如何通过 terraform_remote_state 获取 VPC 子网 ID？

Question

我的 vpc 状态文件位于 dev/vpc/main/terraform.tfstate。我想使用 vpc 中的私有子网来预置 mariaDB。我收到错误：

错误：错误运行计划：发生 1 个错误：

module.csc_db_sbnet_group.var.db_subnet_group_ids: element: element() 不能与空列表一起使用：

${元素(data.terraform_remote_state.vpc_subnets_ids.vpc_private_subnets_ids,0)}

MariaDB代码（注：MariaDB代码有自己的terrafrom状态文件）：

data_sources.tf: 

data "terraform_remote_state" "vpc_subnets_ids" {
  backend = "s3"

  config {
    bucket = "dev-terraform-state"
    key    = "dev/vpc/main/terraform.tfstate"
    region = "us-west-2"
  }
}

resources.tf:
module "csc_db_sbnet_group" {
  source               = "modules/rds-subnet-group"
  db_subnet_group_name = "${var.db_subnet_group_name}"
  db_subnet_group_ids  = ["${element(data.terraform_remote_state.vpc_subnets_ids.vpc_private_subnets_ids,0)}", "${element(data.terraform_remote_state.vpc_subnets_ids.vpc_private_subnets_ids,1)}"]
}

VPC 代码：

resources.tf:

module "vpc" {
  source = "modules/vpc"

  aws_region   = "${var.region}"
  vpc_tag_name = "${var.vpc_name}"
  vpc_cidr     = "${var.vpccidr}"

  private-subnet-mapping = ["${var.private_az_subnets_cidr}"]
  public-subnet-mapping  = ["${var.public_az_subnets_cidr}"]
}

resource "aws_subnet" "add_private_subnets" {
  count = "${length(var.private-subnet-mapping)}"

  cidr_block        = "${lookup(var.private-subnet-mapping[count.index], "cidr")}"
  vpc_id            = "${module.vpc.vpc_id}"
  availability_zone = "${lookup(var.private-subnet-mapping[count.index], "az")}"

  tags = {
    Name = "${lookup(var.private-subnet-mapping[count.index], "name")}"
    BU   = "${lookup(var.private-subnet-mapping[count.index], "BU")}"
  }
}

outputs.tf
output "vpc_private_subnets_ids" {
  value = ["${aws_subnet.add_private_subnets.*.id}"]
}

output "vpc_private_subnets_cidrs" {
  value = ["${aws_subnet.add_private_subnets.*.cidr_block}"]
}

当我配置 MariaDB 时，我想使用 VPC 代码中配置的私有子网。但是，它抱怨说，

module.csc_db_sbnet_group.var.db_subnet_group_ids: element: element() 不能与空列表一起使用：

${元素(data.terraform_remote_state.vpc_subnets_ids.vpc_private_subnets_ids,0)}

Answer 1

我在下面为 VPC 添加了代码并解决了问题。

data "aws_subnet_ids" "private_subnet_ids" {
  vpc_id            = "${module.vpc.vpc_id}"
}
data "aws_subnet" "private_subnet" {
  count = "${length(data.aws_subnet_ids.private_subnet_ids.ids)}"
  id    = "${data.aws_subnet_ids.private_subnet_ids.ids[count.index]}"
}

如何通过 terraform_remote_state 获取 VPC 子网 ID？

How to get VPC subnet ids via terraform_remote_state?

terraform

terraform-provider-aws