DVA-C02 Troubleshooting and Optimization Practice Question
A developer is using AWS CloudFormation to deploy a stack that includes an S3 bucket and a Lambda function. The stack fails with the error 'The following resource(s) failed to create: [MyBucket]'. 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 S3 bucket name is already taken.
The S3 bucket name is already taken. S3 bucket names must be globally unique across all AWS accounts and regions, so if the requested name already exists, CloudFormation fails to create the MyBucket resource with exactly this kind of 'failed to create' error. The other options do not fit: a VPC configuration issue would typically affect resources like Lambda or EC2 networking, not S3 bucket creation; a malformed bucket policy would usually fail during policy attachment or update rather than initial bucket creation; and invalid Lambda code would cause the Lambda resource to fail, not MyBucket.
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 S3 bucket name is already taken.
Why this is correct
S3 bucket names must be globally unique across all AWS accounts and regions; if the specified BucketName property is already claimed by another account, CloudFormation's CreateBucket call fails immediately with a naming conflict, which is the most common cause of this specific error.
- ✗
The stack's VPC configuration is incorrect.
Why it's wrong here
S3 buckets are global, region-scoped resources that exist independently of any VPC — they have no VPC association or subnet placement, so a VPC misconfiguration is structurally incapable of causing an S3 resource creation failure.
- ✗
The S3 bucket policy is malformed.
Why it's wrong here
A bucket policy is an optional, separate sub-resource that is typically attached after the bucket already exists; a malformed policy document would fail at the AWS::S3::BucketPolicy resource, producing a distinct error referencing that resource, not MyBucket itself.
- ✗
The Lambda function code is invalid.
Why it's wrong here
The error explicitly names MyBucket as the failed resource; the Lambda function is a completely separate resource in the template, and CloudFormation reports failures per logical resource ID, so invalid Lambda code would surface under the Lambda resource's own failure message instead.
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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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services 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 DVA-C02 exam.