public String getClusterId() {
        return this.clusterId;
    }
<p>
Specifies the ID of a cluster. The instance group to which the automatic scaling policy is applied is within this
cluster.
</p>

@return Specifies the ID of a cluster. The instance group to which the automatic scaling policy is applied is
        within this cluster.
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/PutAutoScalingPolicyRequest.java