Terraform - Module当中使用output输出变量

output不仅仅只是在console当中输出变量，也能作为module 输出变量让其他的module使用

如何使用output在console当中输出变量？
https://www.pangzai.win/terraform-%e7%bb%93%e5%90%88%e5%a4%9a%e4%b8%aaoutput%e4%bd%bf%e7%94%a8zipmap-function%e5%88%b6%e4%bd%9c%e6%96%b0%e7%9a%84map/

以下的使用案例是
1. 使用module vpc创建 vpc，然后输出subnet id
2. 使用module ec2创建ec2 , 并且创建在这个subnet id之上

使用案例

（vpc module）创建vpc和subnet , 输出public_subnet_id
路径： modules/vpc/main.tf

terraform {
  required_version = ">= 1.0.0" # Ensure that the Terraform version is 1.0.0 or higher

  required_providers {
    aws = {
      source  = "hashicorp/aws" # Specify the source of the AWS provider
      version = "~> 5.0"        # Use a version of the AWS provider that is compatible with version
    }
  }
}

variable "environment" {}
variable "region" {}

output "public_subnet_id" {
  value = aws_subnet.public_subnet_1.id
}

##############################
# Create VPC with IPv6 enabled
##############################
resource "aws_vpc" "main" {
  cidr_block                     = "14.2.0.0/16"
  assign_generated_ipv6_cidr_block = true
  enable_dns_support             = true
  enable_dns_hostnames           = true

  tags = {
    Name        = "vpc-${var.environment}"
    Environment = var.environment  # Group resources by tags
  }
}

##############################
# Create Internet Gateway and attach to VPC
##############################
resource "aws_internet_gateway" "igw" {
  vpc_id = aws_vpc.main.id

  tags = {
    Name        = "igw-${var.environment}"
    Environment = var.environment
  }
}

##############################
# Create Public Subnets with IPv6
##############################
resource "aws_subnet" "public_subnet_1" {
  vpc_id                  = aws_vpc.main.id
  cidr_block              = "14.2.1.0/24"
  availability_zone       = "${var.region}a"
  map_public_ip_on_launch = true
  enable_dns64 = true
  enable_resource_name_dns_aaaa_record_on_launch = true
  enable_resource_name_dns_a_record_on_launch = true

  # Calculate an IPv6 subnet from the VPC's IPv6 block
  ipv6_cidr_block         = cidrsubnet(aws_vpc.main.ipv6_cidr_block, 8, 0)

  tags = {
    Name        = "${var.environment}-public-a"
    Environment = var.environment
    "karpenter.sh/discovery" = "${var.environment}-eks"
  }
}

resource "aws_subnet" "public_subnet_2" {
  vpc_id                  = aws_vpc.main.id
  cidr_block              = "14.2.2.0/24"
  availability_zone       = "${var.region}b"
  map_public_ip_on_launch = true
  enable_dns64 = true
  enable_resource_name_dns_aaaa_record_on_launch = true
  enable_resource_name_dns_a_record_on_launch = true

  ipv6_cidr_block         = cidrsubnet(aws_vpc.main.ipv6_cidr_block, 8, 1)

  tags = {
    Name        = "${var.environment}-public-b"
    Environment = var.environment
    "karpenter.sh/discovery" = "${var.environment}-eks"
  }
}

##############################
# Create Private Subnets with IPv6
##############################
resource "aws_subnet" "private_subnet_1" {
  vpc_id                  = aws_vpc.main.id
  cidr_block              = "14.2.101.0/24"
  availability_zone       = "${var.region}a"
  map_public_ip_on_launch = false
  enable_dns64 = true
  enable_resource_name_dns_aaaa_record_on_launch = true
  enable_resource_name_dns_a_record_on_launch = true

  ipv6_cidr_block         = cidrsubnet(aws_vpc.main.ipv6_cidr_block, 8, 2)

  tags = {
    Name        = "${var.environment}-private-a"
    Environment = var.environment
    "karpenter.sh/discovery" = "${var.environment}-eks"
  }
}

resource "aws_subnet" "private_subnet_2" {
  vpc_id                  = aws_vpc.main.id
  cidr_block              = "14.2.102.0/24"
  availability_zone       = "${var.region}b"
  map_public_ip_on_launch = false
  enable_dns64 = true
  enable_resource_name_dns_aaaa_record_on_launch = true
  enable_resource_name_dns_a_record_on_launch = true

  ipv6_cidr_block         = cidrsubnet(aws_vpc.main.ipv6_cidr_block, 8, 3)

  tags = {
    Name        = "${var.environment}-private-b"
    Environment = var.environment
    "karpenter.sh/discovery" = "${var.environment}-eks"
  }
}

##############################
# Configure Public Subnet Default Route Table and attach IGW with IPv6 route
##############################
resource "aws_route_table" "public_rt" {
  #default_route_table_id = aws_vpc.main.default_route_table_id
  vpc_id = aws_vpc.main.id

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.igw.id
  }

  # Add IPv6 route
  route {
    ipv6_cidr_block = "::/0"
    gateway_id      = aws_internet_gateway.igw.id
  }

  tags = {
    Name        = "${var.environment}-public-table"
    Environment = var.environment
  }
}

resource "aws_route_table_association" "public_subnet_1_association" {
  subnet_id      = aws_subnet.public_subnet_1.id
  #route_table_id = aws_default_route_table.public_rt.id
  route_table_id = aws_route_table.public_rt.id
}

resource "aws_route_table_association" "public_subnet_2_association" {
  subnet_id      = aws_subnet.public_subnet_2.id
  #route_table_id = aws_default_route_table.public_rt.id
  route_table_id = aws_route_table.public_rt.id
}

##############################
# Create NAT Gateway (deployed in the Public Subnet) for outbound access from the Private Subnets
##############################
# Uncomment and configure if you want NAT Gateway for private subnets
# resource "aws_eip" "nat_eip" {
#   domain = "vpc"
# }
#
# resource "aws_nat_gateway" "nat" {
#   allocation_id = aws_eip.nat_eip.id
#   subnet_id     = aws_subnet.public_subnet_1.id
#
#   tags = {
#     Name = "my-nat-gateway"
#   }
# }

##############################
# Create Private Subnet Route Table and attach NAT Gateway (if applicable)
##############################
resource "aws_route_table" "private_rt" {
  vpc_id = aws_vpc.main.id

  # For IPv4 NAT Gateway route (if NAT is enabled)
  # route {
  #   cidr_block     = "0.0.0.0/0"
  #   nat_gateway_id = aws_nat_gateway.nat.id
  # }

  tags = {
    Name        = "${var.environment}-private-table"
    Environment = var.environment
  }
}

resource "aws_route_table_association" "private_subnet_1_association" {
  subnet_id      = aws_subnet.private_subnet_1.id
  route_table_id = aws_route_table.private_rt.id
}

resource "aws_route_table_association" "private_subnet_2_association" {
  subnet_id      = aws_subnet.private_subnet_2.id
  route_table_id = aws_route_table.private_rt.id
}

##############################
# Create VPC Endpoint for S3 (Gateway type)
##############################
resource "aws_vpc_endpoint" "s3_endpoint" {
  vpc_id            = aws_vpc.main.id
  service_name      = "com.amazonaws.${var.region}.s3"
  vpc_endpoint_type = "Gateway"

  # Attach the S3 Endpoint to both Public and Private route tables
  route_table_ids = [
    aws_route_table.public_rt.id,
    aws_route_table.private_rt.id,
  ]

  tags = {
    Name        = "${var.environment}-vpc-endpoint"
    Environment = var.environment
  }
}

2. （ec2 module）使用vpc输出的subnet_net_id 之上创建ec2
路径： modules/ec2/main.tf

terraform {
  required_version = ">= 1.0.0" # Ensure that the Terraform version is 1.0.0 or higher

  required_providers {
    aws = {
      source  = "hashicorp/aws" # Specify the source of the AWS provider
      version = "~> 5.0"        # Use a version of the AWS provider that is compatible with version
    }
  }
}

data "aws_ami" "latest_amazon_linux" {
  most_recent = true
  owners      = ["amazon"]

  filter {
    name   = "architecture"
    values = ["x86_64"]
  }
  filter {
    name   = "name"  // 找出最新版本的 Amazon Linux 2023 AMI
    values = ["al2023-ami-2023*"]
  }
}

resource "aws_instance" "myec2" {
    ami = data.aws_ami.latest_amazon_linux.id
    instance_type = var.instance_type
    subnet_id = var.subnet_id
}

variable "subnet_id" {}
variable "instance_type" {}

3. 在root module当中使用

terraform {
  required_version = ">= 1.0.0" # Ensure that the Terraform version is 1.0.0 or higher

  required_providers {
    aws = {
      source  = "hashicorp/aws" # Specify the source of the AWS provider
      version = "~> 5.0"        # Use a version of the AWS provider that is compatible with version
    }
  }
}

variable "region" {
  default = "ap-southeast-5"
}

provider "aws" {
  region = var.region
}

output "current_region" {
  value = var.region
}

module "vpc" {
  source = "./modules/vpc"
  region = var.region
  environment = "test"
}

module "ec3" {
  source = "./modules/ec2"
  subnet_id = module.vpc.public_subnet_id
  instance_type = "t3.micro"
}

以下是结构图，ec2使用vpc当中创建的eip