通过Terraform自动搭建经典负载均衡架构

背景信息

HashiCorp Terraform是一个IT基础架构自动化编排工具，可以用代码来管理维护IT资源。Terraform的命令行接口提供了一种简单机制，用于将配置文件部署到阿里云或其他任意支持的云上，并对其进行版本控制。它编写了描述云资源拓扑的配置文件中的基础结构，例如虚拟机、存储账户和网络接口。

产品架构

通过Terraform自动搭建经典负载均衡架构的示意图如下：

相关资源

通过以下云资源的配置信息搭建经典架构：

典型案例

以下示例定义了一个用于一键部署经典负载均衡架构的Terraform模板，Terraform将基于该模板首先创建出资源所需要的网络环境VPC、vSwitch、SLB以及安全组，然后在该网络环境中创建ECS，RDS等计算资源，最后在SLB中创建监听并将ECS实例挂载到SLB上，成为其后端服务器。

// Images data source to get image_id
data "alicloud_images" "default" {
  most_recent = true
  owners      = "system"
  name_regex  = "${var.image_name_regex}"
}

// Instance_types data source to get instance_type
data "alicloud_instance_types" "default" {
  cpu_core_count = "${var.cpu_core_count}"
  memory_size    = "${var.memory_size}"
}

// Zones data source to get availability_zone
data "alicloud_zones" "default" {
  available_instance_type     = "${data.alicloud_instance_types.default.instance_types.0.id}"
  available_resource_creation = "Rds"
}

// If you do not specify vpc_id, the module will create a new VPC
resource "alicloud_vpc" "vpc" {
  count      = "${var.vpc_id == "" ? 1 : 0}"
  cidr_block = "${var.vpc_cidr}"
  name       = "${var.vpc_name == "" ? var.resource_group_name : var.vpc_name}"
}

// Create vSwitches
resource "alicloud_vswitch" "vswitches" {
  count             = "${length(var.vswitch_ids) > 0 ? 0 : length(var.vswitch_cidrs)}"
  vpc_id            = "${var.vpc_id == "" ? join("", alicloud_vpc.vpc.*.id) : var.vpc_id}"
  cidr_block        = "${element(var.vswitch_cidrs, count.index)}"
  availability_zone = "${lookup(data.alicloud_zones.default.zones[count.index], "id")}"
  name              = "${var.vswitch_name_prefix == "" ? format("%s-%s", var.resource_group_name, format(var.number_format, count.index+1)) : format("%s-%s", var.vswitch_name_prefix, format(var.number_format, count.index+1))}"
}

// Security Group Resource for Module
resource "alicloud_security_group" "default" {
  vpc_id = "${var.vpc_id == "" ? join("", alicloud_vpc.vpc.*.id) : var.vpc_id}"
  name   = "${var.group_name == "" ? var.resource_group_name : var.group_name}"
}

// ECS Instance Resource for Web Tier
resource "alicloud_instance" "web" {
  count = "${var.number_of_web_instances}"

  image_id        = "${var.image_id == "" ? data.alicloud_images.default.images.0.id : var.image_id }"
  instance_type   = "${var.instance_type == "" ? data.alicloud_instance_types.default.instance_types.0.id : var.instance_type}"
  security_groups = ["${ alicloud_security_group.default.id }"]

  instance_name = "${var.number_of_web_instances < 2 ? var.web_instance_name : format("%s-%s", var.web_instance_name, format(var.number_format, count.index+1))}"
  host_name     = "${var.number_of_web_instances < 2 ? var.web_host_name : format("%s-%s", var.web_host_name, format(var.number_format, count.index+1))}"

  internet_charge_type       = "${var.internet_charge_type}"
  internet_max_bandwidth_out = "${var.internet_max_bandwidth_out}"

  instance_charge_type = "${var.instance_charge_type}"
  system_disk_category = "${var.system_category}"
  system_disk_size     = "${var.system_size}"

  password = "${var.ecs_password}"

  vswitch_id = "${length(var.vswitch_ids) > 0 ? element(split(",", join(",", var.vswitch_ids)), count.index%length(split(",", join(",", var.vswitch_ids)))) : length(var.vswitch_cidrs) < 1 ? "" : element(split(",", join(",", alicloud_vswitch.vswitches.*.id)), count.index%length(split(",", join(",", alicloud_vswitch.vswitches.*.id))))}"

  period      = "${var.period}"
  period_unit = "${var.period_unit}"
}

// ECS Instance Resource for app Tier
resource "alicloud_instance" "app" {
  count = "${var.number_of_app_instances}"

  image_id        = "${var.image_id == "" ? data.alicloud_images.default.images.0.id : var.image_id }"
  instance_type   = "${var.instance_type == "" ? data.alicloud_instance_types.default.instance_types.0.id : var.instance_type}"
  security_groups = ["${alicloud_security_group.default.id}"]

  instance_name = "${var.number_of_app_instances < 2 ? var.app_instance_name : format("%s-%s", var.app_instance_name, format(var.number_format, count.index+1))}"
  host_name     = "${var.number_of_app_instances < 2 ? var.app_host_name : format("%s-%s", var.app_host_name, format(var.number_format, count.index+1))}"

  internet_charge_type       = "${var.internet_charge_type}"
  internet_max_bandwidth_out = "${var.internet_max_bandwidth_out}"

  instance_charge_type = "${var.instance_charge_type}"
  system_disk_category = "${var.system_category}"
  system_disk_size     = "${var.system_size}"

  password = "${var.ecs_password}"

  vswitch_id = "${length(var.vswitch_ids) > 0 ? element(split(",", join(",", var.vswitch_ids)), count.index%length(split(",", join(",", var.vswitch_ids)))) : length(var.vswitch_cidrs) < 1 ? "" : element(split(",", join(",", alicloud_vswitch.vswitches.*.id)), count.index%length(split(",", join(",", alicloud_vswitch.vswitches.*.id))))}"

  period      = "${var.period}"
  period_unit = "${var.period_unit}"
}

// SLB Instance Resource for intranet
resource "alicloud_slb" "intranet" {
  internet = false
  name     = "${var.slb_intranet_name == "" ? var.resource_group_name : var.slb_intranet_name}"
}

resource "alicloud_slb_attachment" "intranet" {
  load_balancer_id = "${alicloud_slb.intranet.id}"
  instance_ids     = ["${alicloud_instance.web.*.id}", "${alicloud_instance.app.*.id}"]
}

// SLB Instance Resource for internet
resource "alicloud_slb" "internet" {
  internet  = true
  bandwidth = "${var.slb_max_bandwidth}"
  name      = "${var.slb_internet_name == "" ? var.resource_group_name : var.slb_internet_name}"
}

resource "alicloud_slb_attachment" "internet" {
  load_balancer_id = "${alicloud_slb.internet.id}"
  instance_ids     = ["${alicloud_instance.web.*.id}"]
}

// RDS Resource
resource "alicloud_db_instance" "default" {
  count            = "${var.number_of_rds_instances}"
  instance_name    = "${var.number_of_rds_instances < 2 ? var.rds_name_prefix : format("%s-%s", var.rds_name_prefix, format(var.number_format, count.index+1))}"
  engine           = "${var.engine}"
  engine_version   = "${var.engine_version}"
  instance_type    = "${var.db_instance_type}"
  instance_storage = "${var.storage}"
  vswitch_id       = "${length(var.vswitch_ids) > 0 ? element(split(",", join(",", var.vswitch_ids)), count.index%length(split(",", join(",", var.vswitch_ids)))) : length(var.vswitch_cidrs) < 1 ? "" : element(split(",", join(",", alicloud_vswitch.vswitches.*.id)), count.index%length(split(",", join(",", alicloud_vswitch.vswitches.*.id))))}"
  security_ips     = ["${alicloud_instance.app.*.private_ip}"]
}

resource "alicloud_db_account" "default" {
  count       = "${var.number_of_rds_instances}"
  instance_id = "${element(alicloud_db_instance.default.*.id, count.index)}"
  name        = "${var.rds_account_name_prefix}${count.index}"
  password    = "${var.rds_account_password}"
}

resource "alicloud_db_database" "default" {
  count       = "${var.number_of_rds_instances}"
  instance_id = "${element(alicloud_db_instance.default.*.id, count.index)}"
  name        = "${var.rds_database_name_prefix}_${count.index}"
}

// OSS Resource
resource "alicloud_oss_bucket" "default" {
  bucket = "${var.bucket_name == "" ? var.resource_group_name : var.bucket_name}"
  acl    = "${var.bucket_acl}"
}

运行Terraform模板

参考以下步骤，运行该模板：

1. 通过环境变量设置AccessKey ID、AccessKey Secret和地域。

   您可以登录访问控制管理控制台创建并查看AccessKey，或者联系系统管理员获取AccessKey。

   $ export ALICLOUD_ACCESS_KEY=XXXXX
   $ export ALICLOUD_SECRET_KEY=XXXXX
   $ export ALICLOUD_REGION=regionID 

2. 下载完整模板。

   $ git clone https://github.com/terraform-alicloud-modules/terraform-alicloud-classic-load-balance.git

3. 运行以下的Terraform命令，完成资源的创建。
   1. 进入模板根目录：

       $ cd terraform-alicloud-classic-load-balance

   2. 预览要创建的资源：

      $ terraform plan

   3. 创建资源：

      $ terraform apply

   4. 释放已创建的资源：

      $ terraform destroy