AWS DVA-C02 Drill: AWS SAM Deployment - Defining Serverless Infrastructure Correctly

Jeff’s Note

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Unlike generic exam dumps, ADH analyzes this scenario through the lens of a Real-World Lead Developer.

For DVA-C02 candidates, the confusion often lies in how to properly integrate AWS SAM resource types within CloudFormation templates. In production, this is about knowing exactly where and how to include the AWS SAM Transform declaration so that the serverless resources are correctly interpreted and deployed. Let’s drill down.

The Certification Drill (Simulated Question)

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Scenario

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A digital startup named NexaApps is transitioning several new microservices to a fully serverless architecture. Their development team wants to use AWS Serverless Application Model (AWS SAM) to build and deploy this infrastructure. All infrastructure must be deployed via AWS CloudFormation templates, and the team wants to ensure they follow AWS best practices for defining serverless resources.

The Requirement:

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What is the correct way for the NexaApps development team to author the CloudFormation templates to meet these requirements?

The Options

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• A) Add a Resources section to the CloudFormation template containing resources of type AWS::Lambda::Function.
• B) Add a Mappings section to the CloudFormation template containing resources of types AWS::Serverless::Function and AWS::Serverless::Api.
• C) Add a Transform section to the CloudFormation template. Use AWS SAM syntax within the template to define serverless resources.
• D) Add a Parameters section to the CloudFormation template that specifies the AWS SAM Globals section.

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Correct Answer

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C

Quick Insight: The Developer Imperative

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AWS SAM uses a CloudFormation Transform declaration at the top of the template that enables syntactic sugar — like AWS::Serverless::Function — which CloudFormation alone doesn’t natively understand. Without this, only native CloudFormation resource types (like AWS::Lambda::Function) can be used directly. Understanding the Transform section is critical for leveraging SAM’s simplified syntax in your deployment templates.

Content Locked: The Expert Analysis

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You’ve identified the answer. But do you know the implementation details that separate a Junior from a Senior?

The Expert’s Analysis

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Correct Answer

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Option C

The Winning Logic

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Option C is correct because AWS SAM templates must declare a Transform section at the top of the CloudFormation template to indicate that the template uses the AWS::Serverless transform. This enables the use of SAM-specific resource types such as AWS::Serverless::Function and AWS::Serverless::Api, which provide simplified syntax for defining Lambda functions, APIs, and related serverless resources.

Without the Transform declaration, CloudFormation treats the template as a standard stack and will not recognize SAM resource types, resulting in deployment failures. Thus, the presence of:

Transform: AWS::Serverless-2016-10-31

is mandatory to leverage the SAM syntax. This facilitates easier development, reduced boilerplate, and better integration of serverless components with CloudFormation stacks.

The Trap (Distractor Analysis):

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• Why not Option A?
  While AWS::Lambda::Function is a valid CloudFormation resource, it misses the point of leveraging AWS SAM’s simplified syntax and model. SAM provides higher-level abstractions that automate a lot of boilerplate related to permissions, event sources, and packaging.

• Why not Option B?
  The Mappings section is intended for key-value maps used for parameterization—it does not define resources. Defining resources like AWS::Serverless::Function belongs in the Resources section and requires the Transform declaration.

• Why not Option D?
  The Parameters section allows passing input values at deployment time, but the AWS SAM Globals section is a separate top-level section used to reduce repetition for resource properties. Defining Globals in Parameters is invalid and does not cause CloudFormation to interpret the template as SAM.

The Technical Blueprint

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# Example snippet showing the essential Transform declaration at template top:
Transform: AWS::Serverless-2016-10-31

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs18.x
      Events:
        ApiEvent:
          Type: Api
          Properties:
            Path: /hello
            Method: get

The Comparative Analysis

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Real-World Application (Practitioner Insight)

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Exam Rule

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For the exam, always pick Option C when you see any mention of AWS SAM resources (AWS::Serverless::*). Recognize the critical role of the Transform declaration.

Real World

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In practice, teams frequently start with native Lambda and API Gateway resources (Option A) but switch to SAM for faster iteration and less boilerplate. Knowing when and how to leverage the Transform directive accelerates developer productivity.

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Disclaimer

This is a study note based on simulated scenarios for the AWS DVA-C02 exam.