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Amazon DynamoDB
開発者ガイド (API Version 2012-08-10)

DynamoDB Auto Scaling を使用したアプリケーションのプログラミング

AWS マネジメントコンソールと AWS CLI を使用するほかに、DynamoDB Auto Scaling とやり取りするアプリケーションを作成することもできます。このセクションには、この機能をテストするために使用できる 2 つの Java プログラムが含まれています。

  • EnableDynamoDBAutoscaling.java

  • DisableDynamoDBAutoscaling.java

テーブルの アプリケーションの Auto Scaling の有効化

次のプログラムは、DynamoDB テーブル (TestTable) の Auto Scaling ポリシーをセットアップする例を示しています。プログラムの流れは次のようになります。

  • TestTable のスケーラブルなターゲットとして書き込みキャパシティーユニットを登録します。このメトリクスの範囲は 5 ~ 10 書き込みキャパシティーユニットです。

  • スケーラブルなターゲットを作成したら、次にターゲットの追跡設定を作成します。このポリシーでは、プロビジョニングされた書き込みキャパシティーに対する消費された書き込みキャパシティーの割合を 50% に維持することを目指します。

  • 次に、ターゲットの追跡設定に基づいてスケーリングポリシーを作成します。

このプログラムでは、有効な アプリケーションの Auto Scaling サービスロールの ARN を指定する必要があります (たとえば: "arn:aws:iam::122517410325:role/MyIAMAutoscalingServiceRole.) 次のプログラムの SERVICE_ROLE_ARN_GOES_HERE を実際の ARN に置き換えます。詳細については、「ステップ 1: アプリケーションの Auto Scaling のサービスロールを作成する」を参照してください。

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package com.amazonaws.codesamples.autoscaling; import com.amazonaws.services.applicationautoscaling.AWSApplicationAutoScalingClient; import com.amazonaws.services.applicationautoscaling.model.DescribeScalableTargetsRequest; import com.amazonaws.services.applicationautoscaling.model.DescribeScalableTargetsResult; import com.amazonaws.services.applicationautoscaling.model.DescribeScalingPoliciesRequest; import com.amazonaws.services.applicationautoscaling.model.DescribeScalingPoliciesResult; import com.amazonaws.services.applicationautoscaling.model.MetricType; import com.amazonaws.services.applicationautoscaling.model.PolicyType; import com.amazonaws.services.applicationautoscaling.model.PredefinedMetricSpecification; import com.amazonaws.services.applicationautoscaling.model.PutScalingPolicyRequest; import com.amazonaws.services.applicationautoscaling.model.RegisterScalableTargetRequest; import com.amazonaws.services.applicationautoscaling.model.ScalableDimension; import com.amazonaws.services.applicationautoscaling.model.ServiceNamespace; import com.amazonaws.services.applicationautoscaling.model.TargetTrackingScalingPolicyConfiguration; public class EnableDynamoDBAutoscaling { static AWSApplicationAutoScalingClient aaClient = new AWSApplicationAutoScalingClient(); public static void main(String args[]) { ServiceNamespace ns = ServiceNamespace.Dynamodb; ScalableDimension tableWCUs = ScalableDimension.DynamodbTableWriteCapacityUnits; String resourceID = "table/TestTable"; // Define the scalable target RegisterScalableTargetRequest rstRequest = new RegisterScalableTargetRequest() .withServiceNamespace(ns) .withResourceId(resourceID) .withScalableDimension(tableWCUs) .withMinCapacity(5) .withMaxCapacity(10) .withRoleARN("SERVICE_ROLE_ARN_GOES_HERE"); try { aaClient.registerScalableTarget(rstRequest); } catch (Exception e) { System.err.println("Unable to register scalable target: "); System.err.println(e.getMessage()); } // Verify that the target was created DescribeScalableTargetsRequest dscRequest = new DescribeScalableTargetsRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceIds(resourceID); try { DescribeScalableTargetsResult dsaResult = aaClient.describeScalableTargets(dscRequest); System.out.println("DescribeScalableTargets result: "); System.out.println(dsaResult); System.out.println(); } catch (Exception e) { System.err.println("Unable to describe scalable target: "); System.err.println(e.getMessage()); } System.out.println(); // Configure a scaling policy TargetTrackingScalingPolicyConfiguration targetTrackingScalingPolicyConfiguration = new TargetTrackingScalingPolicyConfiguration() .withPredefinedMetricSpecification( new PredefinedMetricSpecification() .withPredefinedMetricType(MetricType. DynamoDBWriteCapacityUtilization)) .withTargetValue(50.0) .withScaleInCooldown(60) .withScaleOutCooldown(60); // Create the scaling policy, based on your configuration PutScalingPolicyRequest pspRequest = new PutScalingPolicyRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceId(resourceID) .withPolicyName("MyScalingPolicy") .withPolicyType(PolicyType.TargetTrackingScaling) .withTargetTrackingScalingPolicyConfiguration(targetTrackingScalingPolicyConfiguration); try { aaClient.putScalingPolicy(pspRequest); } catch (Exception e) { System.err.println("Unable to put scaling policy: "); System.err.println(e.getMessage()); } // Verify that the scaling policy was created DescribeScalingPoliciesRequest dspRequest = new DescribeScalingPoliciesRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceId(resourceID); try { DescribeScalingPoliciesResult dspResult = aaClient.describeScalingPolicies(dspRequest); System.out.println("DescribeScalingPolicies result: "); System.out.println(dspResult); } catch (Exception e) { e.printStackTrace(); System.err.println("Unable to describe scaling policy: "); System.err.println(e.getMessage()); } } }

テーブルの アプリケーションの Auto Scaling の無効化

次のプログラムは、前述のプロセスを元に戻します。Auto Scaling ポリシーを削除し、スケーラブルなターゲットを登録解除します。

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package com.amazonaws.codesamples.autoscaling; import com.amazonaws.services.applicationautoscaling.AWSApplicationAutoScalingClient; import com.amazonaws.services.applicationautoscaling.model.DeleteScalingPolicyRequest; import com.amazonaws.services.applicationautoscaling.model.DeregisterScalableTargetRequest; import com.amazonaws.services.applicationautoscaling.model.DescribeScalableTargetsRequest; import com.amazonaws.services.applicationautoscaling.model.DescribeScalableTargetsResult; import com.amazonaws.services.applicationautoscaling.model.DescribeScalingPoliciesRequest; import com.amazonaws.services.applicationautoscaling.model.DescribeScalingPoliciesResult; import com.amazonaws.services.applicationautoscaling.model.ScalableDimension; import com.amazonaws.services.applicationautoscaling.model.ServiceNamespace; public class DisableDynamoDBAutoscaling { static AWSApplicationAutoScalingClient aaClient = new AWSApplicationAutoScalingClient(); public static void main(String args[]) { ServiceNamespace ns = ServiceNamespace.Dynamodb; ScalableDimension tableWCUs = ScalableDimension.DynamodbTableWriteCapacityUnits; String resourceID = "table/TestTable"; // Delete the scaling policy DeleteScalingPolicyRequest delSPRequest = new DeleteScalingPolicyRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceId(resourceID) .withPolicyName("MyScalingPolicy"); try { aaClient.deleteScalingPolicy(delSPRequest); } catch (Exception e) { System.err.println("Unable to delete scaling policy: "); System.err.println(e.getMessage()); } // Verify that the scaling policy was deleted DescribeScalingPoliciesRequest descSPRequest = new DescribeScalingPoliciesRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceId(resourceID); try { DescribeScalingPoliciesResult dspResult = aaClient.describeScalingPolicies(descSPRequest); System.out.println("DescribeScalingPolicies result: "); System.out.println(dspResult); } catch (Exception e) { e.printStackTrace(); System.err.println("Unable to describe scaling policy: "); System.err.println(e.getMessage()); } System.out.println(); // Remove the scalable target DeregisterScalableTargetRequest delSTRequest = new DeregisterScalableTargetRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceId(resourceID); try { aaClient.deregisterScalableTarget(delSTRequest); } catch (Exception e) { System.err.println("Unable to deregister scalable target: "); System.err.println(e.getMessage()); } // Verify that the scalable target was removed DescribeScalableTargetsRequest dscRequest = new DescribeScalableTargetsRequest() .withServiceNamespace(ns) .withScalableDimension(tableWCUs) .withResourceIds(resourceID); try { DescribeScalableTargetsResult dsaResult = aaClient.describeScalableTargets(dscRequest); System.out.println("DescribeScalableTargets result: "); System.out.println(dsaResult); System.out.println(); } catch (Exception e) { System.err.println("Unable to describe scalable target: "); System.err.println(e.getMessage()); } } }