概要
Terraformで変数（variable）の使い方をご紹介させていただきます。
1.tfファイルに定義
terraform {
required_providers {
aws = {
source = "hashicorp/aws"
version = "~> 3.0"
}
}
}
# Configure the AWS Provider
provider "aws" {
region = "ap-northeast-1"
access_key = "xxxxxx"
secret_key = "xxxxxx"
}
resource "aws_vpc" "test-vpc" {
cidr_block = "10.0.0.0/16"
tags = {
Name = "test-vpc"
}
}
variable "test-subnet-cidr-block" {
description = "cidr block for subnet"
default = "10.0.1.0/24"
type = string
}
resource "aws_subnet" "test-subnet" {
vpc_id = aws_vpc.test-vpc.id
cidr_block = var.test-subnet-cidr-block
availability_zone = "ap-northeast-1a"
tags = {
Name = "test-subnet"
}
}
subnetのcidr_blockの値を変数(test-subnet-cidr-block)として、定義します。
terraform applyを実行すると
% terraform apply
Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following
symbols:
+ create
Terraform will perform the following actions:
# aws_subnet.test-subnet will be created
+ resource "aws_subnet" "test-subnet" {
+ arn = (known after apply)
+ assign_ipv6_address_on_creation = false
+ availability_zone = "ap-northeast-1a"
+ availability_zone_id = (known after apply)
+ cidr_block = "10.0.1.0/24"
+ enable_dns64 = false
+ enable_resource_name_dns_a_record_on_launch = false
+ enable_resource_name_dns_aaaa_record_on_launch = false
+ id = (known after apply)
+ ipv6_cidr_block_association_id = (known after apply)
+ ipv6_native = false
+ map_public_ip_on_launch = false
+ owner_id = (known after apply)
+ private_dns_hostname_type_on_launch = (known after apply)
+ tags = {
+ "Name" = "test-subnet"
}
+ tags_all = {
+ "Name" = "test-subnet"
}
+ vpc_id = (known after apply)
}
# aws_vpc.test-vpc will be created
+ resource "aws_vpc" "test-vpc" {
+ arn = (known after apply)
+ cidr_block = "10.0.0.0/16"
+ default_network_acl_id = (known after apply)
+ default_route_table_id = (known after apply)
+ default_security_group_id = (known after apply)
+ dhcp_options_id = (known after apply)
+ enable_classiclink = (known after apply)
+ enable_classiclink_dns_support = (known after apply)
+ enable_dns_hostnames = (known after apply)
+ enable_dns_support = true
+ id = (known after apply)
+ instance_tenancy = "default"
+ ipv6_association_id = (known after apply)
+ ipv6_cidr_block = (known after apply)
+ ipv6_cidr_block_network_border_group = (known after apply)
+ main_route_table_id = (known after apply)
+ owner_id = (known after apply)
+ tags = {
+ "Name" = "test-vpc"
}
+ tags_all = {
+ "Name" = "test-vpc"
}
}
Plan: 2 to add, 0 to change, 0 to destroy.
Do you want to perform these actions?
Terraform will perform the actions described above.
Only 'yes' will be accepted to approve.
Enter a value: yes
aws_vpc.test-vpc: Creating...
aws_vpc.test-vpc: Creation complete after 2s [id=vpc-0ac4ffc8acc29bf57]
aws_subnet.test-subnet: Creating...
aws_subnet.test-subnet: Creation complete after 1s [id=subnet-072e2d3252f4d9bd7]
Apply complete! Resources: 2 added, 0 changed, 0 destroyed.
AWSのコンソールに確認すると、subnetを正常作成しました。
実は変数のdefault値を設定しなくても、大丈夫です。terraform applyを実行際に、コンソールで変数を渡せます。
例えば、変数（test-subnet-cidr-block）のdefault値をコメントアウトします。
variable "test-subnet-cidr-block" {
description = "cidr block for subnet"
#default = "10.0.1.0/24"
type = string
}
resource "aws_subnet" "test-subnet" {
vpc_id = aws_vpc.test-vpc.id
cidr_block = var.test-subnet-cidr-block
availability_zone = "ap-northeast-1a"
tags = {
Name = "test-subnet"
}
}
terraform applyを実行すると以下のメッセージが表示されます。
terraform apply
var.test-subnet-cidr-block
cidr block for subnet
Enter a value:
10.0.2.0/24を渡します。AWS側で10.0.2,0/24サブネットを作成しました。
2.コマンド引数による指定
terraform apply -var "変数名=value"
test.tf内容
resource "aws_vpc" "test-vpc" {
cidr_block = "10.0.0.0/16"
tags = {
Name = "test-vpc"
}
}
variable "test-subnet-cidr-block" {
description = "cidr block for subnet"
#default = "10.0.1.0/24"
type = string
}
resource "aws_subnet" "test-subnet" {
vpc_id = aws_vpc.test-vpc.id
cidr_block = var.test-subnet-cidr-block
availability_zone = "ap-northeast-1a"
tags = {
Name = "test-subnet"
}
}
以下のコマンドを実行すると
terraform apply -var "test-subnet-cidr-block=10.0.100.0/24"
Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following
symbols:
+ create
Terraform will perform the following actions:
# aws_subnet.test-subnet will be created
+ resource "aws_subnet" "test-subnet" {
+ arn = (known after apply)
+ assign_ipv6_address_on_creation = false
+ availability_zone = "ap-northeast-1a"
+ availability_zone_id = (known after apply)
+ cidr_block = "10.0.100.0/24"
+ enable_dns64 = false
+ enable_resource_name_dns_a_record_on_launch = false
+ enable_resource_name_dns_aaaa_record_on_launch = false
+ id = (known after apply)
+ ipv6_cidr_block_association_id = (known after apply)
+ ipv6_native = false
+ map_public_ip_on_launch = false
+ owner_id = (known after apply)
+ private_dns_hostname_type_on_launch = (known after apply)
+ tags = {
+ "Name" = "test-subnet"
}
+ tags_all = {
+ "Name" = "test-subnet"
}
+ vpc_id = (known after apply)
}
# aws_vpc.test-vpc will be created
+ resource "aws_vpc" "test-vpc" {
+ arn = (known after apply)
+ cidr_block = "10.0.0.0/16"
+ default_network_acl_id = (known after apply)
+ default_route_table_id = (known after apply)
+ default_security_group_id = (known after apply)
+ dhcp_options_id = (known after apply)
+ enable_classiclink = (known after apply)
+ enable_classiclink_dns_support = (known after apply)
+ enable_dns_hostnames = (known after apply)
+ enable_dns_support = true
+ id = (known after apply)
+ instance_tenancy = "default"
+ ipv6_association_id = (known after apply)
+ ipv6_cidr_block = (known after apply)
+ ipv6_cidr_block_network_border_group = (known after apply)
+ main_route_table_id = (known after apply)
+ owner_id = (known after apply)
+ tags = {
+ "Name" = "test-vpc"
}
+ tags_all = {
+ "Name" = "test-vpc"
}
}
Plan: 2 to add, 0 to change, 0 to destroy.
Do you want to perform these actions?
Terraform will perform the actions described above.
Only 'yes' will be accepted to approve.
Enter a value: yes
aws_vpc.test-vpc: Creating...
aws_vpc.test-vpc: Creation complete after 2s [id=vpc-0ea24cdeffdec3418]
aws_subnet.test-subnet: Creating...
aws_subnet.test-subnet: Creation complete after 1s [id=subnet-0455e13a3df198517]
Apply complete! Resources: 2 added, 0 changed, 0 destroyed.
AWS側で確認すると10.0.100.0/24サブネットを作成しました。
3.設定ファイルによる変数を指定
terraform.tfvarsというファイルを作成します。以下のコードをterraform.tfvarsに書き込みます。
test-subnet-cidr-block = "10.0.200.0/24"
test.tfファイルに以下のコードを書き込みます。
resource "aws_vpc" "test-vpc" {
cidr_block = "10.0.0.0/16"
tags = {
Name = "test-vpc"
}
}
variable "test-subnet-cidr-block" {
description = "cidr block for subnet"
#default = "10.0.1.0/24"
type = string
}
resource "aws_subnet" "test-subnet" {
vpc_id = aws_vpc.test-vpc.id
cidr_block = var.test-subnet-cidr-block
availability_zone = "ap-northeast-1a"
tags = {
Name = "test-subnet"
}
}
terraform applyを実行すると10.0.200.0/24サブネットを作成しました。
--var-fileで変数定義ファイルを指定できます。
例えば
terraform1.tfvarsというファイルを作成します。以下のコードを書き込みます。
test-subnet-cidr-block = "10.0.199.0/24"
変数ファイルを指定します。
terraform apply --var-file terraform1.tfvars
Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following
symbols:
+ create
Terraform will perform the following actions:
# aws_subnet.test-subnet will be created
+ resource "aws_subnet" "test-subnet" {
+ arn = (known after apply)
+ assign_ipv6_address_on_creation = false
+ availability_zone = "ap-northeast-1a"
+ availability_zone_id = (known after apply)
+ cidr_block = "10.0.199.0/24"
+ enable_dns64 = false
+ enable_resource_name_dns_a_record_on_launch = false
+ enable_resource_name_dns_aaaa_record_on_launch = false
+ id = (known after apply)
+ ipv6_cidr_block_association_id = (known after apply)
+ ipv6_native = false
+ map_public_ip_on_launch = false
+ owner_id = (known after apply)
+ private_dns_hostname_type_on_launch = (known after apply)
+ tags = {
+ "Name" = "test-subnet"
}
+ tags_all = {
+ "Name" = "test-subnet"
}
+ vpc_id = (known after apply)
}
# aws_vpc.test-vpc will be created
+ resource "aws_vpc" "test-vpc" {
+ arn = (known after apply)
+ cidr_block = "10.0.0.0/16"
+ default_network_acl_id = (known after apply)
+ default_route_table_id = (known after apply)
+ default_security_group_id = (known after apply)
+ dhcp_options_id = (known after apply)
+ enable_classiclink = (known after apply)
+ enable_classiclink_dns_support = (known after apply)
+ enable_dns_hostnames = (known after apply)
+ enable_dns_support = true
+ id = (known after apply)
+ instance_tenancy = "default"
+ ipv6_association_id = (known after apply)
+ ipv6_cidr_block = (known after apply)
+ ipv6_cidr_block_network_border_group = (known after apply)
+ main_route_table_id = (known after apply)
+ owner_id = (known after apply)
+ tags = {
+ "Name" = "test-vpc"
}
+ tags_all = {
+ "Name" = "test-vpc"
}
}
Plan: 2 to add, 0 to change, 0 to destroy.
Do you want to perform these actions?
Terraform will perform the actions described above.
Only 'yes' will be accepted to approve.
以上となります。