CKA Troubleshooting Practice Question
A pod is in 'ImagePullBackOff' state. Which of the following is NOT a common cause?
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
✓
The container requires more memory than the limit allows
Insufficient memory would cause OOMKilled, not ImagePullBackOff. ImagePullBackOff is caused by issues pulling the container image: wrong image name (C), nonexistent tag (B), authentication failure (A), or registry unreachable. Options A, B, and C are all common causes of ImagePullBackOff.
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 image registry requires authentication and no imagePullSecrets are configured
Why it's wrong here
A missing imagePullSecret for a private registry causes the kubelet to receive a 401 or 403 from the registry, so it cannot fetch the image manifest; this is a classic ImagePullBackOff trigger. Because the question asks for something that would NOT move a pod into ImagePullBackOff, this real cause is an incorrect choice, not the right answer.
- ✗
The image tag does not exist
Why it's wrong here
When the specified image tag is absent, the registry returns a manifest unknown error, and the kubelet transitions through ErrImagePull to ImagePullBackOff while it retries with exponential backoff. Since an unpublished or nonexistent tag is a legitimate cause of ImagePullBackOff, selecting it would be wrong.
- ✗
The image name is misspelled
Why it's wrong here
A misspelled image name causes the registry to answer with a repository-not-found or manifest-unknown error after the name is normalized, which again leads to ImagePullBackOff. This is another valid trigger, so it cannot be the correct response to a question looking for the non-cause.
- ✓
The container requires more memory than the limit allows
Why this is correct
If a container demands more memory than its limit allows, the image has already been successfully pulled and the container has started, so the failure mode is OOMKilled or an overloaded kubelet eviction, not ImagePullBackOff. ImagePullBackOff is exclusively a pre-start image acquisition failure, making this the one option that could never produce that state.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKA practice question is part of Courseiva's free CNCF certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CKA exam.