Amazon Web Services DVA-C02 - AWS Certified Developer - Associate

AWS CloudFormation is a service that enables developers to model and provision AWS resources using templates. The developer can use the following steps to avoid accidental database deletion in the future:

Set up AWS CodeDeploy to deploy the most recent version of the application at runtime. This will ensure that the application code is always up to date and does not depend on the AMI.

Remove any commands that perform operating system patching from the UserData script. This will reduce the time that the UserData script takes to run and speed up the instance launch process.

Requirement Summary:

DynamoDB table Orders

Partition key: OrderID

No sort key

100,000+ records

Need to efficiently retrieve all records where:

OrderSource = "MobileApp"

Must optimize for user experience (i.e., performance)

Evaluate Options:

Option A: Scan with FilterExpression

Inefficient for large tables

A Scan reads every item in the table and then applies a filter condition.

This is slow, expensive, and not scalable as the dataset grows.

Option B: Create a Local Secondary Index (LSI) with OrderSource

Invalid: LSIs require the same partition key (OrderID) as the base table.

Since OrderSource is not part of the primary key, and we want to query based on it, LSI won’t help.

Option C: Create a GSI with OrderSource as the sort key

Misuse of sort key: Querying by sort key alone is not allowed in DynamoDB.

You must specify a partition key in a Query.

This design is not valid for the use case.

Option D: Create a GSI with OrderSource as the partition key

BEST CHOICE: With a GSI on OrderSource, you can query efficiently for all items where OrderSource = "MobileApp".

DynamoDB GSIs allow an alternative access pattern for queries not supported by the base table schema.

GSI Design: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GSI.html

Querying a GSI: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html

Scan vs Query: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/bp-query-scan.html

In CodePipeline, the service designed to run builds, execute unit/integration tests, and produce build artifacts (including test reports) is AWS CodeBuild. CodeBuild runs commands specified in a buildspec.yml file and supports reporting outputs such as test results (for example, JUnit XML), code coverage, and other build metadata.

Option A is correct because the developer can configure the CodeBuild project to run the test suite during the build phase and configure the buildspec to publish test report files. This integrates naturally into CodePipeline as a build stage, and the reports are generated consistently on each pipeline execution.

Option B is incorrect: CodeDeploy is for deploying applications (in-place/blue-green) and lifecycle hooks, not for standard build/test report generation.

Option C increases operational overhead by managing an EC2 build server, which is unnecessary when CodeBuild provides managed build environments.

Option D is unrelated: CodeArtifact is a package repository, not a test reporting solution.

Therefore, use CodeBuild and configure test reports via the buildspec.

Pseudo Parameters: CloudFormation provides pseudo parameters that reference runtime context, including the current AWS Region.

Operational Efficiency: The AWS::Region pseudo parameter offers the most direct and self-contained way to obtain the Region dynamically within the template.

The solution that will solve this problem is to create and inspect the Lambda dead-letter queue. Troubleshoot the failed functions. Reprocess the events. This way, the developer can identify and fix any issues that caused the Lambda function to fail when invoked asynchronously by API Gateway. The developer can also reprocess any orders that were not processed due to failures. The other options either do not address the root cause of the problem, or do not help recover from failures.

Why Option B is Correct:A customer-managed AWS Key Management Service (KMS) key allows for encryption at rest and provides the ability to rotate the key on demand. This ensures compliance with security requirements for key management and database encryption.

RDS integrates natively with AWS KMS, allowing the use of a customer-managed key for encrypting data at rest.

Key rotation can be managed directly in AWS KMS without needing custom solutions.

Why Other Options are Incorrect:

Option A: AWS KMS managed encryption keys (AWS-owned keys) do not support key rotation on demand.

Option C & D: Storing keys in AWS Secrets Manager with custom rotation is not a recommended approach for database encryption. AWS KMS is designed specifically for secure key management and encryption.

AWS Documentation References:

Encrypting Amazon RDS Resources

AWS Key Management Service (KMS)

Requirement Summary:

Store customer orders in DynamoDB

Must encrypt data at rest

Company wants to use a key it generates (i.e., customer managed key)

Evaluate Options:

A. Set encryption to None, manually encrypt/decrypt in code

Overhead and error-prone

Also non-compliant with AWS encryption best practices

B. Use customer managed KMS key

Exactly meets the requirement: customer generates and controls the key

During table creation, you can specify a KMS CMK ARN

C. Default encryption + kms:Encrypt in SDK

Misunderstanding: DynamoDB handles encryption automatically

You don’t need to call kms:Encrypt manually in SDK

D. Use AWS managed key

Does not meet the requirement of using custom company-generated key

DynamoDB encryption: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/EncryptionAtRest.html

KMS customer managed keys: https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#customer-cmk