CKA Troubleshooting Practice Question
You are troubleshooting a pod that cannot start. Running 'kubectl describe pod' shows the event: 'Failed to pull image "myregistry.io/myapp:1.0": rpc error: code = Unknown desc = Error response from daemon: manifest for myregistry.io/myapp:1.0 not found'. What is the MOST likely cause?
⚠ Common exam trap
Test-takers frequently confuse 'manifest not found' with network or authentication errors, but the specific wording of the error message directly points to a missing tag in the registry, not connectivity or credentials.
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 image tag '1.0' does not exist in the registry
The error message 'manifest for myregistry.io/myapp:1.0 not found' indicates that the registry successfully received the pull request but could not locate the specific image tag '1.0'. This is a manifest lookup failure, not a connectivity or authentication issue. The most likely cause is that the tag '1.0' does not exist in the repository, either because it was never pushed or was removed.
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 registry is unreachable due to network issues
Why it's wrong here
If the registry were unreachable due to network issues, the container runtime would typically report errors like 'dial tcp: lookup registry.example.com: no such host' for DNS resolution failures, or 'connection refused' if the host is reachable but the port is closed. The 'manifest not found' error, however, clearly indicates successful communication with the registry but an inability to locate the requested image metadata, not a network connectivity problem.
- ✓
The image tag '1.0' does not exist in the registry
Why this is correct
The 'manifest not found' error explicitly indicates that the container runtime successfully contacted the image registry but could not locate the specific image manifest associated with the requested tag '1.0'. This means the registry confirmed its existence but reported that no image with that precise tag is available. This is the most direct and accurate interpretation of the given error message, signifying the tag itself is absent.
- ✗
The image registry requires authentication and the imagePullSecret is missing
Why it's wrong here
Authentication failures, such as a missing or incorrect imagePullSecret, would typically result in HTTP 401 Unauthorized or 403 Forbidden errors from the registry. These messages explicitly state that access to the resource is denied due to insufficient credentials. The 'manifest not found' error, conversely, implies successful authentication (or no authentication required for the resource) but an inability to find the requested image data.
- ✗
The image has been deleted from the registry
Why it's wrong here
While a deleted image could indeed lead to a 'manifest not found' error, the more common and precise interpretation when troubleshooting is that the specified tag '1.0' was either never pushed to the registry, was mistyped in the Pod definition, or was explicitly removed. If an image were truly deleted, the tag would effectively cease to exist, making this option a less direct cause than the tag simply not being present.
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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.