如何通过terraform_remote_state获取VPC子网ID？

问题描述

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

错误：错误的运行计划：发生了1个错误：

• module.csc_db_sbnet_group.var.db_subnet_group_ids：element：element（）不得与以下列表中的空列表一起使用：

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

MariaDB代码（注意：MariaDB代码具有自己的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}"]
}

我提供MariaDB时，我想使用VPC代码中提供的专用子网。但是，它抱怨，

• module.csc_db_sbnet_group.var.db_subnet_group_ids：element：element（）不得与以下列表中的空列表一起使用：

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

解决方法

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]}"
}