Free Amazon Web Services MLA-C01 Practice Exam with Questions & Answers | Set: 5

A sudden drop in model performance after a long period of stability is a classic indicator of data drift. According to AWS ML documentation, production data distribution drift occurs when the statistical properties of incoming data change over time compared to the training dataset.

This drift can be caused by changes in user behavior, market conditions, seasonal trends, or upstream data pipelines. When drift occurs, the model’s learned patterns no longer align with real-world data, leading to degraded accuracy and other performance metrics.

Lack of training data (Option A) and overfitting (Option D) are issues that typically manifest during initial training, not after months of stable production performance. Compute constraints (Option C) may affect latency but do not usually cause sustained accuracy degradation.

AWS recommends using SageMaker Model Monitor to detect such drift and trigger retraining workflows.

Therefore, drift in the production data distribution is the most likely cause of the observed performance degradation.

When running consecutive training jobs in Amazon SageMaker, infrastructure provisioning can introduce latency, as each job typically requires the allocation and setup of compute resources. To minimize this startup time and enhance efficiency, Amazon SageMaker offers Managed Warm Pools.

Key Features of Managed Warm Pools:

Reduced Latency: Reusing existing infrastructure significantly reduces startup time for training jobs.

Configurable Retention Period: Allows retention of resources after training jobs complete, defined by the KeepAlivePeriodInSeconds parameter.

Automatic Matching: Subsequent jobs with matching configurations (e.g., instance type) can reuse retained infrastructure.

Implementation Steps:

Request Warm Pool Quota Increase: Increase the default resource quota for warm pools through AWS Service Quotas.

Configure Training Jobs:

Set KeepAlivePeriodInSeconds for the first training job to retain resources.

Ensure subsequent jobs match the retained pool's configuration to enable reuse.

Monitor Warm Pool Usage: Track warm pool status through the SageMaker console or API to confirm resource reuse.

Considerations:

Billing: Resources in warm pools are billable during the retention period.

Matching Requirements: Jobs must have consistent configurations to use warm pools effectively.

Alternative Options:

Managed Spot Training: Reduces costs by using spare capacity but doesn’t address startup latency.

SageMaker Training Compiler: Optimizes training time but not infrastructure setup.

SageMaker Distributed Data Parallelism Library: Enhances training efficiency but doesn’t reduce setup time.

By using Managed Warm Pools, the company can significantly reduce startup latency for consecutive training jobs, ensuring faster experimentation cycles with minimal operational overhead.

AWS Documentation: Managed Warm Pools

AWS Blog: Reduce ML Model Training Job Startup Time

The primary goal is to produce the most complete dataset while handling missing values and extreme outliers appropriately. Dropping samples (Option A) or columns (Option D) would reduce data completeness and potentially remove valuable information, which contradicts the requirement.

Imputation is therefore the correct approach. Between mean and median imputation, AWS ML best practices recommend using the median when features contain outliers. The mean is sensitive to extreme values and can be skewed significantly, leading to imputed values that are not representative of the typical data distribution. In contrast, the median is robust to outliers, making it a better statistical estimator for central tendency in such datasets.

Amazon SageMaker Data Wrangler supports median imputation as a built-in transformation, enabling ML engineers to handle missing values consistently across large tabular datasets without custom code. This approach preserves all rows and columns while minimizing distortion caused by extreme values, which is particularly important for neural networks that are sensitive to input distributions.

Therefore, imputing missing values with the median value provides the most complete and statistically appropriate dataset for training.

Step 1: Create a feature group.

Step 2: Ingest the records.

Step 3: Access the store to build datasets for training.

Step 1: Create a Feature Group

Why? A feature group is the foundational unit in SageMaker Feature Store, where features are defined, stored, and organized. Creating a feature group specifies the schema (name, data type) for the features and the primary keys for data identification.

How? Use the SageMaker Python SDK or AWS CLI to define the feature group by specifying its name, schema, and S3 storage location for offline access.

Step 2: Ingest the Records

Why? After creating the feature group, the raw data must be ingested into the Feature Store. This step populates the feature group with data, making it available for both real-time and offline use.

How? Use the SageMaker SDK or AWS CLI to batch-ingest historical data or stream new records into the feature group. Ensure the records conform to the feature group schema.

Step 3: Access the Store to Build Datasets for Training

Why? Once the features are stored, they can be accessed to create training datasets. These datasets combine relevant features into a single format for machine learning model training.

How? Use the SageMaker Python SDK to query the offline store or retrieve real-time features using the online store API. The offline store is typically used for batch training, while the online store is used for inference.

Order Summary:

Create a feature group.

Ingest the records.

Access the store to build datasets for training.

This process ensures the features are properly managed, ingested, and accessible for model training using Amazon SageMaker Feature Store.

Apache Parquet is a columnar storage file format optimized for complex and large datasets. It provides efficient reading and processing by accessing only the required columns, which reduces I/O and speeds up data handling. This makes it ideal for use with Amazon SageMaker Canvas, where minimizing processing time is important for training ML models. Parquet is also compatible with S3 and widely supported in data analytics and ML workflows.

Hyperband is a hyperparameter tuning strategy designed to minimize computation time by adaptively allocating resources to promising configurations and terminating underperforming ones early. It efficiently balances exploration and exploitation, making it ideal for large datasets and deep learning models where training can be computationally expensive.

This scenario clearly describes an overfitting problem. The neural network performs well on training data but fails to generalize to evaluation data. According to AWS Machine Learning and deep learning best practices, overfitting occurs when a model learns noise or overly specific patterns in the training data instead of generalizable relationships.

L1 and L2 regularization are well-established techniques to combat overfitting. They work by penalizing large weight values during optimization, effectively constraining the model’s complexity. L1 regularization encourages sparsity, while L2 regularization (weight decay) smooths the weight distribution. AWS documentation recommends regularization as a primary method for improving generalization when a model shows a large gap between training and evaluation performance.

Option B is incorrect because removing dropout layers would increase overfitting, not reduce it. Dropout is itself a regularization technique.

Option C would likely worsen overfitting, as training for more epochs allows the model to memorize the training data even further.

Option D increases model complexity, which again exacerbates overfitting rather than resolving it.

Therefore, penalizing large weights using L1 or L2 regularization is the correct solution.

Amazon SageMaker Pipelines is designed for creating, automating, and managing end-to-end ML workflows, including complex data preprocessing tasks. It supports handling large datasets and can integrate with custom steps, such as NLP transformations. By combining SageMaker Pipelines with Amazon EventBridge, the entire workflow can be triggered and automated efficiently, meeting the requirements for scalability, automation, and processing complexity.

Step 1

Upload the existing models to the same Amazon S3 bucket path.

Multi-model endpoints require all models to be stored under a single S3 prefix so SageMaker can dynamically load them on demand.

Step 2

Create a SageMaker AI model with multi-model endpoints enabled.

This creates a SageMaker model resource that uses a multi-model–capable container (for example, XGBoost, PyTorch, or TensorFlow MME-compatible containers).

Step 3

Create an endpoint configuration that references a multi-model container.

The endpoint configuration defines:

Instance type

Initial instance count

The multi-model container reference

Step 4

Deploy a real-time inference endpoint by using the endpoint configuration.

Real-time endpoints ensure low-latency inference, which is a strict customer requirement.

Step 5

Update the models to use the new endpoint ID. Pass the model IDs to the new endpoint.

Each inference request specifies a model ID so SageMaker knows which model to load from S3.

AWS Glue DataBrew provides an easy-to-use interface for preparing and transforming data, including masking or obfuscating sensitive information. It offers built-in data masking features, allowing the ML engineer to handle sensitive data securely while retaining its structure and meaning. This solution is efficient and requires minimal coding, making it ideal for ensuring sensitive data is masked before model building begins.