使用 terraform 创建 aws rds 实例？

Question

我尝试使用 terraform 在 AWS 上创建 RDS 实例，并收到以下错误

这段代码可以吗？

resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
}


resource "aws_subnet" "private-subnet1" {
  vpc_id = "${aws_vpc.main.id}"
  cidr_block = "10.0.1.0/24"
}

resource "aws_subnet" "private-subnet2" {
  vpc_id = "${aws_vpc.main.id}"
  cidr_block = "10.0.2.0/24"
}

resource "aws_db_subnet_group" "db-subnet" {
  name       = "DB subnet group"
  subnet_ids = ["${aws_subnet.private-subnet1.id}", "${aws_subnet.private-subnet2.id}"]
}


resource "aws_db_instance" "db" {
  allocated_storage    = "20"
  storage_type         = "gp2"
  engine               = "mysql"
  engine_version       = "5.7.22"
  instance_class       = "db.t2.micro"
  name                 = "mydb"
  username             = "admin"
  password             = "admin"
  parameter_group_name = "db-mysql"
  db_subnet_group_name = "db-subnet"
}

我在应用 terraform 时收到此错误

Error: Error creating DB Subnet Group: DBSubnetGroupDoesNotCoverEnoughAZs: DB Subnet Group doesn't meet availability zone coverage requirement. Please add subnets to cover at least 2 availability zones. Current coverage: 1
    status code: 400, request id: 1bc7f2db-3ad7-41d9-93d0-6cbe3c0adfec

  on terraform.tf line 24, in resource "aws_db_subnet_group" "db-subnet":
  24: resource "aws_db_subnet_group" "db-subnet" {



Error: Error creating DB Instance: DBSubnetGroupNotFoundFault: DBSubnetGroup 'db-subnet' not found.
    status code: 404, request id: a4264af9-c9ac-4241-993f-e8c62e348247

  on terraform.tf line 30, in resource "aws_db_instance" "db":
  30: resource "aws_db_instance" "db" {

Answer 1

这些错误已经很清楚地说明了问题，所以让我们把它们分解一下。

第一个错误与您在创建每个子网时未指定可用区域有关。数据库子网组必须跨越至少 2 个可用区才能实现高可用性，并且您没有为子网指定可用区，因此它们是在同一个子网中创建的。availability_zone使用您所使用的任何区域的不同 az 将参数添加到两个子网。

resource "aws_subnet" "private-subnet1" {
  vpc_id = "${aws_vpc.main.id}"
  cidr_block = "10.0.1.0/24"
  availability_zone = "<an az from your region>"
}

resource "aws_subnet" "private-subnet2" {
  vpc_id = "${aws_vpc.main.id}"
  cidr_block = "10.0.2.0/24"
  availability_zone = "<a different az from your region>"
}

第二个错误与以下事实有关：在您的 中aws_db_instance，您没有引用正在创建的子网组资源，而是按名称指定硬编码的子网组。Terraform 不知道依赖关系，并在尝试创建您定义的依赖项时并行使用不存在的依赖项。将其更改为

db_subnet_group_name = "${aws_db_subnet_group.db-subnet.name}"

第二个错误将会消失，然后您可以解决第一个问题。