Amazon DVA-C02 Practice Test - Questions Answers, Page 16

Scenario:Application needs to fetch songs and artists efficiently in a single operation.

BatchGetItem:This DynamoDB operation retrieves multiple items across different tables based on their primary keys in a single request.

Optimized for Request Batching:This approach reduces network traffic compared to performing multiple queries individually.

Data Modeling:Thesongstable is designed appropriately for this access pattern usingartistNameas the sort key.

Amazon DynamoDB BatchGetItem:https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_BatchGetItem.ht

Secrets Management:AWS Secrets Manager is designed specifically for storing and managing sensitive credentials.

Environment Isolation:Creating separate secrets for each environment (development, staging, etc.) ensures clear separation and prevents accidental leaks.

Automatic Rotation:Secrets Manager provides built-in rotation capabilities, enhancing security posture.

AWS Secrets Manager:https://aws.amazon.com/secrets-manager/

Secrets Manager Rotation:https://docs.aws.amazon.com/secretsmanager/latest/userguide/rotating-secrets.html

Problem: CloudFormation updates reset Parameter Store parameters, disrupting application behavior.

Deletion Policy: CloudFormation has a deletion policy that controls resource behavior when a stack is deleted or updated. The 'Retain' policy instructs CloudFormation to preserve a resource's current state.

Least Development Effort: This solution involves a simple CloudFormation template modification, requiring minimal code changes.

CloudFormation Deletion Policies:https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-deletionpolicy.html

Problem: Large bundle size increases Lambda deployment time.

Lambda Layers: Layers let you package dependencies separately from your function code. This optimizes the deployment package, making updates faster.

Modularization: Breaking down dependencies into layers improves code organization and reusability.

AWS Lambda Layers:https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html

API Gateway Stage Variables: These are designed for configuring dynamic values for your APIs in different deployment stages (dev, test, prod). Here's how to use them for third-party endpoints:

In the API Gateway console,access the 'Stages' section of your API.

For each stage,create a stage variable named something likethirdPartyEndpoint.

Set the value of this variable to the actual endpoint URL for that specific environment.

When configuring API requests within your API Gateway method,reference this endpoint using${stageVariables.thirdPartyEndpoint}.

Why Stage Variables Excel Here:

Environment Isolation:This approach keeps the endpoint configuration specific to each deployment stage,ensuring the right endpoints are used during development,testing,and production cycles.

Ease of Management:You manage the endpoints directly through the API Gateway console without additional infrastructure.

Amazon API Gateway Stage Variables:https://docs.aws.amazon.com/apigateway/latest/developerguide/stage-variables.html

SQS Delivery Behavior:Standard SQS queues guarantee at-least-once delivery, meaning messages may be processed more than once. This can lead to duplicate emails in this scenario.

Visibility Timeout:If the visibility timeout on the SQS queue is too short, a message might become visible for another consumer before the first Lambda function finishes processing it. This can also lead to duplicates.

Amazon SQS Delivery Semantics:[invalid URL removed]

Amazon SQS Visibility Timeout:https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-visibility-timeout.html

API Gateway Mocking:This feature is built for decoupling development dependencies. Here's the process:

Create resources and methods in your API Gateway.

Set the integration type to 'MOCK'.

Define Integration Responses, mapping HTTP status codes to desired mocked responses (JSON, etc.).

Deployment and Use:

Create a deployment stage for the API.

Frontend teams can call this API and get the mocked responses without a real backend.

Mocking API Gateway APIs:https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-mock-integration.html

IAM Roles for EC2 (A):The most secure way to provide AWS permissions from EC2.

Create a role with a policy allowings3:GetObjecton the specific bucket.

Attach the role to an instance profile and associate that profile with your instances.

Pre-signed URLs (C):Temporary, authenticated URLs for specific S3 actions.

Modify the app to use the AWS SDK to callGeneratePresignedUrl.

Embed these URLs when a user is properly logged in, allowing download access.

IAM Roles for EC2:https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_use_switch-role-ec2.html

Generating Presigned URLs:https://docs.aws.amazon.com/AmazonS3/latest/userguide/ShareObjectPreSignedURL.htm

Principle of Least Privilege:Granting specific permissions through an IAM role is more secure than directly attaching policies to a function or using root user credentials.

IAM Roles for Lambda:Designed to provide temporary credentials to Lambda functions, enhancing security.

Reusability:The existing IAM policy ensures the correct S3 and DynamoDB access is granted.

IAM Roles for Lambda Documentation:https://docs.aws.amazon.com/lambda/latest/dg/lambda-intro-execution-role.html

IAM Best Practices:https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html