MLS-C01 Practice Question: Machine Learning Implementation and Operations
A data scientist is using Amazon SageMaker to train a model with a custom Docker container. The training script reads data from an S3 bucket and writes the model artifact to an S3 bucket. The training job fails with a 'NoSuchKey' error. What is the MOST likely 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 training data path specified in the input data channel is incorrect.
The 'NoSuchKey' error indicates that the specified key (file path) does not exist within the S3 bucket, which occurs when the training data path provided in the input data channel is incorrect. Option A is wrong because, while a script compatibility issue could cause errors, it would not manifest as a 'NoSuchKey' S3 error; it would likely result in a failure during container execution. Option C is wrong because if the Docker image were not available in Amazon ECR, SageMaker would fail with an 'ImageNotFoundException' or similar ECR-related error, not a 'NoSuchKey' S3 error. Option D is wrong because insufficient S3 permissions (e.g., missing s3:GetObject) would result in an 'AccessDenied' error, not 'NoSuchKey'.
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 training script is not compatible with the Docker image.
Why it's wrong here
Script compatibility issues cause different errors.
- ✓
The training data path specified in the input data channel is incorrect.
Why this is correct
NoSuchKey means the S3 key does not exist.
- ✗
The Docker image is not available in Amazon ECR.
Why it's wrong here
Missing image causes 'RepositoryNotFoundException'.
- ✗
The SageMaker execution role does not have s3:GetObject permission.
Why it's wrong here
Insufficient permissions cause AccessDenied.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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