Terraform报错：data.aws_subnets不支持vpc_id参数求助

核心错误修复：aws_subnets 数据块参数错误 #

你遇到的Unsupported argument错误，根源是Terraform AWS Provider中aws_subnets数据资源不支持直接用vpc_id作为参数，必须通过filter块筛选指定VPC下的子网。

修正后的aws_subnets数据块代码：

data "aws_subnets" "default" {         
  filter {
    name   = "vpc-id"
    values = [data.aws_vpc.default.id]
  }
}

其他潜在错误修复 #

除上述核心问题外，代码还有几处必须修正的点，否则会触发新的报错：

1. 缺失实例安全组资源 #

aws_launch_configuration.example中引用了aws_security_group.instance.id，但你只定义了负载均衡用的安全组，需添加实例专属安全组：

resource "aws_security_group" "instance" {  
  name = "terraform-example-instance"

  ingress {
    from_port       = var.server_port
    to_port         = var.server_port
    protocol        = "tcp"
    security_groups = [aws_security_group.alb.id]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"] 
  }
}

2. 子网列表引用方式过时 #

新版Terraform中，data.aws_subnets.default.*.id这种引用语法已被弃用，需替换为标准属性ids：

• 修正负载均衡的子网配置：

subnets = data.aws_subnets.default.ids

• 修正自动扩缩容组的可用区子网配置：

vpc_zone_identifier = data.aws_subnets.default.ids

3. AMI ID地域匹配检查 #

你使用的ami-04a7c24c015ef1e4c是首尔地域（ap-northeast-2）的Amazon Linux 2镜像，需确保provider配置的region确实为ap-northeast-2，后续切换地域时需同步更新对应地域的AMI ID。

修复后完整代码 #

provider "aws" {
  access_key = "*****************"
  secret_key = "**********************************"
  region     = "ap-northeast-2"
}

data "aws_vpc" "default" {            
  default = true                   
}

data "aws_subnets" "default" {         
  filter {
    name   = "vpc-id"
    values = [data.aws_vpc.default.id]
  }
}

variable "server_port" {              
  description = "The port the server will use for HTTP requests"
  type        = number
  default     = 80
}

resource "aws_security_group" "alb" {  
  name = "terraform-example-alb"

  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_security_group" "instance" {  
  name = "terraform-example-instance"

  ingress {
    from_port       = var.server_port
    to_port         = var.server_port
    protocol        = "tcp"
    security_groups = [aws_security_group.alb.id]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"] 
  }
}

resource "aws_lb_target_group" "asg" {   
  name     = "terraform-asg-example"
  port     = var.server_port
  protocol = "HTTP"
  vpc_id   = data.aws_vpc.default.id

  health_check {                        
    path                = "/"
    protocol            = "HTTP"
    matcher             = "200"
    interval            = 15
    timeout             = 3
    healthy_threshold   = 2
    unhealthy_threshold = 2
  }
}

resource "aws_lb" "example" {            
  name               = "terraform-asg-example"      
  load_balancer_type = "application"                 
  subnets            = data.aws_subnets.default.ids   
  security_groups    = [aws_security_group.alb.id]    
}

resource "aws_lb_listener" "http" {       
  load_balancer_arn = aws_lb.example.arn
  port              = 80
  protocol          = "HTTP"
  
  default_action {
    type = "fixed-response"

    fixed_response {
      content_type = "text/plain"
      message_body = "404: page not found"
      status_code  = 404
    }
  }
}

resource "aws_lb_listener_rule" "asg" {    
  listener_arn = aws_lb_listener.http.arn
  priority     = 100

  condition {
    path_pattern {
      values = ["*"]
    }
  }

  action {
    type               = "forward"
    target_group_arn   = aws_lb_target_group.asg.arn
  }
}

resource "aws_launch_configuration" "example" {         
  image_id        = "ami-04a7c24c015ef1e4c"              
  instance_type   = "t2.micro"
  security_groups = [aws_security_group.instance.id]    

  user_data = <<-EOF
              #!/bin/bash
              echo "Hello, World" > index.html
              nohup busybox httpd -f -p ${var.server_port} &
              EOF

  lifecycle {
    create_before_destroy = true
  }
}

resource "aws_autoscaling_group" "example" {                       
  launch_configuration = aws_launch_configuration.example.name    
  vpc_zone_identifier  = data.aws_subnets.default.ids            

  target_group_arns = [aws_lb_target_group.asg.arn]              
  health_check_type = "ELB"

  min_size = 2
  max_size = 3

  tag {
    key                 = "Name"
    value               = "terraform-asg-example"
    propagate_at_launch = true  
  }
}

output "alb_dns_name" {                        
  value       = aws_lb.example.dns_name
  description = "The domain name of the load balancer"
}

内容的提问来源于stack exchange，提问作者Sunny