description = "Test Neptune Subnet Group"
+  }
+  rds_subnet_group = {
+    enabled     = true
+    name        = "test-rds"
+    description = "Test RDS Subnet Group"
+  }
+  redshift_subnet_group = {
+    enabled     = true
+    name        = "test-redshift"
+    description = "Test Redshift Subnet Group"
+  }
+
+  tags = {
+    "project" = "terraform-aws-network-examples"
+  }
+}
+
+module "public_subnet_group" {
+  source = "../../modules/subnet-group"
+  # source  = "tedilabs/network/aws//modules/subnet-group"
+  # version = "~> 0.2.0"
+
+  name = "test/public"
+
+  vpc_id = module.vpc.id
+
+  subnets = {
+    "test/public/az2" = {
+      availability_zone_id = "use1-az2"
+      ipv4_cidr            = "10.0.100.0/24"
+    }
+    "test/public/az4" = {
+      availability_zone_id = "use1-az4"
+      ipv4_cidr            = "10.0.101.0/24"
+    }
+  }
+
+
+  ## IP Assignments
+  public_ipv4_address_assignment = {
+    enabled = true
+  }
+  ipv6_address_assignment = {
+    enabled = false
+  }
+  customer_owned_ipv4_address_assignment = {
+    enabled = false
+  }
+
+
+  ## DNS Configurations
+  dns_config = {
+    hostname_type                  = "RESOURCE_NAME"
+    dns_resource_name_ipv4_enabled = true
+    dns_resource_name_ipv6_enabled = false
+    dns64_enabled                  = false
+  }
+
+
+  tags = {
+    "project" = "terraform-aws-network-examples"
+  }
+}
diff --git a/modules/subnet-group/README.md b/modules/subnet-group/README.md
index b7f4c59..662fd10 100644
--- a/modules/subnet-group/README.md
+++ b/modules/subnet-group/README.md
@@ -3,13 +3,14 @@
 This module creates following resources.
 
 - `aws_subnet`
+- `aws_dax_subnet_group` (optional)
 - `aws_db_subnet_group` (optional)
+- `aws_dms_replication_subnet_group` (optional)
+- `aws_docdb_subnet_group` (optional)
 - `aws_elasticache_subnet_group` (optional)
-- `aws_redshift_subnet_group` (optional)
+- `aws_memorydb_subnet_group` (optional)
 - `aws_neptune_subnet_group` (optional)
-- `aws_docdb_subnet_group` (optional)
-- `aws_dax_subnet_group` (optional)
-- `aws_dms_replication_subnet_group` (optional)
+- `aws_redshift_subnet_group` (optional)
 
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements
@@ -23,7 +24,7 @@ This module creates following resources.
 
 | Name | Version |
 |------|---------|
-| <a name="provider_aws"></a> [aws](#provider\_aws) | 5.19.0 |
+| <a name="provider_aws"></a> [aws](#provider\_aws) | 5.22.0 |
 
 ## Modules
 
@@ -44,40 +45,34 @@ This module creates following resources.
 | [aws_neptune_subnet_group.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/neptune_subnet_group) | resource |
 | [aws_redshift_subnet_group.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/redshift_subnet_group) | resource |
 | [aws_subnet.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/subnet) | resource |
+| [aws_availability_zones.available](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zones) | data source |
 
 ## Inputs
 
 | Name | Description | Type | Default | Required |
 |------|-------------|------|---------|:--------:|
-| <a name="input_name"></a> [name](#input\_name) | The name of the subnet group. | `string` | n/a | yes |
-| <a name="input_subnets"></a> [subnets](#input\_subnets) | A map of subnet parameters to create subnets for the subnet group. | `map(map(any))` | n/a | yes |
-| <a name="input_vpc_id"></a> [vpc\_id](#input\_vpc\_id) | The ID of the VPC which the subnet group belongs to. | `string` | n/a | yes |
-| <a name="input_assign_ipv6_address_on_creation"></a> [assign\_ipv6\_address\_on\_creation](#input\_assign\_ipv6\_address\_on\_creation) | Assign IPv6 address on subnet, must be disabled to change IPv6 CIDRs. This is the IPv6 equivalent of map\_public\_ip\_on\_launch. | `bool` | `false` | no |
-| <a name="input_cache_subnet_group_enabled"></a> [cache\_subnet\_group\_enabled](#input\_cache\_subnet\_group\_enabled) | Controls if Elasticache Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_cache_subnet_group_name"></a> [cache\_subnet\_group\_name](#input\_cache\_subnet\_group\_name) | Desired name for the Elasticache Subnet Group. | `string` | `""` | no |
-| <a name="input_customer_owned_ipv4_pool"></a> [customer\_owned\_ipv4\_pool](#input\_customer\_owned\_ipv4\_pool) | The customer owned IPv4 address pool. `outpost_arn` argument must be specified when configured. | `string` | `""` | no |
-| <a name="input_dax_subnet_group_enabled"></a> [dax\_subnet\_group\_enabled](#input\_dax\_subnet\_group\_enabled) | Controls if DAX Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_dax_subnet_group_name"></a> [dax\_subnet\_group\_name](#input\_dax\_subnet\_group\_name) | Desired name for the DAX Subnet Group. | `string` | `""` | no |
-| <a name="input_db_subnet_group_enabled"></a> [db\_subnet\_group\_enabled](#input\_db\_subnet\_group\_enabled) | Controls if RDS Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_db_subnet_group_name"></a> [db\_subnet\_group\_name](#input\_db\_subnet\_group\_name) | Desired name for the RDS Subnet Group. | `string` | `""` | no |
-| <a name="input_dms_replication_subnet_group_enabled"></a> [dms\_replication\_subnet\_group\_enabled](#input\_dms\_replication\_subnet\_group\_enabled) | Controls if DMS Replication Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_dms_replication_subnet_group_name"></a> [dms\_replication\_subnet\_group\_name](#input\_dms\_replication\_subnet\_group\_name) | Desired name for the DMS Replication Subnet Group. | `string` | `""` | no |
-| <a name="input_docdb_subnet_group_enabled"></a> [docdb\_subnet\_group\_enabled](#input\_docdb\_subnet\_group\_enabled) | Controls if DocumentDB Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_docdb_subnet_group_name"></a> [docdb\_subnet\_group\_name](#input\_docdb\_subnet\_group\_name) | Desired name for the DocumentDB Subnet Group. | `string` | `""` | no |
-| <a name="input_map_customer_owned_ip_on_launch"></a> [map\_customer\_owned\_ip\_on\_launch](#input\_map\_customer\_owned\_ip\_on\_launch) | Should be true if network interfaces created in the subnet should be assigned a customer owned IP address. | `bool` | `false` | no |
-| <a name="input_map_public_ip_on_launch"></a> [map\_public\_ip\_on\_launch](#input\_map\_public\_ip\_on\_launch) | Should be false if you do not want to auto-assign public IP on launch. | `bool` | `false` | no |
-| <a name="input_memorydb_subnet_group_enabled"></a> [memorydb\_subnet\_group\_enabled](#input\_memorydb\_subnet\_group\_enabled) | Controls if MemoryDB Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_memorydb_subnet_group_name"></a> [memorydb\_subnet\_group\_name](#input\_memorydb\_subnet\_group\_name) | Desired name for the MemoryDB Subnet Group. | `string` | `""` | no |
-| <a name="input_module_tags_enabled"></a> [module\_tags\_enabled](#input\_module\_tags\_enabled) | Whether to create AWS Resource Tags for the module informations. | `bool` | `true` | no |
-| <a name="input_neptune_subnet_group_enabled"></a> [neptune\_subnet\_group\_enabled](#input\_neptune\_subnet\_group\_enabled) | Controls if Neptune Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_neptune_subnet_group_name"></a> [neptune\_subnet\_group\_name](#input\_neptune\_subnet\_group\_name) | Desired name for the Neptune Subnet Group. | `string` | `""` | no |
-| <a name="input_outpost_arn"></a> [outpost\_arn](#input\_outpost\_arn) | The ARN of the Outpost. | `string` | `""` | no |
-| <a name="input_redshift_subnet_group_enabled"></a> [redshift\_subnet\_group\_enabled](#input\_redshift\_subnet\_group\_enabled) | Controls if Redshift Subnet Group should be created. | `bool` | `false` | no |
-| <a name="input_redshift_subnet_group_name"></a> [redshift\_subnet\_group\_name](#input\_redshift\_subnet\_group\_name) | Desired name for the Redshift Subnet Group. | `string` | `""` | no |
-| <a name="input_resource_group_description"></a> [resource\_group\_description](#input\_resource\_group\_description) | The description of Resource Group. | `string` | `"Managed by Terraform."` | no |
-| <a name="input_resource_group_enabled"></a> [resource\_group\_enabled](#input\_resource\_group\_enabled) | Whether to create Resource Group to find and group AWS resources which are created by this module. | `bool` | `true` | no |
-| <a name="input_resource_group_name"></a> [resource\_group\_name](#input\_resource\_group\_name) | The name of Resource Group. A Resource Group name can have a maximum of 127 characters, including letters, numbers, hyphens, dots, and underscores. The name cannot start with `AWS` or `aws`. | `string` | `""` | no |
-| <a name="input_tags"></a> [tags](#input\_tags) | A map of tags to add to all resources. | `map(string)` | `{}` | no |
+| <a name="input_name"></a> [name](#input\_name) | (Required) The name of the subnet group. | `string` | n/a | yes |
+| <a name="input_subnets"></a> [subnets](#input\_subnets) | (Required) A configuration of subnets to create in the subnet group. Each block of `subnets` as defined below.<br>    (Required) `type` - The type of subnet. Valid values are `DUALSTACK` and `IPV6`.<br>    (Optional) `availability_zone` - The availability zone of the subnet. If the value of `availability_zone` and `availability_zone_id` are both not provided, the subnet will be created in random availability zone.<br>    (Optional) `availability_zone_id` - The availability zone ID of the subnet. If the value of `availability_zone` and `availability_zone_id` are both not provided, the subnet will be created in random availability zone. | <pre>map(object({<br>    type = optional(string, "DUALSTACK")<br><br>    availability_zone    = optional(string)<br>    availability_zone_id = optional(string)<br><br>    ipv4_cidr = optional(string)<br>    ipv6_cidr = optional(string)<br>  }))</pre> | n/a | yes |
+| <a name="input_vpc_id"></a> [vpc\_id](#input\_vpc\_id) | (Required) The ID of the VPC which the subnet group belongs to. | `string` | n/a | yes |
+| <a name="input_customer_owned_ipv4_address_assignment"></a> [customer\_owned\_ipv4\_address\_assignment](#input\_customer\_owned\_ipv4\_address\_assignment) | (Optional) A configuration for Customer-owned IPv4 address assignment. `customer_owned_ipv4_address_assignment` as defined below.<br>    (Optional) `enabled` - Whether to automatically request a Customer-owned IPv4 address for a new network interface in this subnet. Defaults to `false`.<br>    (Optional) `outpost` - The Amazon Resource Name (ARN) of the Outpost.<br>    (Optional) `pool` - The customer owned IPv4 address pool. | <pre>object({<br>    enabled = optional(bool, false)<br>    outpost = optional(string)<br>    pool    = optional(string)<br>  })</pre> | `{}` | no |
+| <a name="input_dax_subnet_group"></a> [dax\_subnet\_group](#input\_dax\_subnet\_group) | (Optional) A configuration of DAX Subnet Group. `dax_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create DAX Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the DAX Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the DAX Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_dms_replication_subnet_group"></a> [dms\_replication\_subnet\_group](#input\_dms\_replication\_subnet\_group) | (Optional) A configuration of DMS Replication Subnet Group. `dms_replication_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create DMS Replication Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the DMS Replication Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the DMS Replication Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_dns_config"></a> [dns\_config](#input\_dns\_config) | (Optional) A configuration for DNS queries for the subnet. `dns_config` as defined below.<br>    (Optional) `hostname_type` - The type of hostnames to assign to instances in the subnet at launch. For IPv6-only subnets, an instance DNS name must be based on the instance ID (`RESOURCE_NAME`). For dual-stack and IPv4-only subnets, you can specify whether DNS names use the instance IPv4 address (`IP_NAME`) or the instance ID (`RESOURCE_NAME`). Valid values are `IP_NAME`, `RESOURCE_NAME`. Defaults to `RESOURCE_NAME`.<br>    (Optional) `dns_resource_name_ipv4_enabled` - Whether to respond to DNS queries for instance hostnames with DNS A records. Always `false` for IPv6 only subnet. Defaults to `false`.<br>    (Optional) `dns_resource_name_ipv6_enabled` - Whether to respond to DNS queries for instance hostnames with DNS AAAA records. Always `true` for IPv6 only subnet. Defaults to `false`.<br>    (Optional) `dns64_enabled` - Whether to enable DNS64 to allow IPv6-only services in Amazon VPC to communicate with IPv4-only services and networks. Defaults to `false`. | <pre>object({<br>    hostname_type                  = optional(string, "RESOURCE_NAME")<br>    dns_resource_name_ipv4_enabled = optional(bool, false)<br>    dns_resource_name_ipv6_enabled = optional(bool, false)<br>    dns64_enabled                  = optional(bool, false)<br>  })</pre> | `{}` | no |
+| <a name="input_docdb_subnet_group"></a> [docdb\_subnet\_group](#input\_docdb\_subnet\_group) | (Optional) A configuration of DocumentDB Subnet Group. `docdb_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create DocumentDB Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the DocumentDB Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the DocumentDB Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_elasticache_subnet_group"></a> [elasticache\_subnet\_group](#input\_elasticache\_subnet\_group) | (Optional) A configuration of ElastiCache Subnet Group. `elasticache_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create ElastiCache Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the ElastiCache Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the ElastiCache Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_ipv6_address_assignment"></a> [ipv6\_address\_assignment](#input\_ipv6\_address\_assignment) | (Optional) A configuration for IPv6 address assignment. `ipv6_address_assignment` as defined below.<br>    (Optional) `enabled` - Whether to automatically request a IPv6 address for a new network interface in this subnet. Defaults to `false`. | <pre>object({<br>    enabled = optional(bool, false)<br>  })</pre> | `{}` | no |
+| <a name="input_local_network_interface_device_index"></a> [local\_network\_interface\_device\_index](#input\_local\_network\_interface\_device\_index) | (Optional) The device position for local network interfaces in this subnet. For example, `1` indicates local network interfaces in this subnet are the secondary network interface (eth1). A local network interface cannot be the primary network interface (eth0). | `number` | `null` | no |
+| <a name="input_memorydb_subnet_group"></a> [memorydb\_subnet\_group](#input\_memorydb\_subnet\_group) | (Optional) A configuration of MemoryDB Subnet Group. `memorydb_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create MemoryDB Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the MemoryDB Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the MemoryDB Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_module_tags_enabled"></a> [module\_tags\_enabled](#input\_module\_tags\_enabled) | (Optional) Whether to create AWS Resource Tags for the module informations. | `bool` | `true` | no |
+| <a name="input_neptune_subnet_group"></a> [neptune\_subnet\_group](#input\_neptune\_subnet\_group) | (Optional) A configuration of Neptune Subnet Group. `neptune_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create Neptune Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the Neptune Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the Neptune Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_public_ipv4_address_assignment"></a> [public\_ipv4\_address\_assignment](#input\_public\_ipv4\_address\_assignment) | (Optional) A configuration for public IPv4 address assignment. `public_ipv4_address_assignment` as defined below.<br>    (Optional) `enabled` - Whether to automatically request a public IPv4 address for a new network interface in this subnet. Defaults to `false`. | <pre>object({<br>    enabled = optional(bool, false)<br>  })</pre> | `{}` | no |
+| <a name="input_rds_subnet_group"></a> [rds\_subnet\_group](#input\_rds\_subnet\_group) | (Optional) A configuration of RDS Subnet Group. `rds_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create RDS Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the RDS Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the RDS Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_redshift_subnet_group"></a> [redshift\_subnet\_group](#input\_redshift\_subnet\_group) | (Optional) A configuration of Redshift Subnet Group. `redshift_subnet_group` as defined below.<br>    (Optional) `enabled` - Whether to create Redshift Subnet Group. Defaults to `false`.<br>    (Optional) `name` - The name of the Redshift Subnet Group. If not provided, the value of `name` will be used.<br>    (Optional) `description` - The description of the Redshift Subnet Group. | <pre>object({<br>    enabled     = optional(bool, false)<br>    name        = optional(string)<br>    description = optional(string, "Managed by Terraform.")<br>  })</pre> | `{}` | no |
+| <a name="input_resource_group_description"></a> [resource\_group\_description](#input\_resource\_group\_description) | (Optional) The description of Resource Group. | `string` | `"Managed by Terraform."` | no |
+| <a name="input_resource_group_enabled"></a> [resource\_group\_enabled](#input\_resource\_group\_enabled) | (Optional) Whether to create Resource Group to find and group AWS resources which are created by this module. | `bool` | `true` | no |
+| <a name="input_resource_group_name"></a> [resource\_group\_name](#input\_resource\_group\_name) | (Optional) The name of Resource Group. A Resource Group name can have a maximum of 127 characters, including letters, numbers, hyphens, dots, and underscores. The name cannot start with `AWS` or `aws`. | `string` | `""` | no |
+| <a name="input_tags"></a> [tags](#input\_tags) | (Optional) A map of tags to add to all resources. | `map(string)` | `{}` | no |
+| <a name="input_timeouts"></a> [timeouts](#input\_timeouts) | (Optional) How long to wait for the subnet group to be created/deleted. | <pre>object({<br>    create = optional(string, "10m")<br>    delete = optional(string, "20m")<br>  })</pre> | `{}` | no |
 
 ## Outputs
 
@@ -86,23 +81,24 @@ This module creates following resources.
 | <a name="output_arns"></a> [arns](#output\_arns) | A list of ARNs of subnets |
 | <a name="output_availability_zone_ids"></a> [availability\_zone\_ids](#output\_availability\_zone\_ids) | A list of availability zone IDs which the subnet group uses. |
 | <a name="output_availability_zones"></a> [availability\_zones](#output\_availability\_zones) | A list of availability zones which the subnet group uses. |
-| <a name="output_cache_subnet_group_id"></a> [cache\_subnet\_group\_id](#output\_cache\_subnet\_group\_id) | The ID of the Elasticache Subnet Group. |
-| <a name="output_cidr_blocks"></a> [cidr\_blocks](#output\_cidr\_blocks) | The CIDR blocks of the subnet group. |
-| <a name="output_dax_subnet_group_id"></a> [dax\_subnet\_group\_id](#output\_dax\_subnet\_group\_id) | The ID of the DAX Subnet Group. |
-| <a name="output_db_subnet_group_arn"></a> [db\_subnet\_group\_arn](#output\_db\_subnet\_group\_arn) | The ARN of the RDS Subnet Group. |
-| <a name="output_db_subnet_group_id"></a> [db\_subnet\_group\_id](#output\_db\_subnet\_group\_id) | The ID of the RDS Subnet Group. |
-| <a name="output_dms_replication_subnet_group_id"></a> [dms\_replication\_subnet\_group\_id](#output\_dms\_replication\_subnet\_group\_id) | The ID of the DMS Replication Subnet Group. |
-| <a name="output_docdb_subnet_group_arn"></a> [docdb\_subnet\_group\_arn](#output\_docdb\_subnet\_group\_arn) | The ARN of the DocumentDB Subnet Group. |
-| <a name="output_docdb_subnet_group_id"></a> [docdb\_subnet\_group\_id](#output\_docdb\_subnet\_group\_id) | The ID of the DocumentDB Subnet Group. |
+| <a name="output_customer_owned_ipv4_address_assignment"></a> [customer\_owned\_ipv4\_address\_assignment](#output\_customer\_owned\_ipv4\_address\_assignment) | The configuration of Customer-owned IPv4 address assignment.<br>    `enabled` - Whether to automatically assign Customer-owned IPv4 address to instances launched in the subnet group.<br>    `outpost` - The ARN of the Outpost.<br>    `pool` - The ID of the Customer-owned IPv4 address pool. |
+| <a name="output_dax_subnet_group"></a> [dax\_subnet\_group](#output\_dax\_subnet\_group) | The configuration of DAX Subnet Group.<br>    `id` - The ID of the DAX Subnet Group.<br>    `name` - The name of the DAX Subnet Group.<br>    `description` - The description of the DAX Subnet Group. |
+| <a name="output_dms_replication_subnet_group"></a> [dms\_replication\_subnet\_group](#output\_dms\_replication\_subnet\_group) | The configuration of DMS Replication Subnet Group.<br>    `id` - The ID of the DMS Replication Subnet Group.<br>    `arn` - The ARN of the DMS Replication Subnet Group.<br>    `name` - The name of the DMS Replication Subnet Group.<br>    `description` - The description of the DMS Replication Subnet Group. |
+| <a name="output_dns_config"></a> [dns\_config](#output\_dns\_config) | The DNS configuration for the subnet group.<br>    `id` - The ID of the DAX Subnet Group. |
+| <a name="output_docdb_subnet_group"></a> [docdb\_subnet\_group](#output\_docdb\_subnet\_group) | The configuration of DocumentDB Subnet Group.<br>    `id` - The ID of the DocumentDB Subnet Group.<br>    `arn` - The ARN of the DocumentDB Subnet Group.<br>    `name` - The name of the DocumentDB Subnet Group.<br>    `description` - The description of the DocumentDB Subnet Group. |
+| <a name="output_elasticache_subnet_group"></a> [elasticache\_subnet\_group](#output\_elasticache\_subnet\_group) | The configuration of ElastiCache Subnet Group.<br>    `id` - The ID of the ElastiCache Subnet Group.<br>    `arn` - The ARN of the ElastiCache Subnet Group.<br>    `name` - The name of the ElastiCache Subnet Group.<br>    `description` - The description of the ElastiCache Subnet Group. |
 | <a name="output_ids"></a> [ids](#output\_ids) | A list of IDs of subnets |
-| <a name="output_ipv6_cidr_blocks"></a> [ipv6\_cidr\_blocks](#output\_ipv6\_cidr\_blocks) | The IPv6 CIDR blocks of the subnet group. |
-| <a name="output_memorydb_subnet_group_arn"></a> [memorydb\_subnet\_group\_arn](#output\_memorydb\_subnet\_group\_arn) | The ARN of the MemoryDB Subnet Group. |
-| <a name="output_memorydb_subnet_group_id"></a> [memorydb\_subnet\_group\_id](#output\_memorydb\_subnet\_group\_id) | The ID of the MemoryDB Subnet Group. |
+| <a name="output_ipv4_cidrs"></a> [ipv4\_cidrs](#output\_ipv4\_cidrs) | The IPv4 CIDR blocks of the subnet group. |
+| <a name="output_ipv6_address_assignment"></a> [ipv6\_address\_assignment](#output\_ipv6\_address\_assignment) | The configuration of IPv6 address assignment.<br>    `enabled` - Whether to automatically assign IPv6 address to instances launched in the subnet group. |
+| <a name="output_ipv6_cidrs"></a> [ipv6\_cidrs](#output\_ipv6\_cidrs) | The IPv6 CIDR blocks of the subnet group. |
+| <a name="output_local_network_interface_device_index"></a> [local\_network\_interface\_device\_index](#output\_local\_network\_interface\_device\_index) | The device position for local network interfaces in this subnet. |
+| <a name="output_memorydb_subnet_group"></a> [memorydb\_subnet\_group](#output\_memorydb\_subnet\_group) | The configuration of MemoryDB Subnet Group.<br>    `id` - The ID of the MemoryDB Subnet Group.<br>    `arn` - The ARN of the MemoryDB Subnet Group.<br>    `name` - The name of the MemoryDB Subnet Group.<br>    `description` - The description of the MemoryDB Subnet Group. |
 | <a name="output_name"></a> [name](#output\_name) | The name of the subnet group. |
-| <a name="output_neptune_subnet_group_arn"></a> [neptune\_subnet\_group\_arn](#output\_neptune\_subnet\_group\_arn) | The ARN of the Neptune Subnet Group. |
-| <a name="output_neptune_subnet_group_id"></a> [neptune\_subnet\_group\_id](#output\_neptune\_subnet\_group\_id) | The ID of the Neptune DB Subnet Group. |
-| <a name="output_redshift_subnet_group_arn"></a> [redshift\_subnet\_group\_arn](#output\_redshift\_subnet\_group\_arn) | The ARN of the Redshift Subnet Group. |
-| <a name="output_redshift_subnet_group_id"></a> [redshift\_subnet\_group\_id](#output\_redshift\_subnet\_group\_id) | The ID of the Redshift Subnet Group. |
+| <a name="output_neptune_subnet_group"></a> [neptune\_subnet\_group](#output\_neptune\_subnet\_group) | The configuration of Neptune Subnet Group.<br>    `id` - The ID of the Neptune Subnet Group.<br>    `arn` - The ARN of the Neptune Subnet Group.<br>    `name` - The name of the Neptune Subnet Group.<br>    `description` - The description of the Neptune Subnet Group. |
+| <a name="output_owner"></a> [owner](#output\_owner) | The ID of the AWS account that owns subnets in the subnet group. |
+| <a name="output_public_ipv4_address_assignment"></a> [public\_ipv4\_address\_assignment](#output\_public\_ipv4\_address\_assignment) | The configuration of public IPv4 address assignment.<br>    `enabled` - Whether to automatically assign public IPv4 address to instances launched in the subnet group. |
+| <a name="output_rds_subnet_group"></a> [rds\_subnet\_group](#output\_rds\_subnet\_group) | The configuration of RDS Subnet Group.<br>    `id` - The ID of the RDS Subnet Group.<br>    `arn` - The ARN of the RDS Subnet Group.<br>    `name` - The name of the RDS Subnet Group.<br>    `description` - The description of the RDS Subnet Group. |
+| <a name="output_redshift_subnet_group"></a> [redshift\_subnet\_group](#output\_redshift\_subnet\_group) | The configuration of Redshift Subnet Group.<br>    `id` - The ID of the Redshift Subnet Group.<br>    `arn` - The ARN of the Redshift Subnet Group.<br>    `name` - The name of the Redshift Subnet Group.<br>    `description` - The description of the Redshift Subnet Group. |
 | <a name="output_subnets"></a> [subnets](#output\_subnets) | A list of subnets of the subnet group. |
 | <a name="output_subnets_by_az"></a> [subnets\_by\_az](#output\_subnets\_by\_az) | A map of subnets of the subnet group which are grouped by availability zone id. |
 | <a name="output_vpc_id"></a> [vpc\_id](#output\_vpc\_id) | The ID of the VPC which the subnet group belongs to. |
diff --git a/modules/subnet-group/integrations.tf b/modules/subnet-group/integrations.tf
new file mode 100644
index 0000000..f1eae91
--- /dev/null
+++ b/modules/subnet-group/integrations.tf
@@ -0,0 +1,169 @@
+###################################################
+# Subnet Group for DAX
+###################################################
+
+resource "aws_dax_subnet_group" "this" {
+  count = var.dax_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.dax_subnet_group.name, var.name)
+  description = var.dax_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  # INFO: Not support resource tags
+  # tags = {}
+}
+
+
+###################################################
+# Subnet Group for DMS Replication
+###################################################
+
+resource "aws_dms_replication_subnet_group" "this" {
+  count = var.dms_replication_subnet_group.enabled ? 1 : 0
+
+  replication_subnet_group_id          = coalesce(var.dms_replication_subnet_group.name, var.name)
+  replication_subnet_group_description = var.dms_replication_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.dms_replication_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
+
+
+###################################################
+# Subnet Group for DocumentDB
+###################################################
+
+resource "aws_docdb_subnet_group" "this" {
+  count = var.docdb_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.docdb_subnet_group.name, var.name)
+  description = var.docdb_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.docdb_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
+
+
+###################################################
+# Subnet Group for ElastiCache
+###################################################
+
+resource "aws_elasticache_subnet_group" "this" {
+  count = var.elasticache_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.elasticache_subnet_group.name, var.name)
+  description = var.elasticache_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.elasticache_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
+
+
+###################################################
+# Subnet Group for MemoryDB
+###################################################
+
+resource "aws_memorydb_subnet_group" "this" {
+  count = var.memorydb_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.memorydb_subnet_group.name, var.name)
+  description = var.memorydb_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.memorydb_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
+
+
+###################################################
+# Subnet Group for Neptune
+###################################################
+
+resource "aws_neptune_subnet_group" "this" {
+  count = var.neptune_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.neptune_subnet_group.name, var.name)
+  description = var.neptune_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.neptune_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
+
+
+###################################################
+# Subnet Group for RDS
+###################################################
+
+resource "aws_db_subnet_group" "this" {
+  count = var.rds_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.rds_subnet_group.name, var.name)
+  description = var.rds_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.rds_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
+
+
+###################################################
+# Subnet Group for Redshift
+###################################################
+
+resource "aws_redshift_subnet_group" "this" {
+  count = var.redshift_subnet_group.enabled ? 1 : 0
+
+  name        = coalesce(var.redshift_subnet_group.name, var.name)
+  description = var.redshift_subnet_group.description
+
+  subnet_ids = values(aws_subnet.this)[*].id
+
+  tags = merge(
+    {
+      "Name" = coalesce(var.redshift_subnet_group.name, var.name)
+    },
+    local.module_tags,
+    var.tags,
+  )
+}
diff --git a/modules/subnet-group/main.tf b/modules/subnet-group/main.tf
index 4d51a2a..4506fce 100644
--- a/modules/subnet-group/main.tf
+++ b/modules/subnet-group/main.tf
@@ -14,6 +14,25 @@ locals {
   } : {}
 }
 
+data "aws_availability_zones" "available" {
+  state = "available"
+}
+
+locals {
+  available_availablity_zones    = data.aws_availability_zones.available.names
+  available_availablity_zone_ids = data.aws_availability_zones.available.zone_ids
+
+  az = {
+    for idx, id in local.available_availablity_zone_ids :
+    id => local.available_availablity_zones[idx]
+  }
+
+  hostname_types = {
+    "RESOURCE_NAME" = "resource-name"
+    "IP_NAME"       = "ip-name"
+  }
+}
+
 locals {
   availability_zones = distinct(
     values(aws_subnet.this)[*].availability_zone
@@ -21,9 +40,6 @@ locals {
   availability_zone_ids = distinct(
     values(aws_subnet.this)[*].availability_zone_id
   )
-}
-
-locals {
   subnets = [
     for subnet in aws_subnet.this : {
       id   = subnet.id
@@ -39,149 +55,85 @@ locals {
   ]
 }
 
-resource "aws_subnet" "this" {
-  for_each = var.subnets
-
-  vpc_id               = var.vpc_id
-  availability_zone    = lookup(each.value, "availability_zone", null)
-  availability_zone_id = lookup(each.value, "availability_zone_id", null)
-
-  cidr_block      = lookup(each.value, "cidr_block", "")
-  ipv6_cidr_block = lookup(each.value, "ipv6_cidr_block", null)
-
-  map_public_ip_on_launch         = var.map_public_ip_on_launch
-  assign_ipv6_address_on_creation = var.assign_ipv6_address_on_creation
-
-  outpost_arn                     = var.outpost_arn
-  customer_owned_ipv4_pool        = var.customer_owned_ipv4_pool
-  map_customer_owned_ip_on_launch = var.map_customer_owned_ip_on_launch
-
-  tags = merge(
-    {
-      "Name" = each.key
-    },
-    local.module_tags,
-    var.tags,
-  )
-}
-
 
 ###################################################
-# Subnet Groups for Managed Data Services
+# Subnets of the Subnet Group
 ###################################################
 
-resource "aws_db_subnet_group" "this" {
-  count = var.db_subnet_group_enabled ? 1 : 0
-
-  name       = var.db_subnet_group_name
-  subnet_ids = values(aws_subnet.this)[*].id
+# INFO: Not supported attributes
+# - `availability_zone_id`
+resource "aws_subnet" "this" {
+  for_each = var.subnets
 
-  tags = merge(
-    {
-      "Name" = var.db_subnet_group_name
-    },
-    local.module_tags,
-    var.tags,
+  vpc_id = var.vpc_id
+  availability_zone = (each.value.availability_zone != null
+    ? each.value.availability_zone
+    : (each.value.availability_zone_id != null
+      ? local.az[each.value.availability_zone_id]
+      : null
+    )
   )
-}
 
-resource "aws_elasticache_subnet_group" "this" {
-  count = var.cache_subnet_group_enabled ? 1 : 0
+  enable_lni_at_device_index = var.local_network_interface_device_index
 
-  name       = var.cache_subnet_group_name
-  subnet_ids = values(aws_subnet.this)[*].id
 
-  tags = merge(
-    {
-      "Name" = var.cache_subnet_group_name
-    },
-    local.module_tags,
-    var.tags,
-  )
-}
+  ## IP CIDR Blocks
+  ipv6_native = each.value.type == "IPV6"
 
-resource "aws_redshift_subnet_group" "this" {
-  count = var.redshift_subnet_group_enabled ? 1 : 0
+  cidr_block      = each.value.ipv4_cidr
+  ipv6_cidr_block = each.value.ipv6_cidr
 
-  name       = var.redshift_subnet_group_name
-  subnet_ids = values(aws_subnet.this)[*].id
 
-  tags = merge(
-    {
-      "Name" = var.redshift_subnet_group_name
-    },
-    local.module_tags,
-    var.tags,
+  ## IP Assignments
+  map_public_ip_on_launch = (each.value.type == "IPV6"
+    ? false
+    : var.public_ipv4_address_assignment.enabled
   )
-}
-
-resource "aws_neptune_subnet_group" "this" {
-  count = var.neptune_subnet_group_enabled ? 1 : 0
-
-  name       = var.neptune_subnet_group_name
-  subnet_ids = values(aws_subnet.this)[*].id
-
-  tags = merge(
-    {
-      "Name" = var.neptune_subnet_group_name
-    },
-    local.module_tags,
-    var.tags,
+  assign_ipv6_address_on_creation = (each.value.type == "IPV6"
+    ? true
+    : var.ipv6_address_assignment.enabled
   )
-}
-
-resource "aws_docdb_subnet_group" "this" {
-  count = var.docdb_subnet_group_enabled ? 1 : 0
-
-  name       = var.docdb_subnet_group_name
-  subnet_ids = values(aws_subnet.this)[*].id
-
-  tags = merge(
-    {
-      "Name" = var.docdb_subnet_group_name
-    },
-    local.module_tags,
-    var.tags,
+  map_customer_owned_ip_on_launch = (each.value.type == "IPV6"
+    ? null
+    : (var.customer_owned_ipv4_address_assignment.enabled
+      ? true
+      : null
+    )
+  )
+  outpost_arn = (var.customer_owned_ipv4_address_assignment.enabled
+    ? var.customer_owned_ipv4_address_assignment.outpost
+    : null
+  )
+  customer_owned_ipv4_pool = (var.customer_owned_ipv4_address_assignment.enabled
+    ? var.customer_owned_ipv4_address_assignment.pool
+    : null
   )
-}
-
-resource "aws_dax_subnet_group" "this" {
-  count = var.dax_subnet_group_enabled ? 1 : 0
-
-  name       = var.dax_subnet_group_name
-  subnet_ids = values(aws_subnet.this)[*].id
-
-  # INFO: Not support resource tags
-  # tags = {}
-}
-
-resource "aws_dms_replication_subnet_group" "this" {
-  count = var.dms_replication_subnet_group_enabled ? 1 : 0
-
-  replication_subnet_group_id          = var.dms_replication_subnet_group_name
-  replication_subnet_group_description = "Managed by Terraform."
 
-  subnet_ids = values(aws_subnet.this)[*].id
 
-  tags = merge(
-    {
-      "Name" = var.dms_replication_subnet_group_name
-    },
-    local.module_tags,
-    var.tags,
+  ## DNS Configurations
+  private_dns_hostname_type_on_launch = (each.value.type == "IPV6"
+    ? "resource-name"
+    : local.hostname_types[var.dns_config.hostname_type]
   )
-}
+  enable_resource_name_dns_a_record_on_launch = (each.value.type == "IPV6"
+    ? false
+    : var.dns_config.dns_resource_name_ipv4_enabled
+  )
+  enable_resource_name_dns_aaaa_record_on_launch = (each.value.type == "IPV6"
+    ? true
+    : var.dns_config.dns_resource_name_ipv6_enabled
+  )
+  enable_dns64 = var.dns_config.dns64_enabled
 
-resource "aws_memorydb_subnet_group" "this" {
-  count = var.memorydb_subnet_group_enabled ? 1 : 0
 
-  name        = var.memorydb_subnet_group_name
-  description = "Managed by Terraform."
-  subnet_ids  = values(aws_subnet.this)[*].id
+  timeouts {
+    create = var.timeouts.create
+    delete = var.timeouts.delete
+  }
 
   tags = merge(
     {
-      "Name" = var.memorydb_subnet_group_name
+      "Name" = each.key
     },
     local.module_tags,
     var.tags,
diff --git a/modules/subnet-group/outputs.tf b/modules/subnet-group/outputs.tf
index 381c981..a9d00d0 100644
--- a/modules/subnet-group/outputs.tf
+++ b/modules/subnet-group/outputs.tf
@@ -5,7 +5,7 @@ output "name" {
 
 output "vpc_id" {
   description = "The ID of the VPC which the subnet group belongs to."
-  value       = var.vpc_id
+  value       = values(aws_subnet.this)[0].vpc_id
 }
 
 output "ids" {
@@ -18,12 +18,17 @@ output "arns" {
   value       = values(aws_subnet.this)[*].arn
 }
 
-output "cidr_blocks" {
-  description = "The CIDR blocks of the subnet group."
-  value       = values(aws_subnet.this)[*].cidr_block
+output "owner" {
+  description = "The ID of the AWS account that owns subnets in the subnet group."
+  value       = values(aws_subnet.this)[0].owner_id
 }
 
-output "ipv6_cidr_blocks" {
+output "ipv4_cidrs" {
+  description = "The IPv4 CIDR blocks of the subnet group."
+  value       = compact(values(aws_subnet.this)[*].cidr_block)
+}
+
+output "ipv6_cidrs" {
   description = "The IPv6 CIDR blocks of the subnet group."
   value       = compact(values(aws_subnet.this)[*].ipv6_cidr_block)
 }
@@ -51,85 +56,209 @@ output "subnets_by_az" {
   }
 }
 
-output "db_subnet_group_id" {
-  description = "The ID of the RDS Subnet Group."
-  value       = one(aws_db_subnet_group.this[*].id)
+output "local_network_interface_device_index" {
+  description = "The device position for local network interfaces in this subnet."
+  value       = var.local_network_interface_device_index
 }
 
-output "db_subnet_group_arn" {
-  description = "The ARN of the RDS Subnet Group."
-  value       = one(aws_db_subnet_group.this[*].arn)
+output "public_ipv4_address_assignment" {
+  description = <<EOF
+  The configuration of public IPv4 address assignment.
+    `enabled` - Whether to automatically assign public IPv4 address to instances launched in the subnet group.
+  EOF
+  value = {
+    enabled = values(aws_subnet.this)[0].map_public_ip_on_launch
+  }
 }
 
-output "cache_subnet_group_id" {
-  description = "The ID of the Elasticache Subnet Group."
-  value       = one(aws_elasticache_subnet_group.this[*].id)
+output "customer_owned_ipv4_address_assignment" {
+  description = <<EOF
+  The configuration of Customer-owned IPv4 address assignment.
+    `enabled` - Whether to automatically assign Customer-owned IPv4 address to instances launched in the subnet group.
+    `outpost` - The ARN of the Outpost.
+    `pool` - The ID of the Customer-owned IPv4 address pool.
+  EOF
+  value = {
+    enabled = values(aws_subnet.this)[0].map_public_ip_on_launch
+    outpost = values(aws_subnet.this)[0].outpost_arn
+    pool    = values(aws_subnet.this)[0].customer_owned_ipv4_pool
+  }
 }
 
-# INFO: Not support arn output
-# output "cache_subnet_group_arn" {
-#   description = "The ARN of the Elasticache Subnet Group."
-#   value       = one(aws_elasticache_subnet_group.this[*].arn)
-# }
-
-output "redshift_subnet_group_id" {
-  description = "The ID of the Redshift Subnet Group."
-  value       = one(aws_redshift_subnet_group.this[*].id)
+output "ipv6_address_assignment" {
+  description = <<EOF
+  The configuration of IPv6 address assignment.
+    `enabled` - Whether to automatically assign IPv6 address to instances launched in the subnet group.
+  EOF
+  value = {
+    enabled = values(aws_subnet.this)[0].assign_ipv6_address_on_creation
+  }
 }
 
-output "redshift_subnet_group_arn" {
-  description = "The ARN of the Redshift Subnet Group."
-  value       = one(aws_redshift_subnet_group.this[*].arn)
+output "dns_config" {
+  description = <<EOF
+  The DNS configuration for the subnet group.
+    `id` - The ID of the DAX Subnet Group.
+  EOF
+  value = {
+    hostname_type = {
+      for k, v in local.hostname_types :
+      v => k
+    }[values(aws_subnet.this)[0].private_dns_hostname_type_on_launch]
+    dns_resource_name_ipv4_enabled = values(aws_subnet.this)[0].enable_resource_name_dns_a_record_on_launch
+    dns_resource_name_ipv6_enabled = values(aws_subnet.this)[0].enable_resource_name_dns_aaaa_record_on_launch
+    dns64_enabled                  = values(aws_subnet.this)[0].enable_dns64
+  }
 }
 
-output "neptune_subnet_group_id" {
-  description = "The ID of the Neptune DB Subnet Group."
-  value       = one(aws_neptune_subnet_group.this[*].id)
+output "dax_subnet_group" {
+  description = <<EOF
+  The configuration of DAX Subnet Group.
+    `id` - The ID of the DAX Subnet Group.
+    `name` - The name of the DAX Subnet Group.
+    `description` - The description of the DAX Subnet Group.
+  EOF
+  value = (var.dax_subnet_group.enabled
+    ? {
+      id = one(aws_dax_subnet_group.this[*].id)
+      # INFO: Not support arn output
+      # arn         = one(aws_dax_subnet_group.this[*])
+      name        = one(aws_dax_subnet_group.this[*].name)
+      description = one(aws_dax_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
 
-output "neptune_subnet_group_arn" {
-  description = "The ARN of the Neptune Subnet Group."
-  value       = one(aws_neptune_subnet_group.this[*].arn)
+output "dms_replication_subnet_group" {
+  description = <<EOF
+  The configuration of DMS Replication Subnet Group.
+    `id` - The ID of the DMS Replication Subnet Group.
+    `arn` - The ARN of the DMS Replication Subnet Group.
+    `name` - The name of the DMS Replication Subnet Group.
+    `description` - The description of the DMS Replication Subnet Group.
+  EOF
+  value = (var.dms_replication_subnet_group.enabled
+    ? {
+      id          = one(aws_dms_replication_subnet_group.this[*].id)
+      arn         = one(aws_dms_replication_subnet_group.this[*].replication_subnet_group_arn)
+      name        = one(aws_dms_replication_subnet_group.this[*].replication_subnet_group_id)
+      description = one(aws_dms_replication_subnet_group.this[*].replication_subnet_group_description)
+    }
+    : null
+  )
 }
 
-output "docdb_subnet_group_id" {
-  description = "The ID of the DocumentDB Subnet Group."
-  value       = one(aws_docdb_subnet_group.this[*].id)
+output "docdb_subnet_group" {
+  description = <<EOF
+  The configuration of DocumentDB Subnet Group.
+    `id` - The ID of the DocumentDB Subnet Group.
+    `arn` - The ARN of the DocumentDB Subnet Group.
+    `name` - The name of the DocumentDB Subnet Group.
+    `description` - The description of the DocumentDB Subnet Group.
+  EOF
+  value = (var.docdb_subnet_group.enabled
+    ? {
+      id          = one(aws_docdb_subnet_group.this[*].id)
+      arn         = one(aws_docdb_subnet_group.this[*].arn)
+      name        = one(aws_docdb_subnet_group.this[*].name)
+      description = one(aws_docdb_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
 
-output "docdb_subnet_group_arn" {
-  description = "The ARN of the DocumentDB Subnet Group."
-  value       = one(aws_docdb_subnet_group.this[*].arn)
+output "elasticache_subnet_group" {
+  description = <<EOF
+  The configuration of ElastiCache Subnet Group.
+    `id` - The ID of the ElastiCache Subnet Group.
+    `arn` - The ARN of the ElastiCache Subnet Group.
+    `name` - The name of the ElastiCache Subnet Group.
+    `description` - The description of the ElastiCache Subnet Group.
+  EOF
+  value = (var.elasticache_subnet_group.enabled
+    ? {
+      id          = one(aws_elasticache_subnet_group.this[*].id)
+      arn         = one(aws_elasticache_subnet_group.this[*].arn)
+      name        = one(aws_elasticache_subnet_group.this[*].name)
+      description = one(aws_elasticache_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
 
-output "dax_subnet_group_id" {
-  description = "The ID of the DAX Subnet Group."
-  value       = one(aws_dax_subnet_group.this[*].id)
+output "memorydb_subnet_group" {
+  description = <<EOF
+  The configuration of MemoryDB Subnet Group.
+    `id` - The ID of the MemoryDB Subnet Group.
+    `arn` - The ARN of the MemoryDB Subnet Group.
+    `name` - The name of the MemoryDB Subnet Group.
+    `description` - The description of the MemoryDB Subnet Group.
+  EOF
+  value = (var.memorydb_subnet_group.enabled
+    ? {
+      id          = one(aws_memorydb_subnet_group.this[*].id)
+      arn         = one(aws_memorydb_subnet_group.this[*].arn)
+      name        = one(aws_memorydb_subnet_group.this[*].name)
+      description = one(aws_memorydb_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
 
-# INFO: Not support arn output
-# output "dax_subnet_group_arn" {
-#   description = "The ARN of the DAX Subnet Group."
-#   value       = one(aws_dax_subnet_group.this[*].arn)
-# }
-
-output "dms_replication_subnet_group_id" {
-  description = "The ID of the DMS Replication Subnet Group."
-  value       = one(aws_dms_replication_subnet_group.this[*].id)
+output "neptune_subnet_group" {
+  description = <<EOF
+  The configuration of Neptune Subnet Group.
+    `id` - The ID of the Neptune Subnet Group.
+    `arn` - The ARN of the Neptune Subnet Group.
+    `name` - The name of the Neptune Subnet Group.
+    `description` - The description of the Neptune Subnet Group.
+  EOF
+  value = (var.neptune_subnet_group.enabled
+    ? {
+      id          = one(aws_neptune_subnet_group.this[*].id)
+      arn         = one(aws_neptune_subnet_group.this[*].arn)
+      name        = one(aws_neptune_subnet_group.this[*].name)
+      description = one(aws_neptune_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
 
-# INFO: Not support arn output
-# output "dms_replication_subnet_group_arn" {
-#   description = "The ARN of the DMS Replication Subnet Group."
-#   value       = one(aws_dms_replication_subnet_group.this[*].arn)
-# }
-
-output "memorydb_subnet_group_id" {
-  description = "The ID of the MemoryDB Subnet Group."
-  value       = one(aws_memorydb_subnet_group.this[*].id)
+output "rds_subnet_group" {
+  description = <<EOF
+  The configuration of RDS Subnet Group.
+    `id` - The ID of the RDS Subnet Group.
+    `arn` - The ARN of the RDS Subnet Group.
+    `name` - The name of the RDS Subnet Group.
+    `description` - The description of the RDS Subnet Group.
+  EOF
+  value = (var.rds_subnet_group.enabled
+    ? {
+      id          = one(aws_db_subnet_group.this[*].id)
+      arn         = one(aws_db_subnet_group.this[*].arn)
+      name        = one(aws_db_subnet_group.this[*].name)
+      description = one(aws_db_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
 
-output "memorydb_subnet_group_arn" {
-  description = "The ARN of the MemoryDB Subnet Group."
-  value       = one(aws_memorydb_subnet_group.this[*].arn)
+output "redshift_subnet_group" {
+  description = <<EOF
+  The configuration of Redshift Subnet Group.
+    `id` - The ID of the Redshift Subnet Group.
+    `arn` - The ARN of the Redshift Subnet Group.
+    `name` - The name of the Redshift Subnet Group.
+    `description` - The description of the Redshift Subnet Group.
+  EOF
+  value = (var.redshift_subnet_group.enabled
+    ? {
+      id          = one(aws_redshift_subnet_group.this[*].id)
+      arn         = one(aws_redshift_subnet_group.this[*].arn)
+      name        = one(aws_redshift_subnet_group.this[*].name)
+      description = one(aws_redshift_subnet_group.this[*].description)
+    }
+    : null
+  )
 }
diff --git a/modules/subnet-group/variables.tf b/modules/subnet-group/variables.tf
index b662911..0e80ef5 100644
--- a/modules/subnet-group/variables.tf
+++ b/modules/subnet-group/variables.tf
@@ -1,154 +1,284 @@
 variable "name" {
-  description = "The name of the subnet group."
+  description = "(Required) The name of the subnet group."
   type        = string
+  nullable    = false
 }
 
 variable "vpc_id" {
-  description = "The ID of the VPC which the subnet group belongs to."
+  description = "(Required) The ID of the VPC which the subnet group belongs to."
   type        = string
+  nullable    = false
 }
 
 variable "subnets" {
-  description = "A map of subnet parameters to create subnets for the subnet group."
-  type        = map(map(any))
-}
+  description = <<EOF
+  (Required) A configuration of subnets to create in the subnet group. Each block of `subnets` as defined below.
+    (Required) `type` - The type of subnet. Valid values are `DUALSTACK` and `IPV6`.
+    (Optional) `availability_zone` - The availability zone of the subnet. If the value of `availability_zone` and `availability_zone_id` are both not provided, the subnet will be created in random availability zone.
+    (Optional) `availability_zone_id` - The availability zone ID of the subnet. If the value of `availability_zone` and `availability_zone_id` are both not provided, the subnet will be created in random availability zone.
+  EOF
+  type = map(object({
+    type = optional(string, "DUALSTACK")
 
-variable "map_public_ip_on_launch" {
-  description = "Should be false if you do not want to auto-assign public IP on launch."
-  type        = bool
-  default     = false
-}
+    availability_zone    = optional(string)
+    availability_zone_id = optional(string)
 
-variable "assign_ipv6_address_on_creation" {
-  description = "Assign IPv6 address on subnet, must be disabled to change IPv6 CIDRs. This is the IPv6 equivalent of map_public_ip_on_launch."
-  type        = bool
-  default     = false
-}
+    ipv4_cidr = optional(string)
+    ipv6_cidr = optional(string)
+  }))
+  nullable = false
 
-variable "outpost_arn" {
-  description = "The ARN of the Outpost."
-  type        = string
-  default     = ""
+  validation {
+    condition     = length(keys(var.subnets)) > 0
+    error_message = "At least one subnet must be provided."
+  }
+  validation {
+    condition = alltrue([
+      for subnet in values(var.subnets) :
+      contains(["DUALSTACK", "IPV6"], subnet.type)
+    ])
+    error_message = "Valid values for `type` of each subnet are `DUALSTACK` and `IPV6`."
+  }
+  validation {
+    condition = alltrue([
+      for subnet in values(var.subnets) :
+      subnet.ipv4_cidr != null
+      if subnet.type == "DUALSTACK"
+    ])
+    error_message = "IPv4 CIDR block must be provided for `DUALSTACK` subnet."
+  }
+  validation {
+    condition = alltrue([
+      for subnet in values(var.subnets) :
+      subnet.ipv6_cidr != null && subnet.ipv4_cidr == null
+      if subnet.type == "IPV6"
+    ])
+    error_message = "IPv6 CIDR block must be provided for `IPV6` subnet."
+  }
 }
 
-variable "customer_owned_ipv4_pool" {
-  description = "The customer owned IPv4 address pool. `outpost_arn` argument must be specified when configured."
-  type        = string
-  default     = ""
+variable "local_network_interface_device_index" {
+  description = <<EOF
+  (Optional) The device position for local network interfaces in this subnet. For example, `1` indicates local network interfaces in this subnet are the secondary network interface (eth1). A local network interface cannot be the primary network interface (eth0).
+  EOF
+  type        = number
+  default     = null
+  nullable    = true
 }
 
-variable "map_customer_owned_ip_on_launch" {
-  description = "Should be true if network interfaces created in the subnet should be assigned a customer owned IP address."
-  type        = bool
-  default     = false
+variable "public_ipv4_address_assignment" {
+  description = <<EOF
+  (Optional) A configuration for public IPv4 address assignment. `public_ipv4_address_assignment` as defined below.
+    (Optional) `enabled` - Whether to automatically request a public IPv4 address for a new network interface in this subnet. Defaults to `false`.
+  EOF
+  type = object({
+    enabled = optional(bool, false)
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "db_subnet_group_enabled" {
-  description = "Controls if RDS Subnet Group should be created."
-  type        = bool
-  default     = false
+variable "customer_owned_ipv4_address_assignment" {
+  description = <<EOF
+  (Optional) A configuration for Customer-owned IPv4 address assignment. `customer_owned_ipv4_address_assignment` as defined below.
+    (Optional) `enabled` - Whether to automatically request a Customer-owned IPv4 address for a new network interface in this subnet. Defaults to `false`.
+    (Optional) `outpost` - The Amazon Resource Name (ARN) of the Outpost.
+    (Optional) `pool` - The customer owned IPv4 address pool.
+  EOF
+  type = object({
+    enabled = optional(bool, false)
+    outpost = optional(string)
+    pool    = optional(string)
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "db_subnet_group_name" {
-  description = "Desired name for the RDS Subnet Group."
-  type        = string
-  default     = ""
+variable "ipv6_address_assignment" {
+  description = <<EOF
+  (Optional) A configuration for IPv6 address assignment. `ipv6_address_assignment` as defined below.
+    (Optional) `enabled` - Whether to automatically request a IPv6 address for a new network interface in this subnet. Defaults to `false`.
+  EOF
+  type = object({
+    enabled = optional(bool, false)
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "cache_subnet_group_enabled" {
-  description = "Controls if Elasticache Subnet Group should be created."
-  type        = bool
-  default     = false
-}
+variable "dns_config" {
+  description = <<EOF
+  (Optional) A configuration for DNS queries for the subnet. `dns_config` as defined below.
+    (Optional) `hostname_type` - The type of hostnames to assign to instances in the subnet at launch. For IPv6-only subnets, an instance DNS name must be based on the instance ID (`RESOURCE_NAME`). For dual-stack and IPv4-only subnets, you can specify whether DNS names use the instance IPv4 address (`IP_NAME`) or the instance ID (`RESOURCE_NAME`). Valid values are `IP_NAME`, `RESOURCE_NAME`. Defaults to `RESOURCE_NAME`.
+    (Optional) `dns_resource_name_ipv4_enabled` - Whether to respond to DNS queries for instance hostnames with DNS A records. Always `false` for IPv6 only subnet. Defaults to `false`.
+    (Optional) `dns_resource_name_ipv6_enabled` - Whether to respond to DNS queries for instance hostnames with DNS AAAA records. Always `true` for IPv6 only subnet. Defaults to `false`.
+    (Optional) `dns64_enabled` - Whether to enable DNS64 to allow IPv6-only services in Amazon VPC to communicate with IPv4-only services and networks. Defaults to `false`.
+  EOF
+  type = object({
+    hostname_type                  = optional(string, "RESOURCE_NAME")
+    dns_resource_name_ipv4_enabled = optional(bool, false)
+    dns_resource_name_ipv6_enabled = optional(bool, false)
+    dns64_enabled                  = optional(bool, false)
+  })
+  default  = {}
+  nullable = false
 
-variable "cache_subnet_group_name" {
-  description = "Desired name for the Elasticache Subnet Group."
-  type        = string
-  default     = ""
+  validation {
+    condition     = contains(["IP_NAME", "RESOURCE_NAME"], var.dns_config.hostname_type)
+    error_message = "Valid values for `hostname_type` are `IP_NAME` and `RESOURCE_NAME`."
+  }
 }
 
-variable "redshift_subnet_group_enabled" {
-  description = "Controls if Redshift Subnet Group should be created."
-  type        = bool
-  default     = false
+variable "dax_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of DAX Subnet Group. `dax_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create DAX Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the DAX Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the DAX Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "redshift_subnet_group_name" {
-  description = "Desired name for the Redshift Subnet Group."
-  type        = string
-  default     = ""
+variable "dms_replication_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of DMS Replication Subnet Group. `dms_replication_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create DMS Replication Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the DMS Replication Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the DMS Replication Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "neptune_subnet_group_enabled" {
-  description = "Controls if Neptune Subnet Group should be created."
-  type        = bool
-  default     = false
+variable "docdb_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of DocumentDB Subnet Group. `docdb_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create DocumentDB Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the DocumentDB Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the DocumentDB Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "neptune_subnet_group_name" {
-  description = "Desired name for the Neptune Subnet Group."
-  type        = string
-  default     = ""
-}
-
-variable "docdb_subnet_group_enabled" {
-  description = "Controls if DocumentDB Subnet Group should be created."
-  type        = bool
-  default     = false
-}
-
-variable "docdb_subnet_group_name" {
-  description = "Desired name for the DocumentDB Subnet Group."
-  type        = string
-  default     = ""
-}
-
-variable "dax_subnet_group_enabled" {
-  description = "Controls if DAX Subnet Group should be created."
-  type        = bool
-  default     = false
+variable "elasticache_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of ElastiCache Subnet Group. `elasticache_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create ElastiCache Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the ElastiCache Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the ElastiCache Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "dax_subnet_group_name" {
-  description = "Desired name for the DAX Subnet Group."
-  type        = string
-  default     = ""
+variable "memorydb_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of MemoryDB Subnet Group. `memorydb_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create MemoryDB Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the MemoryDB Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the MemoryDB Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "dms_replication_subnet_group_enabled" {
-  description = "Controls if DMS Replication Subnet Group should be created."
-  type        = bool
-  default     = false
+variable "neptune_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of Neptune Subnet Group. `neptune_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create Neptune Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the Neptune Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the Neptune Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "dms_replication_subnet_group_name" {
-  description = "Desired name for the DMS Replication Subnet Group."
-  type        = string
-  default     = ""
+variable "rds_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of RDS Subnet Group. `rds_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create RDS Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the RDS Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the RDS Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "memorydb_subnet_group_enabled" {
-  description = "Controls if MemoryDB Subnet Group should be created."
-  type        = bool
-  default     = false
+variable "redshift_subnet_group" {
+  description = <<EOF
+  (Optional) A configuration of Redshift Subnet Group. `redshift_subnet_group` as defined below.
+    (Optional) `enabled` - Whether to create Redshift Subnet Group. Defaults to `false`.
+    (Optional) `name` - The name of the Redshift Subnet Group. If not provided, the value of `name` will be used.
+    (Optional) `description` - The description of the Redshift Subnet Group.
+  EOF
+  type = object({
+    enabled     = optional(bool, false)
+    name        = optional(string)
+    description = optional(string, "Managed by Terraform.")
+  })
+  default  = {}
+  nullable = false
 }
 
-variable "memorydb_subnet_group_name" {
-  description = "Desired name for the MemoryDB Subnet Group."
-  type        = string
-  default     = ""
+variable "timeouts" {
+  description = "(Optional) How long to wait for the subnet group to be created/deleted."
+  type = object({
+    create = optional(string, "10m")
+    delete = optional(string, "20m")
+  })
+  default  = {}
+  nullable = false
 }
 
 variable "tags" {
-  description = "A map of tags to add to all resources."
+  description = "(Optional) A map of tags to add to all resources."
   type        = map(string)
   default     = {}
+  nullable    = false
 }
 
 variable "module_tags_enabled" {
-  description = "Whether to create AWS Resource Tags for the module informations."
+  description = "(Optional) Whether to create AWS Resource Tags for the module informations."
   type        = bool
   default     = true
+  nullable    = false
 }
 
 
@@ -157,19 +287,22 @@ variable "module_tags_enabled" {
 ###################################################
 
 variable "resource_group_enabled" {
-  description = "Whether to create Resource Group to find and group AWS resources which are created by this module."
+  description = "(Optional) Whether to create Resource Group to find and group AWS resources which are created by this module."
   type        = bool
   default     = true
+  nullable    = false
 }
 
 variable "resource_group_name" {
-  description = "The name of Resource Group. A Resource Group name can have a maximum of 127 characters, including letters, numbers, hyphens, dots, and underscores. The name cannot start with `AWS` or `aws`."
+  description = "(Optional) The name of Resource Group. A Resource Group name can have a maximum of 127 characters, including letters, numbers, hyphens, dots, and underscores. The name cannot start with `AWS` or `aws`."
   type        = string
   default     = ""
+  nullable    = false
 }
 
 variable "resource_group_description" {
-  description = "The description of Resource Group."
+  description = "(Optional) The description of Resource Group."
   type        = string
   default     = "Managed by Terraform."
+  nullable    = false
 }