The answer is that the Docker image has not been pushed to the ECR repository. This is the most likely cause because when SageMaker creates a model via CloudFormation, it references a specific ECR image URI in the `PrimaryContainer` definition; if that URI points to an image that does not exist in the repository, the model creation fails immediately with the "missing docker image" error. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this scenario tests your understanding of the deployment pipeline—specifically that CloudFormation does not automatically push or build containers; it only validates that the referenced image is accessible at the given URI. A common trap is assuming the error is due to incorrect IAM permissions or a network issue, but the error message itself explicitly points to a missing image, not an access denial. To remember this, think: "Push before you deploy—if the image isn't in ECR, CloudFormation can't see it."
MLS-C01 Modeling Practice Question
This MLS-C01 practice question tests your understanding of modeling. 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.
Network Topology
A data scientist is deploying a SageMaker model using CloudFormation. The stack creation fails with the above error. What is the MOST likely 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 Docker image has not been pushed to the ECR repository
The error indicates that SageMaker cannot find the Docker image specified in the `PrimaryContainer` of the model definition. CloudFormation creates the SageMaker model by referencing an ECR image URI; if that image has not been pushed to the specified ECR repository, the model creation fails immediately. This is the most common cause when the stack creation fails with an error about a missing or inaccessible image.
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 Docker image has not been pushed to the ECR repository
Why this is correct
The error clearly states the image does not exist in ECR.
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 IAM role does not have permissions to access ECR
Why it's wrong here
An IAM permission error would have a different message.
✗
The model name is incorrect
Why it's wrong here
The error is about the container image, not the model name.
✗
The instance type specified in the endpoint configuration is not available
Why it's wrong here
The error is about the container image, not the instance type.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse a missing image (resource not found) with an IAM permissions error, but the error message for a missing image is distinct and occurs at a different stage of the API call.
Detailed technical explanation
How to think about this question
Under the hood, SageMaker's `CreateModel` API validates the `PrimaryContainer.Image` field by attempting to resolve the ECR image URI. If the image does not exist in the repository, the API returns a `ValidationException` with a message like 'Cannot find image URI in ECR'. This check happens before any IAM permission evaluation for pulling the image, so a missing image fails regardless of IAM permissions. In real-world scenarios, this often occurs when the CI/CD pipeline builds a Docker image but fails to push it to ECR before the CloudFormation stack deployment.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
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.
Modeling — This question tests Modeling — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The Docker image has not been pushed to the ECR repository — The error indicates that SageMaker cannot find the Docker image specified in the `PrimaryContainer` of the model definition. CloudFormation creates the SageMaker model by referencing an ECR image URI; if that image has not been pushed to the specified ECR repository, the model creation fails immediately. This is the most common cause when the stack creation fails with an error about a missing or inaccessible image.
What should I do if I get this MLS-C01 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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