» Resource: aws_appautoscaling_policy

Provides an Application AutoScaling Policy resource.

» Example Usage

» DynamoDB Table Autoscaling 

resource "aws_appautoscaling_target" "dynamodb_table_read_target" {
  max_capacity       = 100
  min_capacity       = 5
  resource_id        = "table/tableName"
  role_arn           = "${data.aws_iam_role.DynamoDBAutoscaleRole.arn}"
  scalable_dimension = "dynamodb:table:ReadCapacityUnits"
  service_namespace  = "dynamodb"
}

resource "aws_appautoscaling_policy" "dynamodb_table_read_policy" {
  name               = "DynamoDBReadCapacityUtilization:${aws_appautoscaling_target.dynamodb_table_read_target.resource_id}"
  policy_type        = "TargetTrackingScaling"
  resource_id        = "${aws_appautoscaling_target.dynamodb_table_read_target.resource_id}"
  scalable_dimension = "${aws_appautoscaling_target.dynamodb_table_read_target.scalable_dimension}"
  service_namespace  = "${aws_appautoscaling_target.dynamodb_table_read_target.service_namespace}"

  target_tracking_scaling_policy_configuration {
    predefined_metric_specification {
      predefined_metric_type = "DynamoDBReadCapacityUtilization"
    }

    target_value = 70
  }
}

» ECS Service Autoscaling 

resource "aws_appautoscaling_target" "ecs_target" {
  max_capacity       = 4
  min_capacity       = 1
  resource_id        = "service/clusterName/serviceName"
  role_arn           = "${var.ecs_iam_role}"
  scalable_dimension = "ecs:service:DesiredCount"
  service_namespace  = "ecs"
}

resource "aws_appautoscaling_policy" "ecs_policy" {
  name               = "scale-down"
  policy_type        = "StepScaling"
  resource_id        = "${aws_appautoscaling_target.ecs_target.resource_id}"
  scalable_dimension = "${aws_appautoscaling_target.ecs_target.scalable_dimension}"
  service_namespace  = "${aws_appautoscaling_target.ecs_target.service_namespace}"

  step_scaling_policy_configuration {
    adjustment_type         = "ChangeInCapacity"
    cooldown                = 60
    metric_aggregation_type = "Maximum"

    step_adjustment {
      metric_interval_upper_bound = 0
      scaling_adjustment          = -1
    }
  }
}

» Preserve desired count when updating an autoscaled ECS Service 

resource "aws_ecs_service" "ecs_service" {
  name            = "serviceName"
  cluster         = "clusterName"
  task_definition = "taskDefinitionFamily:1"
  desired_count   = 2

  lifecycle {
    ignore_changes = ["desired_count"]
  }
}

» Aurora Read Replica Autoscaling 

resource "aws_appautoscaling_target" "replicas" {
  service_namespace  = "rds"
  scalable_dimension = "rds:cluster:ReadReplicaCount"
  resource_id        = "cluster:${aws_rds_cluster.example.id}"
  min_capacity       = 1
  max_capacity       = 15
}

resource "aws_appautoscaling_policy" "replicas" {
  name               = "cpu-auto-scaling"
  service_namespace  = "${aws_appautoscaling_target.replicas.service_namespace}"
  scalable_dimension = "${aws_appautoscaling_target.replicas.scalable_dimension}"
  resource_id        = "${aws_appautoscaling_target.replicas.resource_id}"
  policy_type        = "TargetTrackingScaling"

  target_tracking_scaling_policy_configuration {
    predefined_metric_specification {
      predefined_metric_type = "RDSReaderAverageCPUUtilization"
    }

    target_value       = 75
    scale_in_cooldown  = 300
    scale_out_cooldown = 300
  }
}

» Argument Reference

The following arguments are supported:

» Nested fields

» step_scaling_policy_configuration

  • adjustment_type - (Required) Specifies whether the adjustment is an absolute number or a percentage of the current capacity. Valid values are ChangeInCapacity, ExactCapacity, and PercentChangeInCapacity.
  • cooldown - (Required) The amount of time, in seconds, after a scaling activity completes and before the next scaling activity can start.
  • metric_aggregation_type - (Optional) The aggregation type for the policy's metrics. Valid values are "Minimum", "Maximum", and "Average". Without a value, AWS will treat the aggregation type as "Average".
  • min_adjustment_magnitude - (Optional) The minimum number to adjust your scalable dimension as a result of a scaling activity. If the adjustment type is PercentChangeInCapacity, the scaling policy changes the scalable dimension of the scalable target by this amount.
  • step_adjustment - (Optional) A set of adjustments that manage scaling. These have the following structure: 
resource "aws_appautoscaling_policy" "ecs_policy" {
  # ...

  step_scaling_policy_configuration {
    # insert config here

    step_adjustment {
      metric_interval_lower_bound = 1.0
      metric_interval_upper_bound = 2.0
      scaling_adjustment          = -1
    }

    step_adjustment {
      metric_interval_lower_bound = 2.0
      metric_interval_upper_bound = 3.0
      scaling_adjustment          = 1
    }
  }
}
  • metric_interval_lower_bound - (Optional) The lower bound for the difference between the alarm threshold and the CloudWatch metric. Without a value, AWS will treat this bound as negative infinity.
  • metric_interval_upper_bound - (Optional) The upper bound for the difference between the alarm threshold and the CloudWatch metric. Without a value, AWS will treat this bound as infinity. The upper bound must be greater than the lower bound.
  • scaling_adjustment - (Required) The number of members by which to scale, when the adjustment bounds are breached. A positive value scales up. A negative value scales down.

» target_tracking_scaling_policy_configuration

  • target_value - (Required) The target value for the metric.
  • disable_scale_in - (Optional) Indicates whether scale in by the target tracking policy is disabled. If the value is true, scale in is disabled and the target tracking policy won't remove capacity from the scalable resource. Otherwise, scale in is enabled and the target tracking policy can remove capacity from the scalable resource. The default value is false.
  • scale_in_cooldown - (Optional) The amount of time, in seconds, after a scale in activity completes before another scale in activity can start.
  • scale_out_cooldown - (Optional) The amount of time, in seconds, after a scale out activity completes before another scale out activity can start.
  • customized_metric_specification - (Optional) Reserved for future use. See supported fields below.
  • predefined_metric_specification - (Optional) A predefined metric. See supported fields below.

» customized_metric_specification

  • dimensions - (Optional) The dimensions of the metric.
  • metric_name - (Required) The name of the metric.
  • namespace - (Required) The namespace of the metric.
  • statistic - (Required) The statistic of the metric.
  • unit - (Optional) The unit of the metric.

» predefined_metric_specification

» Attribute Reference

  • arn - The ARN assigned by AWS to the scaling policy.
  • name - The scaling policy's name.
  • policy_type - The scaling policy's type.

» Import

Application AutoScaling Policy can be imported using the service-namespace , resource-id, scalable-dimension and policy-name separated by /.

$ terraform import aws_appautoscaling_policy.test-policy service-namespace/resource-id/scalable-dimension/policy-name