AWS Certified Developer - Associate (DVA-C02) - Exam 1

You are building a web application that uses API Gateway to expose a Lambda function to process requests from clients over the internet. While testing, the API Gateway frequently times out; however, when calling the Lambda function directly, it completes successfully every time.

Which of the following API Gateway metrics in Amazon CloudWatch should you check in order to troubleshoot the issue?

(Choose 2)

• Latency

• IntegrationLatency

• CacheMissCount

• Count

You are developing a web application that has been deployed using Lambda. Today, you updated the code and uploaded the new version of your code to the Lambda console. Your test team has begun their testing, and has reported that the application seems to still be using the original code. What could be the reason for this?

• Your application is referencing the function using $LATEST.

• Your application is referencing the function using an alias that points to a previous version of the code.

• Your application is referencing the function using an unqualified ARN.

• After deploying the function, there is usually a delay in which the new function is initialized. During this time, the application is directed to the previous version of the function.

What does the following snippet from an IAM policy do?

• Allows full access to the bucket named mycustomerdata, including the objects it contains.

• Denies the ability to delete any objects with log in the name from the mycustomerdata bucket, while allowing all other S3 actions.

• Allows the ability to delete any objects with log in the name from the mycustomerdata bucket.

• Denies the ability to read objects contained in the bucket named mycustomerdata.

• Allows only read access for all objects contained in the bucket named mycustomerdata.

You have a simple, stateless Python application that processes the contents of an S3 bucket once an hour and takes about six minutes to complete once started. Which AWS service should you run this application on in order to provide the most reliable and cost-effective solution?

• Make the application a Lambda function, and create a scheduled event trigger set to one hour.

• Create a CloudFront endpoint, and point it to an S3 bucket. Run the application from that bucket.

• Create an Auto Scaling group for an EC2 instance. Run the application on that instance with crontab set to 1 hour.

• Create an ECS cluster and run the application as a service on that cluster.

You are deploying a new version of your application using a CodeDeploy in-place upgrade. At the end of the deployment, you test the application and discover that something has gone wrong. You need to roll back your changes as quickly as possible. What do you do?

• Use the CodeDeploy roll back feature to seamlessly roll back to the previous version.

• Use CodeDeploy to redeploy the previous version of the application.

• Point all incoming requests to your development environment while you fix the problem with the failed deployment.

• Configure your load balancer to send all incoming requests to the original instances running the old version of the application.

You've created an online forum where your users can post questions and comments. The thread table has many users, and each user has many posts, each marked by a timestamp. Which primary key configuration would be best suited to see all posts by a particular user in chronological order?

• A composite key with UserID as the sort key and timestamp as the hash key.

• A composite key with UserID as the sort key and timestamp as the partition key.

• A composite key with UserID as the partition key and timestamp as the sort key.

• A composite key with UserID as the range key and timestamp as the sort key.

You are designing an application that consumes a large amount of unstructured streaming data. The data needs to be processed and then stored persistently so that a team of analysts can generate reports by running SQL queries on the data. How would you design this application?

• Use Kinesis Firehose to capture the streaming data, use Lambda to process the data, and store the processed data in DynamoDB.

• Use Kinesis Firehose to capture the streaming data, use Lambda to process the data, and store the processed data in S3. Use Athena to run the SQL queries.

• Use EventBridge to capture the streaming data, use Lambda to process the data, and store the processed data in DynamoDB.

• Use Kinesis Firehose to capture the streaming data, use EventBridge to process the data, and store the processed data in S3. Use Athena to run the SQL queries.

You are designing a serverless online banking application that uses a Lambda function to process a credit check for new customers. The Lambda function makes an API call to an external third-party credit checking agency that performs the credit check and returns a response.

During performance testing, you discover that under peak load conditions, the third-party credit check API sometimes times out or returns an error, causing your function to fail. The support team has requested to receive notifications if the credit check API error rate exceeds 10% of the total number of transactions in any given hour. Which solution will meet these requirements?

• Publish custom metrics to CloudWatch that record the failures of the credit check API calls. Configure a CloudWatch alarm to notify an SNS topic when the error rate exceeds the specified rate.

• Publish the failed credit check API calls to an SQS queue for further processing. Configure a CloudWatch alarm to send a message to the SQS queue when error rate exceeds the specified rate.

• Publish the Lambda errors to CloudWatch Logs. Configure a Lambda function to query the CloudWatch Logs and notify an SNS topic when the error rate exceeds the specified rate.

• Publish the results of the credit check to a DynamoDB table. Configure a Lambda function to query the table for failed invocations and notify an SNS topic when the error rate exceeds the specified rate.

Your application needs to store RDS database credentials that need rotating automatically, as well as license keys. Which of the following services can you use to achieve this?

(Choose2)

• Use Parameter Store to store the database credentials.

• Use IAM to store the database credentials.

• Use Systems Manager Parameter Store to store the license keys.

• Use S3 to store the license keys.

• Use Secrets Manager to store the database credentials.

Which HTTP response code indicates that an API call was successful?

• 200

• 500

• 400

• 300