Além de usar o AWS Management Console e a AWS Command Line Interface (AWS CLI), você pode escrever aplicações que interagem com o Auto Scaling do Amazon DynamoDB. Esta seção contém dois programas Java que podem ser usados para testar essa funcionalidade:
-
EnableDynamoDBAutoscaling.java -
DisableDynamoDBAutoscaling.java
Habilitação do Application Auto Scaling para uma tabela
O programa a seguir mostra um exemplo de configuração de uma política de Auto Scaling para uma tabela do DynamoDB (TestTable). Ele procede da seguinte maneira:
-
O programa registra unidades de capacidade de gravação como um destino dimensionável para a
TestTable. O intervalo dessa métrica é entre 5 e 10 unidades de capacidade de gravação. -
Depois que o destino escalável é criado, o programa cria uma configuração de rastreamento de destino. A política procura manter uma taxa de destino de 50% entre a capacidade de gravação consumida e a capacidade de gravação provisionada.
-
Em seguida, o programa cria a política de escalabilidade com base na configuração de rastreamento de destino.
nota
Ao remover manualmente uma tabela ou uma réplica de tabela global, você não remove automaticamente os destinos escaláveis associados, políticas de escalabilidade nem alarmes do 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());
}
}
}
}
Desabilitar o Application Auto Scaling para uma tabela
O programa a seguir inverte o processo anterior. Ele remove a política de Auto Scaling e cancela o registro do destino dimensionável.
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);
}
}
