This KCNA practice question tests your understanding of container orchestration. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
You have a microservices application where Service A needs to discover the IP of Service B. Both services run in the same Kubernetes cluster. Which approach is the most Kubernetes-native way for Service A to reach Service B?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the Kubernetes DNS service to resolve the Service name 'service-b'
Kubernetes has a built-in DNS service (typically CoreDNS) that automatically creates DNS records for Services. When Service A resolves the name 'service-b' (or 'service-b.<namespace>.svc.cluster.local'), the DNS returns the cluster IP of Service B's Service object, which then load-balances traffic to the healthy Pods. This is the most Kubernetes-native approach because it leverages the platform's own service discovery mechanism without external dependencies.
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.
✓
Use the Kubernetes DNS service to resolve the Service name 'service-b'
Why this is correct
Kubernetes DNS automatically creates DNS records for Services, making this the standard approach for service discovery.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use an external service registry like Consul or etcd
Why it's wrong here
While possible, this is not the most Kubernetes-native approach; Kubernetes provides built-in service discovery via DNS.
✗
Hardcode the cluster IP of Service B in the configuration of Service A
Why it's wrong here
Hardcoding is brittle and does not adapt to changes in the Service's IP.
✗
Use environment variables injected by the Kubernetes API into each pod
Why it's wrong here
While environment variables are injected, they are not updated if the Service changes, and they are less flexible than DNS-based discovery.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think environment variables (Option D) are the primary Kubernetes-native method, but the exam emphasizes DNS as the modern, recommended approach, while environment variables are a legacy fallback with limitations.
Detailed technical explanation
How to think about this question
Under the hood, CoreDNS watches the Kubernetes API for Service and EndpointSlice objects, automatically updating DNS A/AAAA records. The default search domain includes <service>.<namespace>.svc.cluster.local, so a simple 'service-b' resolves within the same namespace. A real-world scenario: if Service B is in a different namespace, the full FQDN 'service-b.other-ns.svc.cluster.local' must be used, which is a common source of misconfiguration.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Container Orchestration — This question tests Container Orchestration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use the Kubernetes DNS service to resolve the Service name 'service-b' — Kubernetes has a built-in DNS service (typically CoreDNS) that automatically creates DNS records for Services. When Service A resolves the name 'service-b' (or 'service-b.<namespace>.svc.cluster.local'), the DNS returns the cluster IP of Service B's Service object, which then load-balances traffic to the healthy Pods. This is the most Kubernetes-native approach because it leverages the platform's own service discovery mechanism without external dependencies.
What should I do if I get this KCNA 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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