Terraform错误：subnet_ids vpc模块的属性值类型不正确

Question

在版本12.24中运行Terraform Plan时，出现错误：属性值类型不正确。

Error: Incorrect attribute value type

  on .terraform/modules/app/main.tf line 134, in resource "aws_db_subnet_group" "db_subnet_group":
 134:   subnet_ids  = var.subnets
    |----------------
    | var.subnets is list of tuple with 1 element

Inappropriate value for attribute "subnet_ids": incorrect set element type:
string required.

tf文件中的代码：

resource "aws_db_subnet_group" "db_subnet_group" {
  count = "${var.create_subnet_group ? 1 : 0}"

  name_prefix = "${var.name}-"
  description = "Database subnet group for ${var.name}"
  subnet_ids  = var.subnets

variables.tf文件：

variable "subnets" {
  description = "Subnets for RDS Instances"
  type        = "list"
}

我该如何解决？

Answer 1

错误消息表明您拥有list of tuple with 1 element，这意味着var.subnets的形式为：

variable "subnets" {
  description = "Subnets for RDS Instances"
  type        = "list"
  default = [["subnet-070db0eee8c5f3bb1", "subnet-01e76559b44d06aa3"]]
}

因此，要使用内部列表（即元组），您必须：

resource "aws_db_subnet_group" "db_subnet_group" {
  
  # other attributes not shown

  subnet_ids  = var.subnets[0]
}