[DynamoDB.1]

DynamoDB tables should automatically scale capacity with demand

Description

A DynamoDB table should be able to scale its read and write capacity as required. Auto scaling capacity makes sure your applications do not run into throttling exceptions and is always available. This rule is COMPLIANT if a DynamoDB table has either on-demand capacity or provisioned mode with autoscaling enabled.

Details

Remediation

Use the following CloudFormation templates to adjust the scaling policy of your DynamoDB and make it compliant with DynamoDB.1

YAML Template

Resources:
  writeScaleTarget:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      ResourceId: table/TABLE_NAME
      RoleARN: !GetAtt SCALING_ARN
      ScalableDimension: dynamodb:table:WriteCapacityUnits
  
  readScaleTarget:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      ResourceId: table/TABLE_NAME
      RoleARN: !GetAtt SCALING_ARN
      ScalableDimension: dynamodb:table:ReadCapacityUnits
  
  writeScalePolicy:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: TableWriteScalingPolicy
      PolicyType: TargetTrackingScaling
      ScalingTargetId: !Ref writeScaleTarget
  
  readScalePolicy:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: TableReadScalingPolicy
      PolicyType: TargetTrackingScaling
      ScalingTargetId: !Ref readScaleTarget

JSON Template

{
  "Resources": {
    "writeScaleTarget": {
      "Type": "AWS::ApplicationAutoScaling::ScalableTarget",
      "Properties": {
        "ResourceId": "table/TABLE_NAME",
        "RoleARN": "SCALING_ARN",
        "ScalableDimension": "dynamodb:table:WriteCapacityUnits"
      }
    },

    "readScaleTarget": {
      "Type": "AWS::ApplicationAutoScaling::ScalableTarget",
      "Properties": {
        "ResourceId": "table/TABLE_NAME",
        "RoleARN": "SCALING_ARN",
        "ScalableDimension": "dynamodb:table:ReadCapacityUnits"
      }
    },

    "writeScalePolicy": {
      "Type": "AWS::ApplicationAutoScaling::ScalingPolicy",
      "Properties": {
        "PolicyName": "TableWriteScalingPolicy",
        "PolicyType": "TargetTrackingScaling",
        "ScalingTargetId": {
          "Ref": "writeScaleTarget"
        }
      }
    },

    "readScalePolicy": {
      "Type": "AWS::ApplicationAutoScaling::ScalingPolicy",
      "Properties": {
        "PolicyName": "TableReadScalingPolicy",
        "PolicyType": "TargetTrackingScaling",
        "ScalingTargetId": {
          "Ref": "readScaleTarget"
        }
      }
    }
  }
}

You will need to replace TABLE_NAME with the name of your DynamoDB table and SCALING_ARN with the ARN of your Scaling Role.

📓 Notes

• You must have created a valid DynamoDB table
• You must have created an IAM Scaling Role the includes the policy application-autoscaling.amazonaws.com to allow auto scaling.
• You must have created a Scaling Policy for the role which allows the following actions:

  
  

  • application-autoscaling:*

  • dynamodb:DescribeTable
  • dynamodb:UpdateTable
  • cloudwatch:PutMetricAlarm
  • cloudwatch:DescribeAlarms
  • cloudwatch:GetMetricStatistics
  • cloudwatch:SetAlarmState
  • cloudwatch:DeleteAlarm