This KCNA practice question tests your understanding of container orchestration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Your organization runs a microservices application in a Kubernetes cluster with 5 worker nodes. Each microservice is deployed as a Deployment with 3 replicas. Recently, users report intermittent timeouts when accessing the frontend service. The frontend communicates with a backend service via ClusterIP. You check the backend pods and find that one of the three replicas is in CrashLoopBackOff. The other two backend pods are healthy. The frontend deployment has no readiness or liveness probes. You notice that the frontend's connection pool to the backend has a timeout of 5 seconds. The crashing backend pod logs show an occasional NullPointerException that causes the container to restart, but the pod becomes ready after restart within 2 seconds. However, the frontend's connection pool does not evict unhealthy connections quickly. What is the best course of action to reduce timeouts?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a readiness probe to the backend Deployment that checks the application health endpoint.
The intermittent timeouts occur because the frontend's connection pool holds stale connections to the backend pod that is in CrashLoopBackOff. Although the pod restarts and becomes ready within 2 seconds, the frontend does not detect that the old connection is broken and continues to use it until the 5-second timeout expires. Adding a readiness probe to the backend Deployment ensures that Kubernetes only sends traffic to pods that pass the health check; when the pod fails the probe, it is removed from the ClusterIP's endpoints, preventing the frontend from routing requests to it and thus eliminating the timeouts.
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.
✗
Increase the number of backend replicas to 5 to absorb the failures.
Why it's wrong here
More replicas may reduce impact but not eliminate timeouts if traffic still hits the unhealthy pod.
✓
Add a readiness probe to the backend Deployment that checks the application health endpoint.
Why this is correct
Readiness probe will remove the pod from the Service endpoints when it is not ready.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Add a liveness probe to the frontend Deployment.
Why it's wrong here
Liveness probe restarts frontend pods, which does not address backend issues.
✗
Increase the frontend connection pool timeout to 10 seconds.
Why it's wrong here
Longer timeout may reduce timeouts but does not prevent traffic to unhealthy backend.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse readiness and liveness probes, thinking a liveness probe is needed to restart the failing backend pod, but the real issue is traffic routing and connection pool management, which a readiness probe solves by removing the unhealthy pod from the service endpoints.
Detailed technical explanation
How to think about this question
A readiness probe in Kubernetes controls whether a pod is included as an endpoint in the associated Service's EndpointSlice. When the backend pod crashes and restarts, its readiness probe (if configured) would fail during the crash, causing the pod to be removed from the Service's endpoints. The frontend's connection pool, which typically resolves the ClusterIP to a list of pod IPs via DNS or the kube-proxy, would then only receive healthy pod IPs. Without a readiness probe, the kube-proxy continues to forward traffic to the crashing pod even after it restarts, because the pod's IP remains in the endpoints list until the pod's status changes to 'NotReady'—which only happens if a probe is defined.
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: Add a readiness probe to the backend Deployment that checks the application health endpoint. — The intermittent timeouts occur because the frontend's connection pool holds stale connections to the backend pod that is in CrashLoopBackOff. Although the pod restarts and becomes ready within 2 seconds, the frontend does not detect that the old connection is broken and continues to use it until the 5-second timeout expires. Adding a readiness probe to the backend Deployment ensures that Kubernetes only sends traffic to pods that pass the health check; when the pod fails the probe, it is removed from the ClusterIP's endpoints, preventing the frontend from routing requests to it and thus eliminating the timeouts.
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.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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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