AWS Management Console と AWS Command Line Interface (AWS CLI) を使用するほかに、Amazon 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。
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EnableDynamoDBAutoscaling.java -
DisableDynamoDBAutoscaling.java
テーブルの Application 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。
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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に対する消費された書き込みキャパシティの割合を 50% に維持することを目指します。
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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。
注記
テーブルまたはグローバルテーブルレプリカを手動で削除しても、関連するスケーラブルターゲット、スケーリングポリシー、または CloudWatch アラームは自動的には削除されません。
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.applicationautoscaling.ApplicationAutoScalingClient;
import software.amazon.awssdk.services.applicationautoscaling.model.ApplicationAutoScalingException;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalableTargetsRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalableTargetsResponse;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalingPoliciesRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalingPoliciesResponse;
import software.amazon.awssdk.services.applicationautoscaling.model.PolicyType;
import software.amazon.awssdk.services.applicationautoscaling.model.PredefinedMetricSpecification;
import software.amazon.awssdk.services.applicationautoscaling.model.PutScalingPolicyRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.RegisterScalableTargetRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.ScalingPolicy;
import software.amazon.awssdk.services.applicationautoscaling.model.ServiceNamespace;
import software.amazon.awssdk.services.applicationautoscaling.model.ScalableDimension;
import software.amazon.awssdk.services.applicationautoscaling.model.MetricType;
import software.amazon.awssdk.services.applicationautoscaling.model.TargetTrackingScalingPolicyConfiguration;
import java.util.List;
/**
* Before running this Java V2 code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class EnableDynamoDBAutoscaling {
public static void main(String[] args) {
final String usage = """
Usage:
<tableId> <roleARN> <policyName>\s
Where:
tableId - The table Id value (for example, table/Music).
roleARN - The ARN of the role that has ApplicationAutoScaling permissions.
policyName - The name of the policy to create.
""";
if (args.length != 3) {
System.out.println(usage);
System.exit(1);
}
System.out.println("This example registers an Amazon DynamoDB table, which is the resource to scale.");
String tableId = args[0];
String roleARN = args[1];
String policyName = args[2];
ServiceNamespace ns = ServiceNamespace.DYNAMODB;
ScalableDimension tableWCUs = ScalableDimension.DYNAMODB_TABLE_WRITE_CAPACITY_UNITS;
ApplicationAutoScalingClient appAutoScalingClient = ApplicationAutoScalingClient.builder()
.region(Region.US_EAST_1)
.build();
registerScalableTarget(appAutoScalingClient, tableId, roleARN, ns, tableWCUs);
verifyTarget(appAutoScalingClient, tableId, ns, tableWCUs);
configureScalingPolicy(appAutoScalingClient, tableId, ns, tableWCUs, policyName);
}
public static void registerScalableTarget(ApplicationAutoScalingClient appAutoScalingClient, String tableId, String roleARN, ServiceNamespace ns, ScalableDimension tableWCUs) {
try {
RegisterScalableTargetRequest targetRequest = RegisterScalableTargetRequest.builder()
.serviceNamespace(ns)
.scalableDimension(tableWCUs)
.resourceId(tableId)
.roleARN(roleARN)
.minCapacity(5)
.maxCapacity(10)
.build();
appAutoScalingClient.registerScalableTarget(targetRequest);
System.out.println("You have registered " + tableId);
} catch (ApplicationAutoScalingException e) {
System.err.println(e.awsErrorDetails().errorMessage());
}
}
// Verify that the target was created.
public static void verifyTarget(ApplicationAutoScalingClient appAutoScalingClient, String tableId, ServiceNamespace ns, ScalableDimension tableWCUs) {
DescribeScalableTargetsRequest dscRequest = DescribeScalableTargetsRequest.builder()
.scalableDimension(tableWCUs)
.serviceNamespace(ns)
.resourceIds(tableId)
.build();
DescribeScalableTargetsResponse response = appAutoScalingClient.describeScalableTargets(dscRequest);
System.out.println("DescribeScalableTargets result: ");
System.out.println(response);
}
// Configure a scaling policy.
public static void configureScalingPolicy(ApplicationAutoScalingClient appAutoScalingClient, String tableId, ServiceNamespace ns, ScalableDimension tableWCUs, String policyName) {
// Check if the policy exists before creating a new one.
DescribeScalingPoliciesResponse describeScalingPoliciesResponse = appAutoScalingClient.describeScalingPolicies(DescribeScalingPoliciesRequest.builder()
.serviceNamespace(ns)
.resourceId(tableId)
.scalableDimension(tableWCUs)
.build());
if (!describeScalingPoliciesResponse.scalingPolicies().isEmpty()) {
// If policies exist, consider updating an existing policy instead of creating a new one.
System.out.println("Policy already exists. Consider updating it instead.");
List<ScalingPolicy> polList = describeScalingPoliciesResponse.scalingPolicies();
for (ScalingPolicy pol : polList) {
System.out.println("Policy name:" +pol.policyName());
}
} else {
// If no policies exist, proceed with creating a new policy.
PredefinedMetricSpecification specification = PredefinedMetricSpecification.builder()
.predefinedMetricType(MetricType.DYNAMO_DB_WRITE_CAPACITY_UTILIZATION)
.build();
TargetTrackingScalingPolicyConfiguration policyConfiguration = TargetTrackingScalingPolicyConfiguration.builder()
.predefinedMetricSpecification(specification)
.targetValue(50.0)
.scaleInCooldown(60)
.scaleOutCooldown(60)
.build();
PutScalingPolicyRequest putScalingPolicyRequest = PutScalingPolicyRequest.builder()
.targetTrackingScalingPolicyConfiguration(policyConfiguration)
.serviceNamespace(ns)
.scalableDimension(tableWCUs)
.resourceId(tableId)
.policyName(policyName)
.policyType(PolicyType.TARGET_TRACKING_SCALING)
.build();
try {
appAutoScalingClient.putScalingPolicy(putScalingPolicyRequest);
System.out.println("You have successfully created a scaling policy for an Application Auto Scaling scalable target");
} catch (ApplicationAutoScalingException e) {
System.err.println("Error: " + e.awsErrorDetails().errorMessage());
}
}
}
}
テーブルの Application 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。
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.applicationautoscaling.ApplicationAutoScalingClient;
import software.amazon.awssdk.services.applicationautoscaling.model.ApplicationAutoScalingException;
import software.amazon.awssdk.services.applicationautoscaling.model.DeleteScalingPolicyRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.DeregisterScalableTargetRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalableTargetsRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalableTargetsResponse;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalingPoliciesRequest;
import software.amazon.awssdk.services.applicationautoscaling.model.DescribeScalingPoliciesResponse;
import software.amazon.awssdk.services.applicationautoscaling.model.ScalableDimension;
import software.amazon.awssdk.services.applicationautoscaling.model.ServiceNamespace;
/**
* Before running this Java V2 code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class DisableDynamoDBAutoscaling {
public static void main(String[] args) {
final String usage = """
Usage:
<tableId> <policyName>\s
Where:
tableId - The table Id value (for example, table/Music).\s
policyName - The name of the policy (for example, $Music5-scaling-policy).
""";
if (args.length != 2) {
System.out.println(usage);
System.exit(1);
}
ApplicationAutoScalingClient appAutoScalingClient = ApplicationAutoScalingClient.builder()
.region(Region.US_EAST_1)
.build();
ServiceNamespace ns = ServiceNamespace.DYNAMODB;
ScalableDimension tableWCUs = ScalableDimension.DYNAMODB_TABLE_WRITE_CAPACITY_UNITS;
String tableId = args[0];
String policyName = args[1];
deletePolicy(appAutoScalingClient, policyName, tableWCUs, ns, tableId);
verifyScalingPolicies(appAutoScalingClient, tableId, ns, tableWCUs);
deregisterScalableTarget(appAutoScalingClient, tableId, ns, tableWCUs);
verifyTarget(appAutoScalingClient, tableId, ns, tableWCUs);
}
public static void deletePolicy(ApplicationAutoScalingClient appAutoScalingClient, String policyName, ScalableDimension tableWCUs, ServiceNamespace ns, String tableId) {
try {
DeleteScalingPolicyRequest delSPRequest = DeleteScalingPolicyRequest.builder()
.policyName(policyName)
.scalableDimension(tableWCUs)
.serviceNamespace(ns)
.resourceId(tableId)
.build();
appAutoScalingClient.deleteScalingPolicy(delSPRequest);
System.out.println(policyName +" was deleted successfully.");
} catch (ApplicationAutoScalingException e) {
System.err.println(e.awsErrorDetails().errorMessage());
}
}
// Verify that the scaling policy was deleted
public static void verifyScalingPolicies(ApplicationAutoScalingClient appAutoScalingClient, String tableId, ServiceNamespace ns, ScalableDimension tableWCUs) {
DescribeScalingPoliciesRequest dscRequest = DescribeScalingPoliciesRequest.builder()
.scalableDimension(tableWCUs)
.serviceNamespace(ns)
.resourceId(tableId)
.build();
DescribeScalingPoliciesResponse response = appAutoScalingClient.describeScalingPolicies(dscRequest);
System.out.println("DescribeScalableTargets result: ");
System.out.println(response);
}
public static void deregisterScalableTarget(ApplicationAutoScalingClient appAutoScalingClient, String tableId, ServiceNamespace ns, ScalableDimension tableWCUs) {
try {
DeregisterScalableTargetRequest targetRequest = DeregisterScalableTargetRequest.builder()
.scalableDimension(tableWCUs)
.serviceNamespace(ns)
.resourceId(tableId)
.build();
appAutoScalingClient.deregisterScalableTarget(targetRequest);
System.out.println("The scalable target was deregistered.");
} catch (ApplicationAutoScalingException e) {
System.err.println(e.awsErrorDetails().errorMessage());
}
}
public static void verifyTarget(ApplicationAutoScalingClient appAutoScalingClient, String tableId, ServiceNamespace ns, ScalableDimension tableWCUs) {
DescribeScalableTargetsRequest dscRequest = DescribeScalableTargetsRequest.builder()
.scalableDimension(tableWCUs)
.serviceNamespace(ns)
.resourceIds(tableId)
.build();
DescribeScalableTargetsResponse response = appAutoScalingClient.describeScalableTargets(dscRequest);
System.out.println("DescribeScalableTargets result: ");
System.out.println(response);
}
}
