Question 646 of 997

Kubernetes Fundamentals →mediumMultiple ChoiceObjective-mapped

Deployment Replicas Troubleshooting — kubectl describe deployment Diagnostic

This KCNA practice question tests your understanding of kubernetes fundamentals. 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 developer creates a Deployment with 'replicas: 3'. After applying the manifest, only 2 pods are running. Which command would help identify why the third pod was not created?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.

A
kubectl logs deployment/my-deployment
Why wrong: Deployments do not have logs; pods do.
B
kubectl get pods -o wide
Why wrong: This shows pod status but not the reason for missing replicas.
C
kubectl get events --all-namespaces
Why wrong: This shows cluster-wide events but is less targeted.
D
kubectl describe deployment my-deployment
This command shows deployment events and status that reveal issues.

Full breakdown with real-world context →

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

kubectl describe deployment my-deployment

Option D is correct because `kubectl describe deployment my-deployment` provides a detailed status of the Deployment, including the ReplicaSet events, pod template, and any conditions (e.g., `Available`, `Progressing`) that explain why the desired 3 replicas are not met. It surfaces errors like insufficient resources, failed scheduling, or image pull failures that prevent the third pod from being created.

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.

✗
kubectl logs deployment/my-deployment
Why it's wrong here
Deployments do not have logs; pods do.
✗
kubectl get pods -o wide
Why it's wrong here
This shows pod status but not the reason for missing replicas.
✗
kubectl get events --all-namespaces
Why it's wrong here
This shows cluster-wide events but is less targeted.
✓
kubectl describe deployment my-deployment
Why this is correct
This command shows deployment events and status that reveal issues.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often choose `kubectl get events` (Option C) thinking it shows all cluster events, but they overlook that `kubectl describe deployment` already includes relevant events for that specific resource, making it the most targeted and efficient diagnostic tool for replica count discrepancies.

Trap categories for this question

Command / output trap
This shows pod status but not the reason for missing replicas.

Detailed technical explanation

How to think about this question

Under the hood, a Deployment manages a ReplicaSet, which in turn creates pods via the Kubernetes scheduler. When `replicas: 3` is set but only 2 pods appear, the Deployment controller’s status conditions (e.g., `ReplicaFailure`) and the ReplicaSet’s `Status.Replicas` field are immediately visible in `kubectl describe deployment`. A real-world scenario is a resource quota or node taint that prevents scheduling; the describe output will show events like 'FailedScheduling' or 'FailedCreate' with the exact reason, whereas other commands require multiple steps to correlate.

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.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this KCNA question test?

Kubernetes Fundamentals — This question tests Kubernetes Fundamentals — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: kubectl describe deployment my-deployment — Option D is correct because `kubectl describe deployment my-deployment` provides a detailed status of the Deployment, including the ReplicaSet events, pod template, and any conditions (e.g., `Available`, `Progressing`) that explain why the desired 3 replicas are not met. It surfaces errors like insufficient resources, failed scheduling, or image pull failures that prevent the third pod from being created.

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: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

About these practice questions

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Same concept, more angles

1 more ways this is tested on KCNA

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. A user creates a Deployment with 'replicas: 3'. After applying the manifest, only 2 pods are running. What is the most likely cause?

medium

A.The Deployment's YAML had a syntax error
✓ B.There is insufficient node capacity to schedule the third pod
C.The container image name is misspelled
D.The ReplicaSet controller is not running

Why B: The most likely cause is insufficient node capacity, as the scheduler cannot place the third pod due to resource constraints (CPU, memory, or other limits). The Deployment controller creates a ReplicaSet, which instructs the scheduler to place pods; if nodes lack sufficient allocatable resources, pods remain in Pending state. This is a common scenario when cluster resources are exhausted.

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