AWS Load Balancer Terraform 模块 (https://github.com/terraform-aws-modules/terraform-aws-alb): target_group_index = 0，这是什么？

Question

我尝试使用模块，AWS 应用程序和网络负载均衡器（ALB 和 NLB）Terraform 模块，https://github.com/terraform-aws-modules/terraform-aws-alb。有应用负载均衡器的使用示例，见下：

module "alb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "~> 5.0"
  
  name = "my-alb"

  load_balancer_type = "application"

  vpc_id             = "vpc-abcde012"
  subnets            = ["subnet-abcde012", "subnet-bcde012a"]
  security_groups    = ["sg-edcd9784", "sg-edcd9785"]
  
  access_logs = {
    bucket = "my-alb-logs"
  }

  target_groups = [
    {
      name_prefix      = "pref-"
      backend_protocol = "HTTP"
      backend_port     = 80
      target_type      = "instance"
    }
  ]

  https_listeners = [
    {
      port               = 443
      protocol           = "HTTPS"
      certificate_arn    = "arn:aws:iam::123456789012:server-certificate/test_cert-123456789012"
      target_group_index = 0
    }
  ]

  http_tcp_listeners = [
    {
      port               = 80
      protocol           = "HTTP"
      target_group_index = 0
    }
  ]

  tags = {
    Environment = "Test"
  }
}

我知道 target_groups 是一个数组。但是，为什么 target_group_index = 0 而不是 target_group_index = 1 或 target_group_index = 2？索引 0 是什么？

Answer 1

在您发布的示例中，只有一个目标群体 (TG):

  target_groups = [
    {
      name_prefix      = "pref-"
      backend_protocol = "HTTP"
      backend_port     = 80
      target_type      = "instance"
    }
  ]

因此听众使用target_group_index = 0表示他们适用于这个特定的TG。如果您有更多 TG，您可以使用 target_group_index = 1, 2, 3 ... 来指定哪个侦听器适用于每个 TG。