Skip to content

AWS Certified Machine Learning - Specialty (MLS-C01) - Fact Sheet

⚠️ RETIRED April 15, 2025. No longer available for new candidates. Replaced by AWS Machine Learning Engineer - Associate (MLA-C01). Material preserved as historical reference.

Quick Reference

Exam Details

  • Exam Code: MLS-C01
  • Duration: 180 minutes (3 hours)
  • Number of Questions: 65 questions
  • Passing Score: 750/1000
  • Question Format: Multiple choice, multiple response
  • Cost: $300 USD
  • Validity: 3 years
  • Prerequisites: Recommended 1-2 years hands-on ML/DL on AWS

Exam Domains

Domain % of Exam
Domain 1: Data Engineering 20%
Domain 2: Exploratory Data Analysis 24%
Domain 3: Modeling 36%
Domain 4: Machine Learning Implementation & Operations 20%

Domain 1: Data Engineering (20%)

Data Repositories for ML

Amazon S3

  • Primary data lake - Store raw, processed, and model artifacts
  • πŸ“– S3 for ML Data - Best practices for ML datasets
  • S3 Select - Query CSV/JSON/Parquet without full download
  • πŸ“– S3 Select Documentation
  • Lifecycle policies - Archive old training data to Glacier
  • Versioning - Track dataset versions over time

Amazon RDS / Aurora

  • Structured ML features - Store feature stores and metadata
  • πŸ“– Aurora ML - Invoke SageMaker directly from SQL
  • Aurora Serverless - Auto-scaling for variable ML workloads

Amazon Redshift

  • Data warehouse - Aggregate features from multiple sources
  • πŸ“– Redshift ML - CREATE MODEL SQL syntax
  • Redshift Spectrum - Query S3 data lakes directly

Amazon DynamoDB

  • Real-time feature store - Low-latency feature retrieval
  • πŸ“– DynamoDB for ML - Online feature store patterns
  • TTL - Automatically expire old features

Amazon Timestream

Data Ingestion and Transformation

AWS Glue

  • ETL service - Serverless data preparation
  • πŸ“– Glue for ML - ETL job authoring
  • Glue DataBrew - Visual data preparation
  • πŸ“– DataBrew Transformations - 250+ pre-built transformations
  • Glue Crawler - Auto-discover schema
  • Glue Data Catalog - Centralized metadata repository

Amazon EMR

  • Big data processing - Spark, Hadoop, Presto
  • πŸ“– EMR for ML - Spark MLlib on EMR
  • EMR Notebooks - Jupyter-based data exploration

AWS Data Pipeline

Amazon Kinesis

AWS Lambda

Data Formats and Optimization

File Formats

  • Parquet - Columnar, compressed, best for analytics (10x faster than CSV)
  • πŸ“– Parquet Format - Column pruning and predicate pushdown
  • ORC - Optimized Row Columnar, Hive-optimized
  • Avro - Row-based, schema evolution
  • RecordIO-Protobuf - SageMaker pipe mode format
  • πŸ“– SageMaker File Formats - Recommended formats

Data Partitioning

Data Security and Compliance

Encryption

Access Control

  • IAM policies - Least privilege access
  • S3 bucket policies - Resource-based access control
  • VPC endpoints - Private connectivity without internet
  • πŸ“– SageMaker VPC - Deploy in private subnets

Data Privacy

Domain 2: Exploratory Data Analysis (24%)

Data Visualization and Analysis

Amazon SageMaker Data Wrangler

  • Visual data prep - 300+ built-in transformations
  • πŸ“– Data Wrangler Guide - Import, transform, analyze
  • πŸ“– Data Wrangler Transformations - Encode, scale, handle missing
  • Quick Model - Train XGBoost to assess feature importance
  • Data Quality Report - Detect anomalies, outliers, duplicates
  • Target leakage detection - Identify features too correlated with target

Amazon SageMaker Canvas

Amazon QuickSight

Amazon Athena

  • Serverless SQL - Query S3 data lakes
  • πŸ“– Athena ML - USING FUNCTION for SageMaker inference

Jupyter Notebooks

  • SageMaker Studio - Integrated Jupyter environment
  • πŸ“– SageMaker Studio - Code, debug, visualize
  • SageMaker Notebook Instances - Managed Jupyter on EC2

Statistical Analysis

Descriptive Statistics

  • Central tendency - Mean, median, mode
  • Dispersion - Variance, standard deviation, IQR
  • Distribution - Skewness, kurtosis
  • Correlation - Pearson, Spearman correlation coefficients
  • πŸ“– Pandas Profiling - Automated EDA reports

Data Quality Issues

  • Missing values - Imputation strategies (mean, median, mode, forward-fill)
  • πŸ“– Handling Missing Data - Scikit-learn imputers
  • Outliers - Z-score, IQR method, isolation forest
  • Imbalanced classes - SMOTE, undersampling, class weights
  • πŸ“– Imbalanced-learn - Resampling techniques
  • Duplicates - Detect and remove duplicate records
  • Data drift - Monitor feature distributions over time

Feature Engineering

  • Numerical transformations - Log, square root, polynomial features
  • Scaling - StandardScaler, MinMaxScaler, RobustScaler
  • Encoding categorical - One-hot, ordinal, target encoding
  • πŸ“– Feature Engineering - Data Wrangler techniques
  • Binning - Convert continuous to categorical
  • Feature crosses - Interaction features (A Γ— B)
  • Time features - Extract hour, day, month, season

Dimensionality Reduction

Data Splitting Strategies

Train/Validation/Test Split

  • 70/15/15 or 80/10/10 - Typical splits
  • Stratified split - Preserve class distribution
  • Time-based split - For time-series (no random shuffle)
  • πŸ“– Scikit-learn Split

Cross-Validation

  • K-fold CV - Split into k folds, train on k-1
  • Stratified K-fold - Maintain class balance
  • Time-series CV - Walk-forward validation
  • Leave-one-out CV - For small datasets

Domain 3: Modeling (36%)

Amazon SageMaker Built-in Algorithms

Linear Models

  • Linear Learner - Linear regression, logistic regression, multiclass
  • πŸ“– Linear Learner - L1/L2 regularization, auto-tuning
  • Use cases: Regression, binary/multiclass classification

Tree-Based Models

Deep Learning

Clustering and Anomaly Detection

NLP Algorithms

  • BlazingText - Word2Vec, text classification
  • πŸ“– BlazingText - FastText implementation
  • Modes: Word2Vec (unsupervised), text classification (supervised)
  • Object2Vec - General-purpose embeddings
  • πŸ“– Object2Vec - Sentence similarity, recommendations

Recommendation Systems

Time-Series Forecasting

  • DeepAR - Probabilistic forecasting with RNNs
  • πŸ“– DeepAR Forecasting - Multiple time-series
  • Produces: Quantile predictions (P10, P50, P90)

Deep Learning Frameworks

TensorFlow

PyTorch

Apache MXNet

Hugging Face

Model Training Strategies

Training Job Types

Distributed Training

Training Input Modes

  • File mode - Download full dataset to training instance
  • Pipe mode - Stream data from S3 (faster, less disk usage)
  • πŸ“– Pipe Mode - RecordIO-Protobuf format
  • Fast File mode - S3 FUSE mount (random access)

Hyperparameter Optimization

  • SageMaker Automatic Model Tuning - Bayesian optimization
  • πŸ“– Hyperparameter Tuning - Find best hyperparameters
  • πŸ“– Tuning Strategies - Bayesian, random, grid search
  • Hyperband - Early stopping for low-performing trials
  • Warm start - Use previous tuning job results
  • Objective metrics - Maximize accuracy, minimize loss

Model Evaluation Metrics

Classification Metrics

  • Accuracy - (TP + TN) / Total
  • Precision - TP / (TP + FP) - "Of predicted positive, how many correct?"
  • Recall - TP / (TP + FN) - "Of actual positive, how many found?"
  • F1 Score - 2 Γ— (Precision Γ— Recall) / (Precision + Recall)
  • πŸ“– Classification Metrics
  • ROC-AUC - Area under ROC curve (TPR vs FPR)
  • PR-AUC - Area under precision-recall curve (better for imbalanced)
  • Confusion matrix - TP, TN, FP, FN breakdown

Regression Metrics

  • MAE (Mean Absolute Error) - Average absolute difference
  • MSE (Mean Squared Error) - Average squared difference
  • RMSE (Root Mean Squared Error) - Square root of MSE
  • RΒ² (R-squared) - Proportion of variance explained
  • πŸ“– Regression Metrics

Ranking Metrics

  • MAP (Mean Average Precision) - Quality of ranked results
  • NDCG (Normalized Discounted Cumulative Gain) - Ranking quality with position weighting

Regularization and Overfitting

Techniques to Prevent Overfitting

  • L1 regularization (Lasso) - Adds sum of absolute weights to loss
  • L2 regularization (Ridge) - Adds sum of squared weights to loss
  • Elastic Net - Combines L1 + L2
  • Dropout - Randomly drop neurons during training (neural networks)
  • Early stopping - Stop when validation loss stops improving
  • Data augmentation - Synthetic data variations (images, text)
  • Cross-validation - Robust performance estimation

Transfer Learning and Pre-trained Models

Transfer Learning

  • Use pre-trained models - ImageNet for computer vision, BERT for NLP
  • πŸ“– Transfer Learning Guide
  • Fine-tuning - Retrain last layers on your dataset
  • Feature extraction - Use pre-trained as feature extractor

AWS AI Services (Pre-trained Models)

  • Amazon Rekognition - Image and video analysis
  • πŸ“– Rekognition - Face detection, object detection, content moderation
  • Amazon Comprehend - NLP (sentiment, entities, key phrases)
  • πŸ“– Comprehend - Custom classification and entity recognition
  • Amazon Translate - Neural machine translation
  • Amazon Polly - Text-to-speech
  • Amazon Transcribe - Speech-to-text
  • πŸ“– Transcribe - Custom vocabulary, real-time
  • Amazon Textract - OCR and form extraction
  • πŸ“– Textract - Tables, forms, key-value pairs
  • Amazon Forecast - Time-series forecasting
  • πŸ“– Forecast - AutoML for forecasting
  • Amazon Personalize - Real-time recommendations
  • πŸ“– Personalize - User-item interactions
  • Amazon Lex - Conversational AI chatbots
  • Amazon Kendra - Intelligent search service

Domain 4: ML Implementation & Operations (20%)

Model Deployment

SageMaker Hosting Options

Endpoint Configuration

Deployment Strategies

  • Blue/green deployment - New endpoint, shift traffic gradually
  • πŸ“– Blue/Green Deployment - Canary, linear, all-at-once
  • Shadow testing - Send production traffic to new model without affecting users
  • A/B testing - Split traffic between model variants
  • πŸ“– A/B Testing - Production variants

Model Monitoring

Amazon SageMaker Model Monitor

Amazon CloudWatch

MLOps and CI/CD

SageMaker Pipelines

SageMaker Projects

Model Versioning

  • Model Registry - Track model lineage
  • Model packages - Bundle model artifacts, inference code
  • Approval status - Require approval before production deployment

Edge Deployment

SageMaker Edge Manager

  • Deploy to edge devices - IoT, mobile, on-premises
  • πŸ“– Edge Manager - Manage models on fleets
  • Edge Agent - Runtime for model inference on device
  • Model optimization - Compile with SageMaker Neo

SageMaker Neo

  • Model compilation - Optimize for target hardware
  • πŸ“– SageMaker Neo - Up to 2x performance
  • Supported frameworks - TensorFlow, PyTorch, MXNet, XGBoost
  • Supported devices - ARM, Intel, Nvidia, Xilinx, edge devices

AWS IoT Greengrass

Security and Compliance

IAM and Access Control

  • IAM roles - Execution role for training jobs, hosting
  • πŸ“– SageMaker IAM Roles
  • Resource policies - Control access to models, endpoints
  • Condition keys - Fine-grained access control

Network Isolation

  • VPC mode - Training and hosting in private subnets
  • πŸ“– VPC Training and Hosting - No internet access
  • VPC endpoints - Private connectivity to S3, ECR
  • Network isolation - Block all network traffic from containers

Data Protection

  • Encryption at rest - S3, EBS volumes encrypted with KMS
  • Encryption in transit - TLS 1.2 for all API calls
  • πŸ“– SageMaker Security

Compliance

  • HIPAA eligible - Healthcare workloads
  • PCI DSS - Payment card data
  • SOC, ISO, FedRAMP - Various compliance programs
  • πŸ“– SageMaker Compliance

Cost Optimization

Training Cost Optimization

  • Managed spot training - Up to 90% savings
  • Checkpointing - Resume from checkpoint if spot interrupted
  • πŸ“– Spot Training Best Practices
  • Rightsizing instances - Start small, scale up if needed

Inference Cost Optimization

  • Multi-model endpoints - Share infrastructure across models
  • Serverless inference - Pay only for compute time used
  • Auto-scaling - Scale down during low traffic
  • Batch transform - No persistent endpoint costs

Storage Cost Optimization

  • S3 lifecycle policies - Archive old data to Glacier
  • Delete intermediate data - Training outputs, checkpoints

Common Exam Scenarios

Scenario 1: Data Preparation Pipeline

Problem: Large dataset in S3, needs ETL before training Solution: - Use AWS Glue for serverless ETL - Glue Crawler discovers schema, populates Data Catalog - Glue job transforms data to Parquet with Hive partitioning - Store in S3, query with Athena for validation - πŸ“– Glue ETL Best Practices

Scenario 2: Hyperparameter Tuning at Scale

Problem: Need to find best hyperparameters for XGBoost Solution: - SageMaker Automatic Model Tuning with Bayesian optimization - Define hyperparameter ranges (max_depth: 3-10, eta: 0.01-0.3) - Specify objective metric (validation:auc) - Use managed spot training for cost savings - πŸ“– XGBoost Tuning Guide

Scenario 3: Real-time Image Classification

Problem: Deploy image classification model for low-latency inference Solution: - Use SageMaker built-in Image Classification or custom CNN - Transfer learning from ResNet-50 pre-trained on ImageNet - Deploy to real-time endpoint with GPU instance (ml.p3.2xlarge) - Enable auto-scaling based on InvocationsPerInstance - A/B testing with production variants - πŸ“– Image Classification Deployment

Scenario 4: Batch Predictions on Large Dataset

Problem: Score 1 million records without persistent endpoint Solution: - Use SageMaker Batch Transform - Input data in S3 (CSV or JSON Lines format) - Specify instance type and count for parallelization - Output predictions to S3 - No endpoint costs after job completes - πŸ“– Batch Transform Best Practices

Scenario 5: Model Monitoring and Retraining

Problem: Detect model drift and trigger retraining Solution: - SageMaker Model Monitor for data quality monitoring - Set baseline from training data - Schedule monitoring jobs (hourly, daily) - CloudWatch alarm triggers when drift detected - Lambda function triggers SageMaker training job - SageMaker Pipelines for automated retraining workflow - πŸ“– Model Monitor Drift Detection

Scenario 6: Multi-Class Imbalanced Classification

Problem: Dataset has 1000:1 class imbalance Solution: - SMOTE (Synthetic Minority Over-sampling) or undersampling - Use class weights in loss function - Evaluation metrics: F1 score, PR-AUC (not accuracy!) - Consider anomaly detection (Random Cut Forest) if extreme imbalance - πŸ“– Handling Imbalanced Data

Scenario 7: Distributed Training for Large Model

Problem: Train 10B parameter Transformer model Solution: - Use SageMaker model parallel library - Pipeline parallelism or tensor parallelism - Multi-GPU instances (ml.p4d.24xlarge with 8x A100 GPUs) - Distributed data parallel for data parallelism across nodes - πŸ“– Model Parallel Training

Scenario 8: Secure ML in VPC

Problem: Healthcare data, must stay in private network Solution: - VPC mode for training and hosting - Private subnets with no internet gateway - VPC endpoints for S3, SageMaker, ECR - KMS encryption for S3, EBS volumes - IAM roles with least privilege - πŸ“– VPC Security Configuration

Exam Tips

Key Topics to Master

  1. SageMaker algorithms - When to use each (XGBoost, Linear Learner, DeepAR, etc.)
  2. Data formats - Parquet vs CSV, RecordIO-Protobuf for pipe mode
  3. Hyperparameter tuning - Bayesian vs random, objective metrics
  4. Evaluation metrics - Precision vs recall, when to use F1 vs AUC
  5. Deployment options - Real-time vs batch vs serverless vs async
  6. Model monitoring - Data drift, model drift detection
  7. Security - VPC, encryption, IAM roles
  8. Cost optimization - Spot training, serverless inference, multi-model endpoints

Common Pitfalls

  • Confusing accuracy with F1 - Use F1 or PR-AUC for imbalanced classes
  • Not using spot training - Always consider for cost savings
  • Wrong deployment type - Batch transform for large one-time scoring, not real-time
  • Forgetting data drift - Production models need continuous monitoring
  • Not using pipe mode - Faster training for large datasets vs file mode

Calculation and Formula Questions

  • Precision = TP / (TP + FP)
  • Recall = TP / (TP + FN)
  • F1 Score = 2 Γ— (Precision Γ— Recall) / (Precision + Recall)
  • Training time estimate - Consider instance type, data size, algorithm complexity
  • Cost estimate - Instance hours Γ— instance price (don't forget spot savings)

AWS AI Services Decision Tree

  • Pre-trained model sufficient? β†’ Use AWS AI service (Rekognition, Comprehend, etc.)
  • Need custom model on tabular data? β†’ SageMaker XGBoost or Linear Learner
  • Need custom deep learning? β†’ SageMaker with TensorFlow/PyTorch
  • Need transfer learning? β†’ SageMaker built-in (Image Classification, BlazingText)
  • Need AutoML? β†’ SageMaker Autopilot or Canvas

Algorithm Selection Guide

Problem Type Best Algorithm(s) Notes
Binary classification (tabular) XGBoost, Linear Learner XGBoost usually best
Multi-class classification (tabular) XGBoost, Linear Learner
Regression XGBoost, Linear Learner
Image classification Image Classification (ResNet) Transfer learning from ImageNet
Object detection Object Detection (SSD) Bounding boxes
Text classification BlazingText Fast, scalable
Sentiment analysis BlazingText, Comprehend Comprehend for pre-trained
Time-series forecasting DeepAR, Forecast Forecast for AutoML
Anomaly detection Random Cut Forest, IP Insights RCF for time-series
Clustering K-Means Web-scale
Recommendations Factorization Machines, Personalize Personalize for pre-built
Embeddings Object2Vec, BlazingText Word2Vec

Essential Documentation

Core SageMaker Documentation

Deep Dive Topics

Hands-on Resources

Study Strategy

Week 1-2: Data Engineering and EDA

  • AWS Glue, EMR, data formats (Parquet, RecordIO)
  • SageMaker Data Wrangler, feature engineering
  • Statistical analysis, handling imbalanced data
  • Hands-on: ETL pipeline, EDA in notebooks

Week 3-5: Modeling

  • SageMaker built-in algorithms (all of them!)
  • Deep learning frameworks (TensorFlow, PyTorch)
  • Hyperparameter tuning, distributed training
  • Evaluation metrics, cross-validation
  • Hands-on: Train XGBoost, Image Classification, DeepAR

Week 6-7: ML Implementation and Operations

  • Deployment options, multi-model endpoints
  • Model monitoring, SageMaker Pipelines
  • Security (VPC, IAM, encryption)
  • Cost optimization strategies
  • Hands-on: Deploy endpoint, set up monitoring, build pipeline

Week 8: Practice Exams and Review

  • Take 3+ full-length practice exams
  • Review incorrect answers thoroughly
  • Focus on weak areas
  • Memorize key formulas and decision trees

Official AWS Training

Practice Exams

  • AWS Official Practice Exam - $40 (highly recommended)
  • Tutorials Dojo - Comprehensive practice tests
  • Whizlabs - Multiple practice exams

Books and Courses

  • AWS Certified Machine Learning Specialty MLS-C01 by Frank Kane (Udemy)
  • AWS Machine Learning Specialty 2023 by Stephane Maarek (Udemy)

Hands-on Practice

  • SageMaker Free Tier - 250 hours Studio notebooks (first 2 months)
  • SageMaker Examples - Official GitHub repository with 100+ notebooks

Good luck with your AWS Machine Learning Specialty certification! πŸš€