Hello everyone, I tried to create a app scaling policy for RDS cluster but I’m getting the below error message. I confirmed with AWS doc that all the given params are correct and supported but still i’m facing this issue.

creating Application AutoScaling Target: ValidationException: Unsupported service namespace, resource type or scalable dimension

Did anyone face this kinda issue or any idea on this? Please help me with this. Thanks The script is here,

// RDS Auto Scaling Policy based on Memory Utilization
export function appMemoryScalingPolicy(rdsCpuScalingArgs: any) {
    const {
      clusterId,
      minCapacity = 1,
      maxCapacity = 2,
      targetValue = 70,
      scaleInCooldown = 300,
      scaleOutCooldown = 300,
      disableScaleIn = false,
    } = rdsCpuScalingArgs;
    const scalingTarget = new aws.appautoscaling.Target("rdsCpuScalingTarget", {
      serviceNamespace: "rds",
      scalableDimension: "rds:cluster:ReadReplicaCount",
      resourceId: `cluster:${clusterId}`,
      minCapacity: minCapacity,
      maxCapacity: maxCapacity,
    });
    return new aws.appautoscaling.Policy("rdsCpuScalingPolicy", {
      serviceNamespace: scalingTarget.serviceNamespace,
      scalableDimension: scalingTarget.scalableDimension,
      resourceId: scalingTarget.resourceId,
      policyType: "TargetTrackingScaling",
      targetTrackingScalingPolicyConfiguration: {
        customizedMetricSpecification: {
          metricName: "FreeableMemory",
          namespace: "AWS/RDS",
          statistic: "Average",
          unit: "Bytes"
        },
        targetValue: targetValue,
        scaleInCooldown: scaleInCooldown,
        scaleOutCooldown: scaleOutCooldown,
        disableScaleIn: disableScaleIn,
      },
    });
  }

I haven’t used autoscaling with RDS, but the syntax looks ok to me—it matches an ECS autoscaling target in my codebase I can see that the doco explicitly says it’s supported for Aurora for MySQL and Aurora for Postgres: https://docs.aws.amazon.com/autoscaling/application/APIReference/API_RegisterScalableTarget.html#autoscaling-RegisterScal[…]equest-ScalableDimension I don’t suppose you’re trying to use a database engine? Or possibly a non-Aurora (plain RDS) cluster?

I actually tried for both aurora and non aurora postgresql clusters and I got the same error for both.