AWS Cloud Practitioner Course Notes

CLF-C02 cloud concepts questions usually test why cloud changes the operating model. AWS replaces large upfront purchases with pay-as-you-go consumption, gives fast access to compute and storage, and lets workloads reach users through a global infrastructure. OpEx means paying as services are consumed; CapEx means buying facilities or hardware before demand is proven.

• Calling elasticity and scalability the same thing; elasticity is about automatic adjustment with demand, while scalability is simply the ability to add capacity.

• Elasticity means capacity changes with demand; scalability means capacity can grow.

The Shared Responsibility Model is the center of CLF-C02 security. AWS is responsible for security of the cloud, including facilities, hardware, global infrastructure, and managed service infrastructure. The customer is responsible for security in the cloud, such as IAM permissions, data protection choices, guest operating system updates on EC2, network rules, and application configuration.

• Putting EC2 guest operating system patching on AWS instead of the customer under the Shared Responsibility Model.

• CloudTrail equals API activity; AWS Config equals resource configuration history.

Advanced security questions usually ask which AWS security service fits a specific control. IAM defines permissions and roles, while AWS STS provides temporary security credentials that applications, users, or federated identities can assume. Temporary credentials are preferred when access should expire instead of relying on long-term access keys.

• Choosing long-term access keys when the scenario asks for temporary credentials, which points to AWS STS.

• STS issues temporary credentials for assumed roles and federation.

Core Services is the heart of CLF-C02 because it tests service selection. The AWS Management Console is the browser interface, APIs are the programmatic service contracts, SDKs wrap APIs for programming languages, and Infrastructure as Code defines repeatable environments through templates. Regions place workloads near users or compliance boundaries, and Availability Zones give isolated locations for highly available design.

• Choosing Lambda for workloads that require operating system control, which points to EC2 instead.

• EC2 gives server control; Lambda runs serverless functions; Fargate removes server management for supported containers.

Architecture and design questions in this bank are service-integration scenarios. EventBridge is the event bus choice when one service needs to react to events from AWS services, custom applications, or SaaS sources. It fits decoupled systems where producers do not need to call consumers directly.

• Choosing CodePipeline for event routing when EventBridge is the event bus service.

• EventBridge is selected when something should happen automatically after an event.

Cost questions separate estimating, analyzing, alerting, and optimizing. AWS Pricing Calculator is used before deployment to estimate monthly cost from planned service usage. Cost Explorer analyzes historical and forecasted spend after usage exists. AWS Budgets sends alerts when cost or usage approaches configured thresholds.

• Using Pricing Calculator to analyze historical spend when Cost Explorer is the cost analysis tool.

• Pricing Calculator estimates planned cost; Cost Explorer analyzes actual and forecasted spend.