AWS CLF-C02 Services Cheat Sheet: What to Know for Every Major Service
The CLF-C02 tests your understanding of AWS services at a conceptual level — what each service does, when you would choose it, and how it differs from similar services. This cheat sheet covers every major service that appears on the exam with exactly what you need to know, and highlights the distinctions candidates most often get wrong.
💻 Compute
Provides resizable virtual server capacity. You choose the instance type (CPU, memory, storage), the operating system, and the configuration. You are responsible for patching the OS and managing everything above the hypervisor.
Use when: You need full control over a server environment, need to run legacy applications, or require specific OS configurations.
Runs code in response to events (HTTP requests, file uploads, database changes) without provisioning or managing servers. You pay only for actual execution time. Maximum execution time is 15 minutes.
Use when: Short-running event-driven tasks, microservices, scheduled jobs, or when you want zero server management overhead.
AWS's own container orchestration service for running Docker containers. Can run on EC2 instances (you manage the hosts) or on Fargate (AWS manages the hosts).
Managed Kubernetes control plane on AWS. Use when your team already uses Kubernetes and wants to run it without managing the control plane infrastructure.
Fargate removes the need to provision or manage EC2 instances for containers. It is a compute engine used with ECS or EKS — not a standalone service. You define your containers, Fargate runs them.
💾 Storage
Stores data as objects in buckets. Accessed via HTTP. Used for backups, static website hosting, data lakes, media storage. Multiple storage classes at different cost/retrieval tradeoffs.
Key storage classes: Standard (frequent access), Standard-IA (infrequent but fast retrieval), Intelligent-Tiering (auto-moves between tiers), Glacier Instant Retrieval (archive, millisecond retrieval), Glacier Flexible Retrieval (archive, minutes to hours).
Provides block-level storage volumes that attach to EC2 instances like a physical hard drive. Persists independently of the EC2 instance lifecycle. Can only be attached to one EC2 instance at a time (standard volumes).
Provides a scalable, shared file system that multiple EC2 instances can access simultaneously via NFS. Grows and shrinks automatically as you add/remove files.
A physical rugged device AWS ships to you, you load your data onto it, then ship it back to AWS for import into S3. Used when internet transfer of large datasets is too slow, too expensive, or impractical due to bandwidth constraints.
🗄️ Databases
Managed service for relational databases. Supports MySQL, PostgreSQL, MariaDB, Oracle, SQL Server, and Aurora. AWS manages the OS, database engine patching, backups, and hardware.
Serverless NoSQL key-value and document database. No servers to manage, scales automatically, consistent single-digit millisecond response times at any scale. Not suitable for complex SQL joins or transactions across many tables.
AWS's own relational database engine, available through RDS. Up to 5x faster than standard MySQL, up to 3x faster than standard PostgreSQL. Automatically replicates across multiple Availability Zones.
Managed data warehouse optimised for complex analytical queries (OLAP) against large datasets. Not designed for OLTP (frequent small transactions like those in operational applications).
In-memory data store for sub-millisecond response times. Used to cache frequently accessed database query results, session data, and computed values. Not a primary database — data is not persisted after restart (Memcached) or optionally persisted (Redis).
🌐 Networking
Lets you provision a logically isolated section of the AWS cloud with your own IP address ranges, subnets, route tables, internet gateways, and security controls. Every AWS account comes with a default VPC.
Caches content at over 400 edge locations globally, serving users from the location closest to them. Reduces latency for static assets (images, videos, scripts) and can also cache dynamic content. Integrates with S3, EC2, and ELB as origin sources.
Provides DNS resolution, domain registration, and health checking. Named after port 53, the standard DNS port. Can route traffic based on latency, geography, health, and weighted routing policies.
A dedicated physical network connection between your data centre and AWS — bypasses the public internet. Provides lower latency, more consistent network performance, and can reduce data transfer costs for high-volume workloads.
🔒 Security
Continuously analyses CloudTrail logs, VPC Flow Logs, and DNS logs to detect threats like compromised credentials, unusual API activity, and cryptomining. Generates findings that appear in Security Hub.
Automatically scans workloads for software vulnerabilities and unintended network exposure. Covers EC2 instances, container images in ECR, and Lambda functions. Not the same as behavioural threat detection.
Records every API call made in your AWS account — who did what, when, and from where. Delivers logs to S3. Essential for security auditing, compliance, and incident investigation.
Shield Standard: Automatically enabled for all AWS customers at no extra cost. Protects against common layer 3 and 4 DDoS attacks.
Shield Advanced: Paid add-on with enhanced protection, real-time metrics, DDoS cost protection, and access to the AWS DDoS Response Team.
💰 Billing and Cost Management
Interactive tool for visualising and analysing your AWS spending and usage patterns over time. Filter by service, account, region, and tag. Shows trends and can generate Reserved Instance and Savings Plan recommendations.
Creates custom budgets and sends alerts via email or SNS when actual or forecasted costs exceed thresholds. Can alert on cost, usage, Reserved Instance coverage, or Savings Plan coverage.
Inspects your AWS environment across five categories: cost optimisation, security, fault tolerance, performance, and service limits. Full checks require Business or Enterprise support plans.
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