CKAD Application Observability and Maintenance Practice Question
This CKAD practice question tests your understanding of application observability and maintenance. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 are a platform engineer for a large e-commerce site. The application is deployed on a Kubernetes cluster with 10 worker nodes. Recently, a new deployment 'checkout' was rolled out, and soon after, the cluster experienced network latency and intermittent connectivity issues between services. The 'checkout' pods are configured with a liveness probe that makes an HTTP request to an internal health endpoint. Upon investigation, you find that the kubelet on several nodes is consuming high CPU, and the number of iptables rules has increased significantly. You suspect that the 'checkout' deployment's configuration is causing excessive churn in the network rules. Which aspect of the deployment configuration is most likely the root cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The liveness probe is configured with a very short periodSeconds (e.g., 1) and a low failureThreshold.
A liveness probe with a very short `periodSeconds` (e.g., 1) and a low `failureThreshold` causes the kubelet to send HTTP requests to the health endpoint at a high frequency. Each probe failure triggers a pod restart, which in turn causes the kubelet to update iptables rules (e.g., for kube-proxy and network policies) to reflect the new pod IP. This rapid churn of pod restarts leads to a significant increase in iptables rules and high CPU consumption on the kubelet, as it must repeatedly reconcile the network state.
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.
✓
The liveness probe is configured with a very short periodSeconds (e.g., 1) and a low failureThreshold.
Why this is correct
Frequent probes can cause kubelet to update iptables often, especially if the probe goes through a service.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The liveness probe uses a TCP socket check instead of an HTTP GET.
Why it's wrong here
TCP socket check may be less resource-intensive than HTTP, but does not explain iptables churn.
✗
The deployment sets resource requests and limits that are too low, causing pod throttling.
Why it's wrong here
Throttling does not directly affect iptables rules.
✗
The deployment uses a large number of environment variables, causing slow container startup.
Why it's wrong here
Environment variables do not directly cause iptables churn.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may focus on the probe type (HTTP vs. TCP) or resource limits, but the root cause is the probe frequency and failure threshold causing rapid pod restarts and iptables churn, not the probe mechanism itself.
Detailed technical explanation
How to think about this question
Under the hood, each pod restart triggers the kubelet to update the node's iptables rules via kube-proxy's iptables mode, which uses `iptables-save` and `iptables-restore` to rewrite rules for service endpoints. With a `periodSeconds` of 1 and `failureThreshold` of 1, the probe fails almost immediately, causing a restart loop that can generate hundreds of iptables rule updates per minute, overwhelming the kubelet and causing network latency. In real-world scenarios, this is a common misconfiguration where operators set aggressive probe intervals without considering the cascading effect on network infrastructure.
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 CKAD 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 CKAD question in full detail.
Application Observability and Maintenance — This question tests Application Observability and Maintenance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The liveness probe is configured with a very short periodSeconds (e.g., 1) and a low failureThreshold. — A liveness probe with a very short `periodSeconds` (e.g., 1) and a low `failureThreshold` causes the kubelet to send HTTP requests to the health endpoint at a high frequency. Each probe failure triggers a pod restart, which in turn causes the kubelet to update iptables rules (e.g., for kube-proxy and network policies) to reflect the new pod IP. This rapid churn of pod restarts leads to a significant increase in iptables rules and high CPU consumption on the kubelet, as it must repeatedly reconcile the network state.
What should I do if I get this CKAD 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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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