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AWS CloudFormation
User Guide (API Version 2010-05-15)

AWS Documentation » AWS CloudFormation » User Guide » Template Reference » AWS Resource and Property Types Reference » Application Auto Scaling Resource Types Reference » AWS::ApplicationAutoScaling::ScalableTarget

AWS::ApplicationAutoScaling::ScalableTarget

The AWS::ApplicationAutoScaling::ScalableTarget resource specifies a resource that Application Auto Scaling can scale. For more information, see the RegisterScalableTarget action in the Application Auto Scaling API Reference.

Updates to AWS::DynamoDB::Table resources that are associated with AWS::ApplicationAutoScaling::ScalableTarget resources will always result in an update failure and then an update rollback failure. The following ScalableDimension attributes cause this problem when associated with the table:

  • dynamodb:table:ReadCapacityUnits

  • dynamodb:table:WriteCapacityUnits

  • dynamodb:index:ReadCapacityUnits

  • dynamodb:index:WriteCapacityUnits

As a workaround, please deregister scalable targets before performing updates to AWS::DynamoDB::Table resources.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{
  "Type" : "AWS::ApplicationAutoScaling::ScalableTarget",
  "Properties" : {
    "MaxCapacity" : Integer,
    "MinCapacity" : Integer,
    "ResourceId" : String,
    "RoleARN" : String,
    "ScalableDimension" : String,
    "ScheduledActions" : [ ScheduledAction, ... ],
    "ServiceNamespace" : String
  }
}

YAML

Type: AWS::ApplicationAutoScaling::ScalableTarget
Properties:
  MaxCapacity: Integer
  MinCapacity: Integer
  ResourceId: String
  RoleARN: String
  ScalableDimension: String
  ScheduledActions: 
    - ScheduledAction
  ServiceNamespace: String

Properties

MaxCapacity

The maximum value that Application Auto Scaling can use to scale a target during a scaling activity.

Required: Yes

Type: Integer

Update requires: No interruption

MinCapacity

The minimum value that Application Auto Scaling can use to scale a target during a scaling activity.

Required: Yes

Type: Integer

Update requires: No interruption

ResourceId

The resource identifier to associate with this scalable target. This string consists of the resource type and unique identifier. For more information, see the ResourceId parameter for the RegisterScalableTarget action in the Application Auto Scaling API Reference, or see the ScalableTarget examples.

Required: Yes

Type: String

Update requires: Replacement

RoleARN

The Amazon Resource Name (ARN) of an AWS Identity and Access Management (IAM) role that allows Application Auto Scaling to modify your scalable target.

Required: Yes

Type: String

Update requires: No interruption

ScalableDimension

The scalable dimension that's associated with the scalable target. Specify the service namespace, resource type, and scaling property—for example, ecs:service:DesiredCount for the desired task count of an Amazon Elastic Container Service service. For valid values, see the ScalableDimension content for the ScalingPolicy data type in the Application Auto Scaling API Reference.

Required: Yes

Type: String

Update requires: Replacement

ScheduledActions

The scheduled actions for the scalable target. Duplicates aren't allowed.

Required: No

Type: List of ScheduledAction property types

Update requires: No interruption

ServiceNamespace

The namespace of the AWS service that provides the resource or custom-resource for a resource provided by your own application or service. For valid AWS service namespace values, see the RegisterScalableTarget action in the Application Auto Scaling API Reference.

Required: Yes

Type: String

Update requires: Replacement

Return Value

Ref

When the logical ID of this resource is provided to the Ref intrinsic function, Ref returns the AWS CloudFormation-generated ID of the resource, such as service/ecsStack-MyECSCluster-AB12CDE3F4GH/ecsStack-MyECSService-AB12CDE3F4GH|ecs:service:DesiredCount|ecs.

AWS CloudFormation uses the following format to generate the ID: service/resource_ID|scalable_dimension|service_namespace.

For more information about using the Ref function, see Ref.

Examples

Number of Tasks

The following example creates a scalable target for an Amazon Elastic Container Service service. Application Auto Scaling scales the number of tasks at a minimum of 1 task and a maximum of 2.

JSON

"scalableTarget" : {
  "Type" : "AWS::ApplicationAutoScaling::ScalableTarget",
  "Properties" : {
    "MaxCapacity" : 2,
    "MinCapacity" : 1,
    "ResourceId" : "service/ecsStack-MyECSCluster-AB12CDE3F4GH/ecsStack-MyECSService-AB12CDE3F4GH",
    "RoleARN" : {"Fn::GetAtt" : ["ApplicationAutoScalingRole", "Arn"] },
    "ScalableDimension" : "ecs:service:DesiredCount",
    "ServiceNamespace" : "ecs"
  }
}

YAML

scalableTarget:
  Type: AWS::ApplicationAutoScaling::ScalableTarget
  Properties:
    MaxCapacity: 2
    MinCapacity: 1
    ResourceId: service/ecsStack-MyECSCluster-AB12CDE3F4GH/ecsStack-MyECSService-AB12CDE3F4GH
    RoleARN: !GetAtt [ ApplicationAutoScalingRole, Arn ]
    ScalableDimension: ecs:service:DesiredCount
    ServiceNamespace: ecs

Using Fn::Join and Ref to Construct the ResourceId

The following example uses the Fn::Join and Ref intrinsic functions to construct the ResourceId property of the scaling target.

JSON

"SpotFleetScalingTarget": {
  "Type": "AWS::ApplicationAutoScaling::ScalableTarget",
  "Properties": {
    "MaxCapacity": 2,
    "MinCapacity": 1,
    "ResourceId": {
      "Fn::Join": [
        "/",
        [
          "spot-fleet-request",
          {
            "Ref": "ECSSpotFleet"
          }
        ]
      ]
    },
    "RoleARN": {
      "Fn::GetAtt": [
        "AutoScalingRole",
        "Arn"
      ]
    },
    "ScalableDimension": "ec2:spot-fleet-request:TargetCapacity",
    "ServiceNamespace": "ec2"
  }
}

YAML

SpotFleetScalingTarget:
  Type: AWS::ApplicationAutoScaling::ScalableTarget
  Properties:
    MaxCapacity: 2
    MinCapacity: 1
    ResourceId: !Join 
      - /
      - - spot-fleet-request
        - !Ref ECSSpotFleet
    RoleARN: !GetAtt 
      - AutoScalingRole
      - Arn
    ScalableDimension: 'ec2:spot-fleet-request:TargetCapacity'
    ServiceNamespace: ec2

Application Auto Scaling Scalable Target with an Amazon DynamoDB Table

This example sets up Application Auto Scaling for an AWS::DynamoDB::Table resource. The template defines a TargetTrackingScaling scaling policy that scales up the WriteCapacityUnits throughput for the table.

JSON

{
  "Resources": {
    "DDBTable": {
      "Type": "AWS::DynamoDB::Table",
      "Properties": {
        "AttributeDefinitions": [
          {
            "AttributeName": "ArtistId",
            "AttributeType": "S"
          },
          {
            "AttributeName": "Concert",
            "AttributeType": "S"
          },
          {
            "AttributeName": "TicketSales",
            "AttributeType": "S"
          }
        ],
        "KeySchema": [
          {
            "AttributeName": "ArtistId",
            "KeyType": "HASH"
          },
          {
            "AttributeName": "Concert",
            "KeyType": "RANGE"
          }
        ],
        "GlobalSecondaryIndexes": [
          {
            "IndexName": "GSI",
            "KeySchema": [
              {
                "AttributeName": "TicketSales",
                "KeyType": "HASH"
              }
            ],
            "Projection": {
              "ProjectionType": "KEYS_ONLY"
            },
            "ProvisionedThroughput": {
              "ReadCapacityUnits": 5,
              "WriteCapacityUnits": 5
            }
          }
        ],
        "ProvisionedThroughput": {
          "ReadCapacityUnits": 5,
          "WriteCapacityUnits": 5
        }
      }
    },
    "WriteCapacityScalableTarget": {
      "Type": "AWS::ApplicationAutoScaling::ScalableTarget",
      "Properties": {
        "MaxCapacity": 15,
        "MinCapacity": 5,
        "ResourceId": { "Fn::Join": [
          "/",
          [
            "table",
            { "Ref": "DDBTable" }
          ]
        ] },
        "RoleARN": {
          "Fn::GetAtt": ["ScalingRole", "Arn"]
        },
        "ScalableDimension": "dynamodb:table:WriteCapacityUnits",
        "ServiceNamespace": "dynamodb"
      }
    },
    "ScalingRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [
            {
              "Effect": "Allow",
              "Principal": {
                "Service": [
                  "application-autoscaling.amazonaws.com"
                ]
              },
              "Action": [
                "sts:AssumeRole"
              ]
            }
          ]
        },
        "Path": "/",
        "Policies": [
          {
            "PolicyName": "root",
            "PolicyDocument": {
              "Version": "2012-10-17",
              "Statement": [
                {
                  "Effect": "Allow",
                  "Action": [
                    "dynamodb:DescribeTable",
                    "dynamodb:UpdateTable",
                    "cloudwatch:PutMetricAlarm",
                    "cloudwatch:DescribeAlarms",
                    "cloudwatch:GetMetricStatistics",
                    "cloudwatch:SetAlarmState",
                    "cloudwatch:DeleteAlarms"
                  ],
                  "Resource": "*"
                }
              ]
            }
          }
        ]
      }
    },
    "WriteScalingPolicy": {
      "Type": "AWS::ApplicationAutoScaling::ScalingPolicy",
      "Properties": {
        "PolicyName": "WriteAutoScalingPolicy",
        "PolicyType": "TargetTrackingScaling",
        "ScalingTargetId": {
          "Ref": "WriteCapacityScalableTarget"
        },
        "TargetTrackingScalingPolicyConfiguration": {
          "TargetValue": 50.0,
          "ScaleInCooldown": 60,
          "ScaleOutCooldown": 60,
          "PredefinedMetricSpecification": {
            "PredefinedMetricType": "DynamoDBWriteCapacityUtilization"
          }
        }
      }
    }
  }
}

YAML

Resources:
  DDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      AttributeDefinitions:
        -
          AttributeName: "ArtistId"
          AttributeType: "S"
        -
          AttributeName: "Concert"
          AttributeType: "S"
        -
          AttributeName: "TicketSales"
          AttributeType: "S"
      KeySchema:
        -
          AttributeName: "ArtistId"
          KeyType: "HASH"
        -
          AttributeName: "Concert"
          KeyType: "RANGE"
      GlobalSecondaryIndexes:
        -
          IndexName: "GSI"
          KeySchema:
            -
              AttributeName: "TicketSales"
              KeyType: "HASH"
          Projection:
            ProjectionType: "KEYS_ONLY"
          ProvisionedThroughput:
            ReadCapacityUnits: 5
            WriteCapacityUnits: 5
      ProvisionedThroughput:
        ReadCapacityUnits: 5
        WriteCapacityUnits: 5
  WriteCapacityScalableTarget:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      MaxCapacity: 15
      MinCapacity: 5
      ResourceId: !Join
        - /
        - - table
          - !Ref DDBTable
      RoleARN: !GetAtt ScalingRole.Arn
      ScalableDimension: dynamodb:table:WriteCapacityUnits
      ServiceNamespace: dynamodb
  ScalingRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          -
            Effect: "Allow"
            Principal:
              Service:
                - application-autoscaling.amazonaws.com
            Action:
              - "sts:AssumeRole"
      Path: "/"
      Policies:
        -
          PolicyName: "root"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              -
                Effect: "Allow"
                Action:
                  - "dynamodb:DescribeTable"
                  - "dynamodb:UpdateTable"
                  - "cloudwatch:PutMetricAlarm"
                  - "cloudwatch:DescribeAlarms"
                  - "cloudwatch:GetMetricStatistics"
                  - "cloudwatch:SetAlarmState"
                  - "cloudwatch:DeleteAlarms"
                Resource: "*"
  WriteScalingPolicy:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: WriteAutoScalingPolicy
      PolicyType: TargetTrackingScaling
      ScalingTargetId: !Ref WriteCapacityScalableTarget
      TargetTrackingScalingPolicyConfiguration:
        TargetValue: 50.0
        ScaleInCooldown: 60
        ScaleOutCooldown: 60
        PredefinedMetricSpecification:
          PredefinedMetricType: DynamoDBWriteCapacityUtilization

Scheduled Actions

The following example creates a scheduled action for a target.

JSON

{
  "AWSTemplateFormatVersion" : "2010-09-09",
  "Description" : "Creating ECS service",
  "Parameters": {
    "AppName": {
      "Type":"String",
      "Description": "Name of app requiring ELB exposure",
      "Default": "simple-app"
    },
    "AppContainerPort": {
      "Type":"Number",
      "Description": "Container port of app requiring ELB exposure",
      "Default": "80"
    },
    "AppHostPort": {
      "Type":"Number",
      "Description": "Host port of app requiring ELB exposure",
      "Default": "80"
    }
  },
  "Resources": {
    "scalableTarget": {
      "Type": "AWS::ApplicationAutoScaling::ScalableTarget",
      "Properties": {
        "ResourceId": {
          "Fn::Join": [
            "/",
            [
              "service",
              {
                "Ref": "cluster"
              },
              {
                "Fn::GetAtt": [
                  "service",
                  "Name"
                ]
              }
            ]
          ]
        },
        "ServiceNamespace": "ecs",
        "ScalableDimension": "ecs:service:DesiredCount",
        "RoleARN": {
          "Fn::GetAtt": [
            "scalingRole",
            "Arn"
          ]
        },
        "MaxCapacity": "2",
        "MinCapacity": "1",
        "ScheduledActions": [{
          "EndTime": "2018-12-04T22:14:41.951Z",
          "ScalableTargetAction": {
            "MaxCapacity": "2",
            "MinCapacity": "1"
          },
          "ScheduledActionName": "First",
          "StartTime": "2018-11-28T22:14:41.951Z",
          "Schedule": "cron(0 0 12 ? * MON *)"
          }
        ]
      }
    },
    "scalingRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [
            {
              "Effect": "Allow",
              "Principal": {
                "Service": ["application-autoscaling.amazonaws.com"]
              },
              "Action": [
                "sts:AssumeRole"
              ]
            }
          ]
        },
        "Path": "/",
        "Policies": [
          {
            "PolicyName": "root",
            "PolicyDocument": {
              "Version": "2012-10-17",
              "Statement": [
                {
                  "Effect": "Allow",
                  "Action": "*",
                  "Resource": "*"
                }
              ]
            }
          }
        ]
      }
    },
    "cluster": {
      "Type": "AWS::ECS::Cluster"
    },
    "taskdefinition": {
      "Type": "AWS::ECS::TaskDefinition",
      "Properties": {
        "ContainerDefinitions": [
          {
            "Name": {
              "Ref": "AppName"
            },
            "MountPoints": [
              {
                "SourceVolume": "my-vol",
                "ContainerPath": "/var/www/my-vol"
              }
            ],
            "Image": "amazon/amazon-ecs-sample",
            "Cpu": "10",
            "PortMappings": [
              {
                "ContainerPort": {
                  "Ref": "AppContainerPort"
                },
                "HostPort": {
                  "Ref": "AppHostPort"
                }
              }
            ],
            "EntryPoint": [
              "/usr/sbin/apache2",
              "-D",
              "FOREGROUND"
            ],
            "Memory": "500",
            "Essential": "true"
          },
          {
            "Name": "busybox",
            "Image": "busybox",
            "Cpu": "10",
            "EntryPoint": [
              "sh",
              "-c"
            ],
            "Memory": "500",
            "Command": [
              "/bin/sh -c \"while true; do /bin/date > /var/www/my-vol/date; sleep 1; done\""
            ],
            "Essential": "false",
            "VolumesFrom": [
              {
                "SourceContainer": {
                  "Ref": "AppName"
                }
              }
            ]
          }
        ],
        "Volumes": [
          {
            "Host": {
              "SourcePath": "/var/lib/docker/vfs/dir/"
            },
            "Name": "my-vol"
          }
        ]
      }
    },
    "service": {
      "Type": "AWS::ECS::Service",
      "Properties": {
        "Cluster": {
          "Ref": "cluster"
        },
        "DesiredCount": 0,
        "TaskDefinition": {
          "Ref": "taskdefinition"
        }
      }
    }
  },
  "Outputs" : {
    "resourceId" : {
      "Description" : "ResourceId",
      "Value" : {"Fn::Join" : [ "/" , ["service", {"Ref" : "cluster"}, {"Fn::GetAtt" : ["service", "Name"]}]]}
    }
  }
}

YAML

AWSTemplateFormatVersion: 2010-09-09
Description: Creating ECS service
Parameters:
  AppName:
    Type: String
    Description: Name of app requiring ELB exposure
    Default: simple-app
  AppContainerPort:
    Type: Number
    Description: Container port of app requiring ELB exposure
    Default: '80'
  AppHostPort:
    Type: Number
    Description: Host port of app requiring ELB exposure
    Default: '80'
Resources:
  scalableTarget:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      ResourceId: !Join 
        - /
        - - service
          - !Ref cluster
          - !GetAtt service.Name
      ServiceNamespace: ecs
      ScalableDimension: 'ecs:service:DesiredCount'
      RoleARN: !GetAtt 
        - scalingRole
        - Arn
      MaxCapacity: '2'
      MinCapacity: '1'
      ScheduledActions:
        - EndTime: '2018-12-04T22:14:41.951Z'
          ScalableTargetAction:
            MaxCapacity: '2'
            MinCapacity: '1'
          ScheduledActionName: First
          StartTime: '2018-11-28T22:14:41.951Z'
          Schedule: cron(0 0 12 ? * MON *)
  scalingRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - application-autoscaling.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: root
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action: '*'
                Resource: '*'
  cluster:
    Type: AWS::ECS::Cluster
  taskdefinition:
    Type: AWS::ECS::TaskDefinition
    Properties:
      ContainerDefinitions:
        - Name: !Ref AppName
          MountPoints:
            - SourceVolume: my-vol
              ContainerPath: /var/www/my-vol
          Image: amazon/amazon-ecs-sample
          Cpu: '10'
          PortMappings:
            - ContainerPort: !Ref AppContainerPort
              HostPort: !Ref AppHostPort
          EntryPoint:
            - /usr/sbin/apache2
            - '-D'
            - FOREGROUND
          Memory: '500'
          Essential: 'true'
        - Name: busybox
          Image: busybox
          Cpu: '10'
          EntryPoint:
            - sh
            - '-c'
          Memory: '500'
          Command:
            - >-
              /bin/sh -c "while true; do /bin/date > /var/www/my-vol/date; sleep
              1; done"
          Essential: 'false'
          VolumesFrom:
            - SourceContainer: !Ref AppName
      Volumes:
        - Host:
            SourcePath: /var/lib/docker/vfs/dir/
          Name: my-vol
  service:
    Type: AWS::ECS::Service
    Properties:
      Cluster: !Ref cluster
      DesiredCount: 0
      TaskDefinition: !Ref taskdefinition
Outputs:
  resourceId:
    Description: ResourceId
    Value: !Join 
      - /
      - - service
        - !Ref cluster
        - !GetAtt service.Name