DVA-C02 Free Practice Test

A developer has observed an increase in bugs in the AWS Lambda functions that a development team has deployed in its Node is application. To minimize these bugs, the developer wants to impendent automated testing of Lambda functions in an environment that Closely simulates the Lambda environment.
The developer needs to give other developers the ability to run the tests locally. The developer also needs to integrate the tests into the team's continuous integration and continuous delivery (Ct/CO) pipeline before the AWS Cloud Development Kit (AWS COK) deployment.
Which solution will meet these requirements?

1. A. Create sample events based on the Lambda documentatio
2. B. Create automated test scripts that use the cdk local invoke command to invoke the Lambda function
3. C. Check the response Document the test scripts for the other developers on the team Update the CI/CD pipeline to run the test scripts.
4. D. Install a unit testing framework that reproduces the Lambda execution environmen
5. E. Create sample events based on the Lambda Documentation Invoke the handler function by using a unit testing framewor
6. F. Check the response Document how to run the unit testingframework for the other developers on the tea
7. G. Update the OCD pipeline to run the unit testing framework.
8. H. Install the AWS Serverless Application Model (AWS SAW) CLI tool Use the Sam local generate-event command to generate sample events for me automated test
9. I. Create automated test scripts that use the Sam local invoke command to invoke the Lambda function
10. J. Check the response Document the test scripts tor the other developers on the team Update the CI/CD pipeline to run the test scripts.
11. K. Create sample events based on the Lambda documentatio
12. L. Create a Docker container from the Node is base image to invoke the Lambda function
13. M. Check the response Document how to run the Docker container for the more developers on the team update the CI/CD pipeline to run the Docker container.

Correct Answer: C
This solution will meet the requirements by using AWS SAM CLI tool, which is a command line tool that lets developers locally build, test, debug, and deploy serverless applications defined by AWS SAM templates. The developer can use sam local generate- event command to generate sample events for different event sources such as API Gateway or S3. The developer can create automated test scripts that use sam local invoke command to invoke Lambda functions locally in an environment that closely simulates Lambda environment. The developer can check the response from Lambda functions and document how to run the test scripts for other developers on the team. The developer can also update CI/CD pipeline to run these test scripts before deploying with AWS CDK. Option A is not optimal because it will use cdk local invoke command, which does not exist in AWS CDK CLI tool. Option B is not optimal because it will use a unit testing framework that reproduces Lambda execution environment, which may not be accurate or consistent with Lambda environment. Option D is not optimal because it will create a Docker container from Node.js base image to invoke Lambda functions, which may introduce additional overhead and complexity for creating and running Docker containers.
References: [AWS Serverless Application Model (AWS SAM)], [AWS Cloud Development Kit (AWS CDK)]

A company runs an application on AWS The application stores data in an Amazon DynamoDB table Some queries are taking a long time to run These slow queries involve an attribute that is not the table's partition key or sort key
The amount of data that the application stores in the DynamoDB table is expected to increase significantly. A developer must increase the performance of the queries.
Which solution will meet these requirements'?

1. A. Increase the page size for each request by setting the Limit parameter to be higher than the default value Configure the application to retry any request that exceeds the provisioned throughput.
2. B. Create a global secondary index (GSI). Set query attribute to be the partition key of the index
3. C. Perform a parallel scan operation by issuing individual scan requests in the parameters specify the segment for the scan requests and the total number of segments for the parallel scan.
4. D. Turn on read capacity auto scaling for the DynamoDB tabl
5. E. Increase the maximum read capacity units (RCUs).

Correct Answer: B
Creating a global secondary index (GSI) is the best solution to improve the performance of the queries that involve an attribute that is not the table’s partition key or sort key. A GSI allows you to define an alternate key for your table and query the data using that key. This way, you can avoid scanning the entire table and reduce the latency and cost of your queries. You should also follow the best practices for designing and using GSIs in DynamoDB12. References
✑ Working with Global Secondary Indexes - Amazon DynamoDB
✑ DynamoDB Performance & Latency - Everything You Need To Know

A company hosts a client-side web application for one of its subsidiaries on Amazon S3. The web application can be accessed through Amazon CloudFront from https://www.example.com. After a successful rollout, the company wants to host three more client-side web applications for its remaining subsidiaries on three separate S3 buckets.
To achieve this goal, a developer moves all the common JavaScript files and web fonts to a central S3 bucket that serves the web applications. However, during testing, the developer notices that the browser blocks the JavaScript files and web fonts.
What should the developer do to prevent the browser from blocking the JavaScript files and web fonts?

1. A. Create four access points that allow access to the central S3 bucke
2. B. Assign an access point to each web application bucket.
3. C. Create a bucket policy that allows access to the central S3 bucke
4. D. Attach the bucket policy to the central S3 bucket.
5. E. Create a cross-origin resource sharing (CORS) configuration that allows access to the central S3 bucke
6. F. Add the CORS configuration to the central S3 bucket.
7. G. Create a Content-MD5 header that provides a message integrity check for the central S3 bucke
8. H. Insert the Content-MD5 header for each web application request.

Correct Answer: C
This is a frequent trouble. Web applications cannot access the resources in other domains by default, except some exceptions. You must configure CORS on the resources to be accessed. https://docs.aws.amazon.com/AmazonS3/latest/userguide/cors.html

A developer is writing a serverless application that requires an AWS Lambda function to be invoked every 10 minutes.
What is an automated and serverless way to invoke the function?

1. A. Deploy an Amazon EC2 instance based on Linux, and edit its /etc/confab file by adding a command to periodically invoke the lambda function
2. B. Configure an environment variable named PERIOD for the Lambda functio
3. C. Set the value to 600.
4. D. Create an Amazon EventBridge rule that runs on a regular schedule to invoke the Lambda function.
5. E. Create an Amazon Simple Notification Service (Amazon SNS) topic that has a subscription to the Lambda function with a 600-second timer.

Correct Answer: C
The solution that will meet the requirements is to create an Amazon EventBridge rule that runs on a regular schedule to invoke the Lambda function. This way, the developer can use an automated and serverless way to invoke the function every 10 minutes. The developer can also use a cron expression or a rate expression to specify the schedule for the rule. The other options either involve using an Amazon EC2 instance, which is not serverless, or using environment variables or query parameters, which do not trigger the function.
Reference: Schedule AWS Lambda functions using EventBridge

An Amazon Simple Queue Service (Amazon SQS) queue serves as an event source for an AWS Lambda function In the SQS queue, each item corresponds to a video file that the Lambda function must convert to a smaller resolution The Lambda function is timing out on longer video files, but the Lambda function's timeout is already configured to its maximum value
What should a developer do to avoid the timeouts without additional code changes'?

1. A. Increase the memory configuration of the Lambda function
2. B. Increase the visibility timeout on the SQS queue
3. C. Increase the instance size of the host that runs the Lambda function.
4. D. Use multi-threading for the conversion.

Correct Answer: A
Increasing the memory configuration of the Lambda function will also increase the CPU and network throughput available to the function. This can improve theperformance of the video conversion process and reduce the execution time of the function. This solution does not require any code changes or additional resources. It is also recommended to follow the best practices for preventing Lambda function
timeouts1. References
✑ Troubleshoot Lambda function invocation timeout errors | AWS re:Post