Free Practice Questions for Amazon Web Services DVA-C02 Exam

Requirement Summary:

Users experiencebuffering/delaywhen starting video stream

Architecture:

CloudFront → API Gateway → Lambda → DynamoDB

Need toidentify root causeof performance issues

Evaluate Options:

✅A: Enable AWS X-Ray tracing

✅Ideal forend-to-end tracing

Visualizeslatency across services (API Gateway, Lambda, DynamoDB)

Creates aservice mapfor easy identification of bottlenecks or errors

Designed specifically fordistributed tracingand performance monitoring

B: CloudWatch Logs Insights

⚠️Helpful for querying logs

But lacks thevisual trace linkageacross services like X-Ray

Does not identifywhere latency accumulates

C: AWS Config

❌Tracks configuration changes,not runtime performance

D: CloudTrail + CloudWatch Logs

❌More useful foraudit/logging, not tracing performance or latency issues

X-Ray overview:https://docs.aws.amazon.com/xray/latest/devguide/aws-xray.html

Service map:https://docs.aws.amazon.com/xray/latest/devguide/xray-console-service-map.html

Tracing API Gateway:https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-xray.html

Lambda Layers: These are designed to package dependencies that you can share across functions.

How to Use:

Create a layer, upload your 100MB library as a zip.

Attach the layer to your function.

In your function code, import the library from the standard layer path.

This solution will meet the requirements by ensuring that all traffic between users and CloudFront, and all traffic between CloudFront and the web application, are encrypted using HTTPS protocol. The Origin Protocol Policy determines how CloudFront communicates with the origin server (the web application), and setting it to “HTTPS Only” will force CloudFront to use HTTPS for every request to the origin server. The Viewer Protocol Policy determines how CloudFront responds to HTTP or HTTPS requests from users, and setting it to “HTTPS Only” or “Redirect HTTP to HTTPS” will force CloudFront to use HTTPS for every response to users. Option A is not optimal because it will use AWS KMS to encrypt traffic between CloudFront and the web application, which is not necessary or supported by CloudFront. Option C is not optimal because it will set the origin’s HTTP port to 443, which is incorrect as port 443 is used for HTTPS protocol, not HTTP protocol. Option E is not optimal because it will enable the CloudFront option Restrict Viewer Access, which is used for controlling access to private content using signed URLs or signed cookies, not for encrypting traffic.

Comprehensive and Detailed Step-by-Step Explanation:

Option D: Use Lambda with Container Images

AWS Lambda supports container images up to 10 GB in size, making it suitable for applications with large dependencies, such as a video codec library larger than 250 MB.

By creating separate container images for video compression and decompression, the application can efficiently isolate functionality while ensuring that each function includes the required dependencies.

The container images are stored in Amazon ECR and used to create the Lambda functions.

Why Other Options Are Incorrect:

Option A:A single Lambda function with all functionalities and dependencies in one zip file is not feasible due to the 250 MB deployment package size limit for zip files.

Option B:Including the library in two separate zip files still exceeds the size limit for Lambda zip deployment packages.

Option C:While using a Lambda layer can reduce redundancy, the combined size of the layer and the zip files would exceed the limit of 250 MB.

This solution allows the environment variables to be passed to the container when it is launched by AWS Fargate using Amazon ECS. The task definition is a text file that describes one or more containers that form an application. It contains various parameters for configuring the containers, such as CPU and memory requirements, network mode, and environment variables. The environment parameter is an array of key-value pairs that specify environment variables to pass to a container. Defining an array that includes the environment variables under the entryPoint parameter within the task definition will not pass them to the container, but use them as command-line arguments for overriding the default entry point of a container. Defining an array that includes the environment variables under the environment or entryPoint parameter within the service definition will not pass them to the container, but cause an error because these parameters are not valid for a service definition.

Amazon RDS for MySQL supports read replicas, which are copies of the primary database instance that can handle read-only queries. Read replicas can improve the read performance ofthe database by offloading the read workload from the primary instance and distributing it across multiple replicas. To use read replicas, the application code needs to be modified to direct read queries to the URL of the read replicas, while write queries still go to the URL of the primary instance. This solution requires less current and future effort than using a multi-AZ deployment, which does not provide read scaling benefits, or using open source replication software, which requires additional configuration and maintenance. Reference: Working with read replicas

S3Bucket and S3Key: These properties in a CloudFormation AWS::Lambda::Function resource specify the location of the function's code in S3.

Least Development Effort: This solution minimizes code changes, relying on CloudFormation to reference the existing S3 deployment package.

Amazon Machine Images (AMIs) are encrypted snapshots of EC2 instances that can be used to launch new instances. The developer can create new AMIs from the existing instances and specify encryption parameters. The developer can copy the encrypted AMIs to the destination Region and use them to create a new application stack. The developer can delete the unencrypted AMIs after the encryption process is complete. This solution will meet the encryption requirement and allow the developer to expand the application to run in the destination Region.