The answer is AWS Cloud Map, the correct choice because it provides DNS-based service discovery that allows containerized microservices running on Amazon ECS and EKS to dynamically find each other by name without hard-coded IP addresses. This service works by registering each microservice instance as a DNS record or via API calls, so when one service needs to communicate with another, it simply queries the DNS name and receives the current, correct endpoint—even as containers scale up, down, or restart. On the AWS Certified Cloud Practitioner CLF-C02 exam, this question tests your understanding of how AWS handles dynamic resource discovery in container environments, often appearing alongside traps like Amazon Route 53 (which is for public DNS routing, not service discovery) or Elastic Load Balancing (which distributes traffic but doesn’t register individual service instances by name). A helpful memory tip: think of Cloud Map as a “phone book for your containers”—it maps service names to live IP addresses, so your microservices can always find each other without memorizing addresses.
CLF-C02 Cloud Technology and Services Practice Question
This CLF-C02 practice question tests your understanding of cloud technology and services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company wants to ensure their containerized microservices can discover each other by name without hard-coding IP addresses. Which AWS service provides DNS-based service discovery for ECS and EKS?
Why wrong: Route 53 provides public and private DNS but doesn't automatically register and de-register container services as they scale up and down.
B
AWS Cloud Map
Cloud Map automatically registers service instances as they start and removes them as they stop, enabling dynamic DNS-based and API-based service discovery for containers.
C
Elastic Load Balancing
Why wrong: ELB provides load distribution to healthy instances but requires manual target group management — it's not a service registry for microservice discovery.
D
Amazon VPC
Why wrong: VPC provides network isolation — it doesn't include service discovery functionality for dynamically scaling containerized services.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
AWS Cloud Map
AWS Cloud Map is a cloud resource discovery service that enables microservices to dynamically discover each other by name using DNS queries or API calls. It integrates directly with Amazon ECS and EKS, allowing containers to register and resolve service endpoints without hard-coded IP addresses, making it the correct choice for DNS-based service discovery.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Amazon Route 53
Why it's wrong here
Route 53 provides public and private DNS but doesn't automatically register and de-register container services as they scale up and down.
✓
AWS Cloud Map
Why this is correct
Cloud Map automatically registers service instances as they start and removes them as they stop, enabling dynamic DNS-based and API-based service discovery for containers.
Related concept
Read the scenario before looking for a memorised answer.
✗
Elastic Load Balancing
Why it's wrong here
ELB provides load distribution to healthy instances but requires manual target group management — it's not a service registry for microservice discovery.
✗
Amazon VPC
Why it's wrong here
VPC provides network isolation — it doesn't include service discovery functionality for dynamically scaling containerized services.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Route 53's general DNS capabilities with Cloud Map's specialized service discovery, overlooking that Route 53 lacks the dynamic registration and health-check-aware instance management required for containerized microservices.
Detailed technical explanation
How to think about this question
AWS Cloud Map uses a combination of DNS (A, AAAA, SRV records) and HTTP APIs to register and discover service instances, supporting both public and private namespaces. It integrates with ECS service discovery by automatically registering tasks with the service registry, and with EKS via the Kubernetes external-dns or AWS Cloud Map controller, enabling seamless resolution of service names even as instances scale up or down. A subtle behavior is that Cloud Map supports both DNS-based and API-based discovery, where DNS queries are cached by clients (TTL as low as 60 seconds), while API calls provide real-time instance attributes like health status.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CLF-C02 question in full detail.
Cloud Technology and Services — This question tests Cloud Technology and Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: AWS Cloud Map — AWS Cloud Map is a cloud resource discovery service that enables microservices to dynamically discover each other by name using DNS queries or API calls. It integrates directly with Amazon ECS and EKS, allowing containers to register and resolve service endpoints without hard-coded IP addresses, making it the correct choice for DNS-based service discovery.
What should I do if I get this CLF-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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