使用 terraform 创建数据库实例

Question

我正在尝试创建 RDS，它只能在 Intranet（又名某些私有子网）中运行。对它的访问将只提供给应用程序。

我在单独的 terraform 文件中创建了 vpc 配置 link 该文件包含vpc配置，routes，nat等。

resource "aws_vpc" "vpc" {
  cidr_block = "10.0.0.0/16"
  enable_dns_support = true
  enable_dns_hostnames = true

  tags {
    Environment = "Dev"
  }
}

resource "aws_subnet" "intranet" {
  vpc_id = "${aws_vpc.vpc.id}"
  cidr_block = "10.0.1.0/24"
  availability_zone = "eu-central-1a"
  tags {
    Name = "Intranet"
    Environemnt = "Dev"
  }
}
....

resource "aws_route_table_association" "intranet" {
   subnet_id = "${aws_subnet.intranet.id}"
   route_table_id = "${aws_route_table.intranet_routetable.id}"
}

对于我的 RDS 配置，我创建了一个具有相似内容的单独 terraform 文件

terraform {
  backend "s3" {
    bucket = "s3-terraform-state-backend"
    region = "eu-central-1"
    key = "common/terraform.tfstate"
  }
}

provider "aws" {
  region = "eu-central-1"
}

resource "aws_vpc" "vpc" {
  cidr_block = "10.0.0.0/16"
  enable_dns_support = true
  enable_dns_hostnames = true

  tags {
    Environment = "Dev"
  }
}

resource "aws_subnet" "intranet" {
  vpc_id = "${aws_vpc.vpc.id}"
  cidr_block = "10.0.1.0/24"
  availability_zone = "eu-central-1a"
  tags {
    Name = "Intranet"
    Environemnt = "Dev"
  }
}

# should contain configuration for common components (rds, sqs etc.)
resource "aws_db_subnet_group" "db_subnet" {
  name = "intranet"
  subnet_ids = ["${aws_subnet.intranet.id}"]
}

resource "aws_db_instance" "core" {
  name = "gj-core-db"
  engine = "postgres"

  allocated_storage = 10
  storage_type = "gp2"
  instance_class = "db.t2.micro"

  db_subnet_group_name = "${aws_db_subnet_group.db_subnet.name}"
}

基本上我从另一个文件复制了 subnet 和 vpc 配置（因为我在这里也需要它）。文件本身在这里 link

当我尝试 apply 配置时出现错误

* aws_db_subnet_group.db_subnet: 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: 44e37b59-1db1-4519-847f-d35f5d150592

我只有一个子网。问题是什么？我应该创建更多子网吗？或者让这个 intranet 子网覆盖更多区域？

Answer 1

一个子网不能跨越多个可用区。您应该创建多个子网并将它们分配给您正在创建的子网组。这是为了保证HA。如果您配置多 AZ RDS 数据库实例并且您的主数据库发生故障，RDS 将确保您的数据库移动到不同的 AZ（具有相同的端点）。

对于子网组，AWS 强制要求每个子网组都应具有分布在多个可用区的子网。可以找到更多详细信息 here。

以下是 AWS 文档中的相关部分。

Each DB subnet group should have subnets in at least two Availability Zones in a given region. When creating a DB instance in VPC, you must select a DB subnet group. Amazon RDS uses that DB subnet group and your preferred Availability Zone to select a subnet and an IP address within that subnet to associate with your DB instance. If the primary DB instance of a Multi-AZ deployment fails, Amazon RDS can promote the corresponding standby and subsequently create a new standby using an IP address of the subnet in one of the other Availability Zones

Answer 2

我也陷入了同样的境地 problem/question，尽管接受的答案感觉正确，但我想增加它来回答@Davos 评论中的以下问题：

“如果您正在测试/开发并想要一个 single-AZ RDS，RDS 仍然需要一个子网组（并且所有子网组都有多个 AZ），即使它只使用一个 AZ？”

是的，确实如此。这似乎是一个准备，以防将来你想将 RDS 转换为 Multi-AZ。

可以找到更多详细信息here（检查“第 3 步”）

使用 terraform 创建数据库实例

creating db instance using terraform

amazon-web-services

terraform