AWS Cloud Practitioner Exam | System Design Approach | Cheat Sheet

🌩️ Introduction: Meet Rahul, Your Cloud Explorer

Rahul is a budding cloud enthusiast who wants to build and deploy his first modern web application using Amazon Web Services (AWS). As he begins his journey, he quickly realizes that AWS offers hundreds of services — but learning them in isolation feels overwhelming.

To make things easier, Rahul decides to learn AWS through a story-based approach: at every step of building his application, he discovers a new AWS service or concept. Each table in this guide follows Rahul’s path — from compute and storage to databases, security, networking, and AI — giving you:

• A mini storyline for quick recall,

• The AWS service name and one-line purpose,

• A commonly asked CLF-C02 exam question, and

• A crisp answer for revision or interview prep.

This format makes complex cloud topics simple, visual, and practical — just like learning by building.

☁️ Part 1: Compute & Storage — “Rahul Starts Building His App”

Rahul begins his journey by setting up the foundation — compute and storage. He needs servers, security, and reliable data storage. Along the way, he learns about EC2, EBS, S3, and more — the essential building blocks that power everything else in the AWS ecosystem.

🧠 Rahul’s Cloud Journey – Compute & Storage Foundation

Storyline (Rahul’s step)	Service / Concept	1-Line Definition	Common Exam Question
Rahul wants to automate AWS setup	AWS CLI (Command Line Interface)	Tool to manage AWS services via terminal using commands.	What is the AWS CLI used for?
Rahul writes code to access AWS programmatically	AWS SDK (Software Development Kit)	Language-specific libraries to interact with AWS from applications.	How does an application interact programmatically with AWS?
Rahul needs servers to host his app	EC2 Instance (Elastic Compute Cloud)	Virtual servers in the cloud to run applications.	Which service provides resizable compute capacity in the cloud?
Rahul wants to secure access to his EC2	Security Groups	Virtual firewalls that control inbound and outbound traffic to EC2 instances.	How does AWS control traffic to EC2 instances?
Rahul attaches storage to EC2	EBS Volumes (Elastic Block Store)	Persistent block-level storage that attaches to EC2 instances.	What type of storage is best for data that must persist after instance stop?
Rahul wants to reuse his EC2 setup	AMI (Amazon Machine Image)	A pre-configured template for launching EC2 instances.	What is an AMI used for?
Rahul needs shared storage across servers	EFS (Elastic File System)	Fully managed NFS that allows multiple EC2 instances to access shared files.	What file system can be mounted to multiple EC2 instances across AZs?
Rahul’s app runs on Windows / HPC workloads	FSx	Managed Windows and Lustre file systems for Windows and HPC workloads.	Which service provides managed Windows native or HPC file systems?
Rahul’s app must handle user traffic efficiently	Elastic Load Balancer (ELB)	Distributes incoming traffic across multiple targets to ensure availability.	How do you distribute traffic automatically across EC2s?
Rahul wants to handle peak loads automatically	Auto Scaling Group (ASG)	Automatically adjusts EC2 instances based on demand.	Which service automatically increases or decreases EC2 instances based on load?

💾 Part 2: Databases & Analytics — “Rahul Learns to Store and Analyze Data”

With his application up and running, Rahul now needs structured and unstructured data stores. He learns the difference between relational and non-relational databases, caching, data lakes, and serverless query engines. This helps him understand how AWS supports analytics from OLTP systems to OLAP warehouses.

☁️ Rahul Adds Data Storage & Migration Capabilities

Storyline (Rahul’s step)	Service / Concept	1-Line Definition	Common Exam Question
Rahul needs object storage for app data	Amazon S3 (Simple Storage Service)	Object storage for storing and retrieving data at any scale.	Which service offers object storage with 99.999999999% durability?
Rahul migrates large datasets	AWS Snowball	Physical device for transferring large data sets to AWS offline.	Which AWS service moves petabytes of data using physical devices?
Rahul connects his on-premises environment to AWS	AWS Storage Gateway	Hybrid storage service linking on-premise apps with AWS storage.	What service connects on-prem storage to S3 or EBS volumes?

Storyline (short)	Service / Concept	1-line definition	Common CLF question
Rahul needs a managed relational DB for OLTP	Relational DBs (RDS / Aurora)	Managed relational databases for transactional (OLTP) workloads.	Which AWS service provides managed relational databases?
Rahul needs analytics / data warehouse	Data Warehouse (Redshift)	Columnar, petabyte-scale data warehouse for OLAP analytics.	Which service is optimized for complex analytics on large datasets?
Rahul wants ultra-fast in-memory caching	In-memory DB (ElastiCache / Redis)	In-memory key-value / cache for sub-ms latency (Redis / Memcached).	Which service reduces DB load with in-memory caching?
Rahul needs simple key/value store	Key-Value DB (DynamoDB)	Fully managed NoSQL key-value and document database at scale.	Which AWS DB is serverless and good for single-digit ms latency at scale?
Rahul needs to query S3 with SQL	Athena	Serverless interactive query service for S3 data using SQL.	How can you run SQL queries directly against files in S3?
Rahul wants dashboards from data	QuickSight	Serverless BI service for dashboards and visualizations.	Which service builds BI dashboards from AWS data?
Rahul needs ETL for analytics	Glue	Serverless ETL and data catalog to prepare data for analytics.	Which AWS service helps transform and catalog data for analytics?
Rahul migrates databases from on-prem	Database Migration Service (DMS)	Service to migrate databases to AWS with minimal downtime.	Which service simplifies heterogeneous DB migrations to AWS?
Rahul explores graph / time series	Neptune / Timestream	Neptune = managed graph DB; Timestream = purpose-built time-series DB.	Which DB is best for graph or time-series use cases?

🐳 Part 3: Containers & Serverless — “Rahul Automates and Scales”

Rahul wants to make his application scalable and easier to deploy. He experiments with containers and serverless technologies to reduce infrastructure management. AWS services like ECS, Fargate, and Lambda allow him to focus on code, not servers — a major milestone in his cloud journey.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul packages app in a container	Docker	Container runtime / image format used to package apps.	What packages code + dependencies into containers?
Rahul runs containers on AWS	ECS (Elastic Container Service)	Managed container orchestration service for Docker on AWS.	Which AWS service orchestrates Docker containers?
Rahul wants serverless containers	Fargate	Serverless compute for containers — no EC2 to manage.	How to run containers without managing EC2 instances?
Rahul stores container images	ECR (Elastic Container Registry)	Managed container image registry (private repositories).	Where should you store container images for ECS/EKS?
Rahul wants simple VM+app bundle	Lightsail	Simplified VPS with predictable pricing for simple apps.	Which service offers simple VM instances with bundled features?
Rahul uses functions for microtasks	Lambda	Serverless functions that run code in response to events.	Which service runs code without provisioning servers?
Rahul exposes functions as APIs	API Gateway	Fully managed API front door for REST/HTTP APIs to Lambda or backends.	How do you create a managed REST API that invokes Lambda?
Rahul prefers PaaS for apps	Elastic Beanstalk	Platform service that deploys code and manages underlying infra.	What AWS service deploys apps and abstracts infra management?

🧩 Part 4: DevOps & Deployment — “Rahul Becomes a Builder”

As Rahul’s application grows, he embraces DevOps culture. He uses CodeCommit, CodeBuild, CodeDeploy, and CodePipeline to automate build-test-deploy workflows. Infrastructure as Code tools like CloudFormation and AWS CDK give him repeatable, consistent deployments.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul scripts infra as code	CloudFormation	Declarative IaC service to provision AWS resources via templates.	Which service automates provisioning of AWS infra from templates?
Rahul prefers code-first IaC	AWS CDK	Library/CLI to define cloud infra in real programming languages.	What tool lets you write CloudFormation in TypeScript/Python/Java?
Rahul uses CI repositories	CodeCommit	Fully managed Git hosting for source control.	Which AWS managed Git service stores source code?
Rahul builds & tests code	CodeBuild	Managed build service that compiles, tests, and produces artifacts.	Which service compiles source and runs tests in CI?
Rahul deploys code to servers	CodeDeploy	Automates code deployments to EC2, Lambda, on-prem.	Which AWS service automates deployments across targets?
Rahul creates pipelines	CodePipeline	Orchestrates build, test, deploy stages for continuous delivery.	Which service provides a continuous delivery pipeline?
Rahul stores packages	CodeArtifact	Managed artifact repository for packages (npm, Maven, pip).	Where to store build artifacts & package dependencies?
Rahul wants pre-built app hosting	Lightsail / Elastic Beanstalk	(Lightsail: simple stacks; Beanstalk: PaaS app management).	Which service is simplest for one-click app hosting?

📬 Part 5: Messaging & Integration — “Rahul Connects Everything”

Next, Rahul wants different components of his app to communicate efficiently. He uses SQS for message queues, SNS for notifications, and Kinesis for real-time streaming. These services help him decouple and scale the system seamlessly.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul sends a task to a queue	SQS (Simple Queue Service)	Fully managed message queue for decoupling components.	Which service decouples components via asynchronous queues?
Rahul broadcasts notifications	SNS (Simple Notification Service)	Pub/sub notifications to multiple subscribers (SMS, email, SQS, Lambda).	How to push messages to many subscribers simultaneously?
Rahul needs real-time streaming	Kinesis	Real-time data streaming for ingestion and processing.	Which service handles real-time ingestion & processing of streaming data?
Rahul needs broker compatibility	Amazon MQ	Managed message broker (ActiveMQ/RabbitMQ) for legacy apps.	What service offers managed message brokers for standard protocols?
Rahul triggers event-driven flows	EventBridge	Serverless event bus for integrating AWS services and SaaS events.	What service routes events between AWS services and custom apps?

🌍 Part 6: Networking & Edge — “Rahul Goes Global”

Now that users are joining from across the world, Rahul focuses on speed and reliability. Route 53, CloudFront, and Global Accelerator ensure fast, low-latency access. Edge services like Outposts and Local Zones bring AWS closer to end users.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul needs DNS routing	Route 53	Scalable DNS service with routing, health checks, and domain registration.	Which AWS service manages DNS and domain registration?
Rahul caches content at edges	CloudFront (CDN)	Global CDN to deliver content with low latency from edge locations.	How to speed up static content delivery globally?
Rahul speeds uploads to S3	S3 Transfer Acceleration	Uses CloudFront edge locations to accelerate S3 uploads.	Which option accelerates S3 object uploads from remote users?
Rahul needs network-level acceleration	Global Accelerator	Global traffic manager that routes to optimal regional endpoints for performance & failover.	Which service improves global app performance by directing users to optimal endpoints?
Rahul extends AWS on-prem	Outposts / Local Zones / Wavelength	Outposts = AWS hardware on-prem; Local Zones & Wavelength = low-latency edge zones.	Which services bring AWS infra closer to users/on-prem?

🔒 Part 7: Security, Identity & Compliance — “Rahul Secures His Kingdom”

As his app handles more users and data, Rahul learns about security fundamentals. Using IAM, KMS, GuardDuty, and Security Hub, he enforces least privilege, encryption, and continuous monitoring — key principles of the shared responsibility model.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul manages identities & perms	IAM (Identity & Access Management)	Core identity and access control service (users, roles, policies).	Which service manages users, roles, and permissions?
Rahul needs temporary credentials	STS (Security Token Service)	Issues temporary, limited-privilege credentials.	How do you grant short-term credentials for cross-account access?
Rahul adds user sign-in for apps	Cognito	Managed user sign-up, sign-in and access control for mobile/web apps.	Which service manages authentication for mobile/web app users?
Rahul encrypts data keys	KMS (Key Management Service)	Managed service for creating and controlling encryption keys.	Which service centrally manages encryption keys in AWS?
Rahul needs hardware-backed keys	CloudHSM	Customer-managed hardware security modules for keys.	When would you choose CloudHSM over KMS?
Rahul wants threat detection	GuardDuty / Inspector / Macie	GuardDuty = threat detection; Inspector = vulnerability assessment; Macie = data-loss detection (S3).	Which service detects anomalous account or resource behavior?
Rahul centralizes security findings	Security Hub / Detective / Firewall Manager	Security Hub = aggregated findings; Detective = investigation; Firewall Manager = centralized WAF management.	Which service centralizes security alerts across multiple AWS services?

📈 Part 8: Monitoring & Management — “Rahul Learns to Observe and Improve”

With his app live, Rahul now needs visibility. He sets up CloudWatch for metrics, CloudTrail for auditing, and X-Ray for tracing. These services help him keep the system reliable and cost-efficient while detecting issues early.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul watches metrics & logs	CloudWatch	Monitoring for metrics, logs, alarms and dashboards.	Which service collects metrics/logs and triggers alarms?
Rahul audits API calls	CloudTrail	Records AWS API calls for auditing and compliance.	Where can you find history of API activity for your account?
Rahul needs distributed tracing	X-Ray	Traces requests across distributed applications for debugging.	Which service helps debug distributed applications by tracing requests?
Rahul wants managed ops	Systems Manager	Operational center for managing instances/inventory/runbooks/patching.	Which service automates operational tasks across EC2 and on-prem servers?
Rahul seeks code-quality insights	CodeGuru	Automated code reviews and application performance recommendations.	Which service gives automated code and performance recommendations?
Rahul checks account health	AWS Health Dashboard	Personalized view of AWS service health affecting your resources.	Where do you see AWS events that affect your account resources?

🤖 Part 9: AI, ML & Analytics — “Rahul Adds Intelligence”

Rahul doesn’t stop there. He integrates AI services like Rekognition, Polly, Comprehend, and SageMaker to make his application smarter — from image recognition to personalized recommendations. AWS’s pre-built AI services help him innovate faster without deep ML expertise.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul adds image analysis	Rekognition	Image & video analysis (faces, labels, moderation).	Which service analyzes images and videos for objects and faces?
Rahul converts speech → text	Transcribe	Automatic speech-to-text service.	Which service provides automatic speech recognition?
Rahul needs TTS	Polly	Text-to-speech service producing lifelike speech.	Which service converts text into natural speech?
Rahul translates text	Translate	Neural machine translation for text across languages.	Which service translates text between languages?
Rahul builds chatbots	Lex	Service for conversational interfaces (chatbots).	Which AWS service builds conversational bots using the same tech as Alexa?
Rahul adds intelligent search	Kendra	Enterprise search powered by ML for natural language queries.	Which service provides ML-powered enterprise search?
Rahul builds ML models	SageMaker	End-to-end managed ML platform for building, training, and deploying models.	Which service is used to train and deploy ML models at scale?
Rahul personalizes recommendations	Personalize	Managed personalization and recommendation service.	Which AWS service provides personalized recommendations (like "you may also like")?
Rahul extracts text from docs	Textract	Extracts structured text/data from scanned documents.	Which service extracts text and data from documents automatically?
Rahul adds contact-center AI	Connect	Cloud contact center service with AI integrations.	Which AWS service is a cloud contact center solution?
Rahul understands text sentiment	Comprehend	NLP service for sentiment, entity recognition, language detection.	Which service finds sentiment and entities in text?

💰 Part 10: Billing & Governance — “Rahul Learns to Manage the Cloud Wisely”

Finally, Rahul explores cost management and governance. He uses the AWS Pricing Calculator, Cost Explorer, and Billing Dashboard to track spending, and learns how Service Quotas, Organizations, and Artifact maintain control and compliance as his usage grows.

Storyline	Service / Concept	1-line definition	Common CLF question
Rahul estimates costs	Pricing Calculator	Estimate AWS costs for architecture before deploying.	How to estimate monthly AWS costs ahead of time?
Rahul inspects spend	Billing Dashboard / Cost Explorer	Visualize and analyze costs and usage over time.	Which tool helps analyze historical AWS spend?
Rahul enforces quotas & controls	Service Quotas / IAM Identity Center / Organizations	Manage service limits, identity federation / SSO.	Which services help control usage caps and centralized identity?
Rahul needs compliance artifacts	Artifact	Repository for AWS compliance reports and agreements.	Where to download AWS compliance reports?

🏁 Conclusion: From Beginner to Builder

By the end of Rahul’s story, you’ve not only understood AWS services but also seen how and when to use them together. This practical, narrative-driven format transforms the Cloud Practitioner syllabus into a visual roadmap.

Whether you’re studying for AWS CLF-C02, preparing for cloud interviews, or guiding teams as a project or program manager — Rahul’s journey reminds us that learning AWS isn’t about memorizing terms; it’s about connecting ideas, one service at a time.

Resources:

AWS Cloud Practitioner Flash Cards

AWS Cloud Practitioner Exam Cheat Sheet