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.
A team deploys a microservice that requires sticky sessions. The service runs on Kubernetes with multiple replicas. Which Kubernetes resource should be used to ensure requests from a client are consistently routed to the same pod?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Service with sessionAffinity: ClientIP
Option B is correct because setting `sessionAffinity: ClientIP` on a Kubernetes Service ensures that all requests from the same client IP are routed to the same Pod. This is the standard Kubernetes mechanism for implementing sticky sessions without requiring changes to the application or ingress layer.
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.
✗
Headless Service
Why it's wrong here
Headless services are for pod discovery, not load balancing with stickiness.
✓
Service with sessionAffinity: ClientIP
Why this is correct
This configuration ensures requests from the same client IP go to the same pod.
Related concept
Read the scenario before looking for a memorised answer.
✗
Ingress with default settings
Why it's wrong here
Ingress without session affinity annotation does not maintain stickiness.
✗
Deployment with hostNetwork: true
Why it's wrong here
hostNetwork does not provide session affinity.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that Ingress or Headless Services can handle session affinity by default, but only a Service with `sessionAffinity: ClientIP` provides this at the Kubernetes networking layer without additional configuration.
Detailed technical explanation
How to think about this question
Under the hood, `sessionAffinity: ClientIP` works by hashing the client IP and using that hash to select a backend Pod, with a configurable `sessionAffinityConfig.clientIP.timeoutSeconds` (default 10800 seconds) to control how long the affinity persists. This is implemented in kube-proxy's iptables or IPVS mode, where a dedicated chain ensures consistent routing. A real-world scenario is a stateful web application that stores session data in-memory on the Pod, where losing affinity would cause session errors; however, for production, external session stores (e.g., Redis) are recommended to avoid Pod failure issues.
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 practitioner preparing for the KCNA exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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: Service with sessionAffinity: ClientIP — Option B is correct because setting `sessionAffinity: ClientIP` on a Kubernetes Service ensures that all requests from the same client IP are routed to the same Pod. This is the standard Kubernetes mechanism for implementing sticky sessions without requiring changes to the application or ingress layer.
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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