How can dynamodb secondary indexes be autoscaled with Cloudformation templates?

user_4024474 0
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I've seen the examples for adding autoscaling to tables with cloudformation, but other than the "Apply same settings to global secondary indexes" checkbox in the dynamodb console, I don't see a way to define this with cloudformation templates.

amazon-dynamodb amazon-web-services
2 Answers

It is possible to define the secondary index as an autoscaling target.

You need just to specify the index as the resourceId using /index/**YOUR_INDEX_NAME** as a suffix and using dynamodb:index:WriteCapacityUnits and dynamodb:index:ReadCapacityUnits as ScalableDimension.

E.g.

  SecIndexWriteCapacity:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      MaxCapacity: 1000
      MinCapacity: 15
      ResourceId: !Sub "table/${MY_MAIN_TABLE}/index/${MY_SECONDARY_INDEX_NAME}"
      RoleARN: !GetAtt ScalingRole.Arn
      ScalableDimension: dynamodb:index:WriteCapacityUnits
      ServiceNamespace: dynamodb
  SecIndexReadCapacity:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      MaxCapacity: 1000
      MinCapacity: 15
      ResourceId: !Sub "table/${MY_MAIN_TABLE}/index/MY_SECONDARY_INDEX_NAME"
      RoleARN: !GetAtt ScalingRole.Arn
      ScalableDimension: dynamodb:index:ReadCapacityUnits
      ServiceNamespace: dynamodb
  SecIndexWriteScalingPolicy:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: SecIndexWriteScalingPolicy
      PolicyType: TargetTrackingScaling
      ScalingTargetId: !Ref SecIndexWriteCapacity
      TargetTrackingScalingPolicyConfiguration:
        TargetValue: 50.0
        ScaleInCooldown: 30
        ScaleOutCooldown: 1
        PredefinedMetricSpecification:
          PredefinedMetricType: DynamoDBWriteCapacityUtilization
  SecIndexReadScalingPolicy:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: SecIndexReadScalingPolicy
      PolicyType: TargetTrackingScaling
      ScalingTargetId: !Ref SecIndexReadCapacity
      TargetTrackingScalingPolicyConfiguration:
        TargetValue: 50.0
        ScaleInCooldown: 30
        ScaleOutCooldown: 0
        PredefinedMetricSpecification:
          PredefinedMetricType: DynamoDBReadCapacityUtilization

See also https://aws.amazon.com/blogs/database/how-to-use-aws-cloudformation-to-configure-auto-scaling-for-amazon-dynamodb-tables-and-indexes/

user_4198630

Actually it is possible.

Follow the official AWS example for the DynamoDB/CloudFormation, but for each GSI you would need to create a separate ScalableTarget and a Scalable Policy. In the ScalableTarget properties use table/my-table/index/my-table-index notation for the ResourceId.

user_89040790
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