CLF-C02 - Cloud Technology and Services (34% of the exam) - Section 3.4

Identify AWS compute services, recognising appropriate uses of Amazon EC2 instance types, auto scaling for elasticity and the purpose of load balancers.

Identify the AWS compute services relevant to common workloads, matching EC2 instance families - such as compute-optimised, memory-optimised, and general-purpose - to their intended use cases. Recognise that Auto Scaling adjusts capacity to match demand for elasticity, and that Elastic Load Balancing distributes incoming traffic across healthy targets.

Amazon EC2EC2 instance typesAuto scalingElastic Load Balancing

Practice question for this objective

Free sampleCloud Technology and Servicesmedium

An engineer combines Elastic Load Balancing with Amazon EC2 Auto Scaling for a fluctuating web application. Which statement best describes how these two services work together?

AThe load balancer decides how many instances to run, and Auto Scaling caches static content close to users at edge locations worldwide
BThe load balancer stores the application data on durable volumes, and Auto Scaling encrypts every request before it reaches an instance
CAuto Scaling provides the private network for the instances, and the load balancer resolves the application domain name to instance addresses
DAuto Scaling adjusts the number of instances with demand, and the load balancer spreads incoming traffic across the healthy instances Correct

Auto Scaling changes how many EC2 instances run with demand while Elastic Load Balancing spreads traffic across the healthy ones. The two services are complementary: Auto Scaling launches or terminates instances so the fleet matches demand, and Elastic Load Balancing distributes incoming requests across the current set of healthy instances, so the application stays responsive as capacity changes.

Why A is wrong: Auto Scaling sets the instance count rather than caching content, so this swaps the two roles and adds a caching task neither service performs here.

Why B is wrong: Load balancers do not store application data and Auto Scaling does not encrypt requests, so this misstates the purpose of both services.

Why C is wrong: A VPC provides the network and Route 53 resolves domain names, so neither described task belongs to Auto Scaling or the load balancer.

Why D is correct: Auto Scaling changes how many instances run as demand varies, while the load balancer distributes requests across whichever healthy instances exist.

See more CLF-C02 practice questions, answers explained.

Exam traps in Cloud Technology and Services

Answers that look right on this material and are not. Each one is a distractor from a different question in the CLF-C02 bank for this domain.

Amazon Route 53, a managed Domain Name System service that resolves a domain name to the network addresses of the resources behind it
Why it is wrong: Route 53 resolves domain names to addresses, but it does not distribute individual requests evenly across a pool of healthy instances.
It distributes each incoming web request evenly across the healthy instances in the running fleet.
Why it is wrong: Spreading requests across instances is the job of Elastic Load Balancing, not Amazon EC2 Auto Scaling, so this outcome is wrong here.
Amazon Elastic Block Store, which provides durable block storage volumes that attach to instances and persist independently of their lifecycle
Why it is wrong: Amazon EBS supplies persistent disk volumes for instances, so it does not change how many instances run as the traffic level varies.

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