実践Terraform ch3 基本構文
変数
variable "example_instance_type" { default = "t3.micro" } resource "aws_instance" "example" { ami = "ami-0c3fd0f5d33134a76" instance_type = var.example_instance_type }
- デフォルトで実行すると、t3.microインスタンスが生える
docker-compose run terraform apply
docker-compose run terraform plan -var 'example_instance_type=t3.nano'
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.
aws_instance.example: Refreshing state... [id=i-093eea25a835afe36]
------------------------------------------------------------------------
An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
~ update in-place
Terraform will perform the following actions:
# aws_instance.example will be updated in-place
~ resource "aws_instance" "example" {
ami = "ami-0c3fd0f5d33134a76"
...
instance_state = "running"
~ instance_type = "t3.micro" -> "t3.nano"
ipv6_address_count = 0
...
}
}
Plan: 0 to add, 1 to change, 0 to destroy.
------------------------------------------------------------------------
Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.
- 実行
docker-compose run terraform apply -var 'example_instance_type=t3.nano'
ローカル変数
locals {
example_ami = "ami-0c3fd0f5d33134a76"
example_instance_type = "t3.nano"
}
resource "aws_instance" "example" {
ami = local.example_ami
instance_type = local.example_instance_type
}
resource "aws_instance" "example2" {
ami = local.example_ami
instance_type = local.example_instance_type
}
- コマンドラインで上書きできないやつ
出力値
- 生成したEC2インスタンスのIDを出力する
locals {
example_instance_type = "t3.micro"
}
resource "aws_instance" "example" {
ami = "ami-0c3fd0f5d33134a76"
instance_type = local.example_instance_type
}
output "example_instance_id" {
value = aws_instance.example.id
}
docker-compose run terraform apply
... Apply complete! Resources: 0 added, 1 changed, 0 destroyed. Outputs: example_instance_id = i-093eea25a835afe36
データソース
ami = "ami-0c3fd0f5d33134a76"
data "aws_ami" "recent_amazon_linux_2" {
most_recent = true
owners = ["amazon"]
filter {
name = "name"
values = ["amzn2-ami-hvm-2.0.*-x86_64-gp2"]
}
filter {
name = "state"
values = ["available"]
}
}
resource "aws_instance" "example" {
ami = data.aws_ami.recent_amazon_linux_2.image_id
instance_type = "t3.micro"
}
output "example_ami" {
value = data.aws_ami.recent_amazon_linux_2.image_id
}
... Outputs: example_ami = ami-0af1df87db7b650f4
- 確かに最新が取ってこれた (2020/3/4現在)
- wildcard が使える
?*
プロバイダ
provider "aws" {
region = "ap-northeast-1"
}
- ここまで、↑が暗黙的に検出・補完されていた
参照
resource "aws_security_group" "example_ec2" {
name = "example-ec2"
ingress {
from_port = 80
to_port = 80
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
egress {
from_port = 0
to_port = 0
protocol = "-1"
cidr_blocks = ["0.0.0.0/0"]
}
}
resource "aws_instance" "example" {
ami = data.aws_ami.recent_amazon_linux_2.image_id
instance_type = "t3.micro"
vpc_security_group_ids = [aws_security_group.example_ec2.id]
user_data = <<EOF
#!/bin/bash
yum install -y httpd
systemctl start httpd.service
EOF
}
- セキュリティグループリソース
aws_security_group.example_ec2を作成し、EC2インスタンスリソースaws_instance.exampleの設定に渡している
docker-compose run terraform apply
🎉
組み込み関数
user_data = <<EOF
#!/bin/bash
yum install -y httpd
systemctl start httpd.service
EOF
- ↑これをやめたい
user_data.shファイルに切り出して
#!/bin/bash yum install -y httpd systemctl start httpd.service
file(path)関数で読み込む
user_data = file("./user_data.sh")
モジュール
- tfファイルを分割して管理したい
main.tf
module "web_server" {
source = "./http_server"
instance_type = "t3.micro"
}
output "example_public_dns" {
value = module.web_server.public_dns
}
http_server/main.tf
module "security_group" {
source = "../security_group"
}
variable "instance_type" {}
resource "aws_instance" "default" {
ami = data.aws_ami.recent_amazon_linux_2.image_id
instance_type = var.instance_type
vpc_security_group_ids = [module.security_group.id]
user_data = file("./user_data.sh")
}
data "aws_ami" "recent_amazon_linux_2" {
most_recent = true
owners = ["amazon"]
filter {
name = "name"
values = ["amzn2-ami-hvm-2.0.*-x86_64-gp2"]
}
filter {
name = "state"
values = ["available"]
}
}
output "public_dns" {
value = aws_instance.default.public_dns
}
security_group/main.tf
resource "aws_security_group" "default" {
name = "ec2"
ingress {
from_port = 80
to_port = 80
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
egress {
from_port = 0
to_port = 0
protocol = "-1"
cidr_blocks = ["0.0.0.0/0"]
}
}
output "id" {
value = aws_security_group.default.id
}
docker-compose run terraform plan
Error: Module not installed
on main.tf line 1:
1: module "web_server" {
This module is not yet installed. Run "terraform init" to install all modules
required by this configuration.
- モジュールを読み込む必要がある
docker-compose run terraform get docker-compose run terraform plan docker-compose run terraform apply
... module.web_server.module.security_group.aws_security_group.default: Creating... module.web_server.module.security_group.aws_security_group.default: Creation complete after 2s [id=sg-08bf3a304ffa6a3a8] module.web_server.aws_instance.default: Creating... module.web_server.aws_instance.default: Still creating... [10s elapsed] module.web_server.aws_instance.default: Creation complete after 12s [id=i-03665de43ec019e2d] Apply complete! Resources: 2 added, 0 changed, 0 destroyed.
