タダです.

Aurora AutoScaling をスケジュール実行したいことありますよね.AWS CLI でもできますが,Terraform で設定をしてみたのでこの記事でまとめます.

Terraform のコード

AutoScaling のスケジュール設定は aws_appautoscaling_scheduled_action で行います.AM 10時に2台にスケールアウトし,PM20時に1台にスケールインするポリシーを設定してみます.

resource "aws_appautoscaling_scheduled_action" "scaleout" {
  name               = "blog-test scale-out by cron"
  service_namespace  = "rds"
  resource_id        = "cluster:blog-test"
  scalable_dimension = "rds:cluster:ReadReplicaCount"
  schedule           = "cron(0 10 * * ? *)"
  timezone           = "Asia/Tokyo"
  scalable_target_action {
    min_capacity = 2
    max_capacity = 4
  }
}
resource "aws_appautoscaling_scheduled_action" "scalein" {
  name               = "blog-test scale-in by cron"
  service_namespace  = "rds"
  resource_id        = "cluster:blog-test"
  scalable_dimension = "rds:cluster:ReadReplicaCount"
  schedule           = "cron(0 20 * * ? *)"
  timezone           = "Asia/Tokyo"
  scalable_target_action {
    min_capacity = 1
    max_capacity = 4
  }
}

関連情報

registry.terraform.io

上記の定義を適用すると以下のようになります.

Terraform will perform the following actions:

  # aws_appautoscaling_scheduled_action.scalein will be created
  + resource "aws_appautoscaling_scheduled_action" "scalein" {
      + arn                = (known after apply)
      + id                 = (known after apply)
      + name               = "blog-test scale-in by cron"
      + resource_id        = "cluster:blog-test"
      + scalable_dimension = "rds:cluster:ReadReplicaCount"
      + schedule           = "cron(0 20 * * ? *)"
      + service_namespace  = "rds"
      + timezone           = "Asia/Tokyo"

      + scalable_target_action {
          + max_capacity = "4"
          + min_capacity = "1"
        }
    }

  # aws_appautoscaling_scheduled_action.scaleout will be created
  + resource "aws_appautoscaling_scheduled_action" "scaleout" {
      + arn                = (known after apply)
      + id                 = (known after apply)
      + name               = "blog-test scale-out by cron"
      + resource_id        = "cluster:blog-test"
      + scalable_dimension = "rds:cluster:ReadReplicaCount"
      + schedule           = "cron(0 10 * * ? *)"
      + service_namespace  = "rds"
      + timezone           = "Asia/Tokyo"

      + scalable_target_action {
          + max_capacity = "4"
          + min_capacity = "2"
        }
    }

Plan: 2 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

aws_appautoscaling_scheduled_action.scalein-nighttime: Creating...
aws_appautoscaling_scheduled_action.scaleout-nighttime: Creating...
aws_appautoscaling_scheduled_action.scalein-nighttime: Creation complete after 0s [id=scalein-nighttime-rds-cluster:blog-test]
aws_appautoscaling_scheduled_action.scaleout-nighttime: Creation complete after 0s [id=scaleout-nighttime-rds-cluster:blog-test]

Apply complete! Resources: 2 added, 0 changed, 0 destroyed.

設定した AutoScaling Policy を確認する

設定した AutoScaling Policy が意図通りに入っているかを確認してみます.aws application-autoscaling describe-scheduled-actions --service-namespace rds を実行することで Aurora AutoScaling のスケジュールしたAutoScaling ポリシーを確認できます.

❯ aws application-autoscaling describe-scheduled-actions --service-namespace rds
{
    "ScheduledActions": [
        {
            "ScheduledActionName": "blog-test scale-out by cron",
            "ScheduledActionARN": "arn:aws:autoscaling:ap-northeast-1:1234567891011:scheduledAction:c55ffe6e-2bb2-4591-9abe-ab12c6414ef0:resource/rds/cluster:blog-test:scheduledActionName/blog-test >
            "ServiceNamespace": "rds",
            "Schedule": "cron(0 10 * * ? *)",
            "Timezone": "Asia/Tokyo",
            "ResourceId": "cluster:blog-test",
            "ScalableDimension": "rds:cluster:ReadReplicaCount",
            "ScalableTargetAction": {
                "MinCapacity": 2,
                "MaxCapacity": 4
            },
            "CreationTime": "2023-12-02T17:00:02.052000+09:00"
        },
        {
            "ScheduledActionName": "blog-test scale-in by cron",
            "ScheduledActionARN": "arn:aws:autoscaling:ap-northeast-1:1234567891011:scheduledAction:c55ffe6e-2bb2-4591-9abe-ab12c6414ef0:resource/rds/cluster:blog-test:scheduledActionName/blog-test >
            "ServiceNamespace": "rds",
            "Schedule": "cron(0 20 * * ? *)",
            "Timezone": "Asia/Tokyo",
            "ResourceId": "cluster:blog-test",
            "ScalableDimension": "rds:cluster:ReadReplicaCount",
            "ScalableTargetAction": {
                "MinCapacity": 1,
                "MaxCapacity": 4
            },
            "CreationTime": "2023-12-02T17:00:02.041000+09:00"
        }
    ]
}