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Zusätzlich zur Verwendung von AWS Management Console und AWS Command Line Interface (AWS CLI) können Sie Anwendungen schreiben, die mit Amazon DynamoDB Auto Scaling interagieren. Dieser Abschnitt enthält zwei Java-Programme, die Sie verwenden können, um diese Funktionalität zu testen:
-
EnableDynamoDBAutoscaling.java -
DisableDynamoDBAutoscaling.java
Aktivieren von Application Auto Scaling für eine Tabelle
Das folgende Programm zeigt ein Beispiel für die Einrichtung einer Auto-Scaling-Richtlinie für eine DynamoDB-Tabelle (TestTable). Es fährt wie folgt fort:
-
Das Programm registriert Schreibkapazitätseinheiten als skalierbares Ziel für
TestTable. Der Bereich für diese Metrik liegt zwischen 5 und 10 Schreibkapazitätseinheiten. -
Nachdem das skalierbare Ziel erstellt wird, erstellt das Programm eine Ziel-Tracking-Konfiguration. Die Richtlinie versucht ein 50 %-Zielverhältnis zwischen verbrauchter und bereitgestellter Schreibkapazität beizubehalten.
-
Das Programm erstellt dann die Skalierungsrichtlinie, basierend auf der Ziel-Tracking-Konfiguration.
Anmerkung
Wenn Sie eine Tabelle oder ein globales Tabellenreplikat manuell entfernen, entfernen Sie nicht automatisch alle zugehörigen skalierbaren Ziele, Skalierungsrichtlinien oder Alarme. CloudWatch
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());
}
}
}
}
Deaktivieren der Application Auto Scaling für eine Tabelle
Das folgende Programm macht den vorherigen Prozess rückgängig. Es entfernt die Auto Scaling-Richtlinie und hebt die Registrierung des skalierbaren Ziels auf.
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);
}
}
