Question 1

A developer needs to manage AWS infrastructure as code and must be able to deploy multiple identical copies of the infrastructure, stage changes, and revert to previous versions. Which approach addresses these requirements?

Accepted Answer

AWS CloudFormation allows managing infrastructure as code, enabling the deployment of multiple identical copies, staging changes, and reverting to previous versions. AWS CodeCommit can be used for version control of the infrastructure code.

Question 2

A Developer is migrating existing applications to AWS. These applications use MongoDB as their primary data store, and they will be deployed to Amazon EC2 instances. Management requires that the Developer minimize changes to applications while using AWS services. Which solution should the Developer use to host MongoDB in AWS?

Accepted Answer

The answer of A Developer is migrating existing applications to...

Question 3

A company wants to containerize an existing three-tier web application and deploy it to Amazon ECS Fargate. The application is using session data to keep track of user activities. Which approach would provide the BEST user experience?

Accepted Answer

The answer of A company wants to containerize an existing...

Question 4

A Developer has an application that must accept a large amount of incoming data streams and process the data before sending it to many downstream users. Which serverless solution should the Developer use to meet these requirements?

Accepted Answer

Amazon Kinesis Data Streams is designed to handle large amounts of incoming data streams and can be integrated with AWS Lambda to process the data in real-time before sending it to downstream users.

Question 5

A developer is writing an AWS Lambda function. The developer wants to log key events that occur during the Lambda function and include a unique identifier to associate the events with a specific function invocation. Which of the following will help the developer accomplish this objective?

Accepted Answer

The Lambda context object provides a unique request identifier for each invocation, which can be used to associate logs with a specific function invocation. Writing logs to the console is the standard practice in AWS Lambda, as these logs are automatically captured by AWS CloudWatch Logs.

Question 6

An application is experiencing performance issues based on increased demand. This increased demand is on read-only historical records pulled from an Amazon RDS-hosted database with custom views and queries. A Developer must improve performance without changing the database structure. Which approach will improve performance and MINIMIZE management overhead?

Accepted Answer

Using Amazon ElastiCache for Redis allows caching of frequently accessed data, improving read performance without altering the database structure, and it minimizes management overhead compared to managing a custom caching solution on EC2.

Question 7

A developer is building an application using an Amazon API Gateway REST API backend by an AWS Lambda function that interacts with an Amazon DynamoDB table. During testing, the developer observes high latency when making requests to the API. How can the developer evaluate the end-to-end latency and identify performance bottlenecks?

Accepted Answer

AWS X-Ray provides end-to-end tracing capabilities, allowing the developer to trace and analyze user requests as they travel through the API Gateway, Lambda function, and DynamoDB, helping to identify latency and performance bottlenecks.

Question 8

A developer has built a market application that stores pricing data in Amazon DynamoDB with Amazon ElastiCache in front. The prices of items in the market change frequently. Sellers have begun complaining that, after they update the price of an item, the price does not actually change in the product listing. What could be causing this issue?

Accepted Answer

The cache is not being invalidated when the price of the item is changed, leading to stale data being served from the cache instead of the updated data from DynamoDB.

Question 9

A Developer has an Amazon DynamoDB table that must be in provisioned mode to comply with user requirements. The application needs to support the following: Average item size: 10 KB Item reads each second: 10 strongly consistent Item writes each second: 2 transactional Which read and write capacity cost-effectively meets these requirements?

Accepted Answer

For strongly consistent reads, each read capacity unit supports up to 4 KB per second. Since the average item size is 10 KB, each read will require 3 read capacity units (10 KB / 4 KB = 2.5, rounded up to 3). For 10 reads per second, 30 read capacity units are needed (10 reads * 3 units). Each write capacity unit supports 1 KB per second, so for 10 KB items, each write requires 10 write capacity units. For 2 transactional writes per second, 20 write capacity units are needed (2 writes * 10 units). However, option A is the closest cost-effective choice that meets the requirement with minimal over-provisioning.

Question 10

A developer is using Amazon DynamoDB to store application data. The developer wants to further improve application performance by reducing response times for read and write operations. Which DynamoDB feature should be used to meet these requirements?

Accepted Answer

The answer of A developer is using Amazon DynamoDB to...

Question 11

A Developer is designing an AWS Lambda function that create temporary files that are less than 10 MB during execution. The temporary files will be accessed and modified multiple times during execution. The Developer has no need to save or retrieve these files in the future. Where should the temporary file be stored?

Accepted Answer

The /tmp directory is a local storage available to AWS Lambda functions for temporary files, and it is suitable for files that are accessed and modified multiple times during execution. It is ephemeral and does not persist beyond the function execution, which fits the requirement of not needing to save or retrieve the files in the future.

Question 12

A front-end web application is using Amazon Cognito user pools to handle the user authentication flow. A developer is integrating Amazon DynamoDB into the application using the AWS SDK for JavaScript. How would the developer securely call the API without exposing the access or secret keys?

Accepted Answer

The developer should use Amazon Cognito identity pools to exchange the JWT for temporary AWS credentials, which can then be used to securely call the DynamoDB API without exposing access or secret keys.

Question 13

A company is managing a NoSQL database on-premises to host a critical component of an application, which is starting to have scaling issues. The company wants to migrate the application to Amazon DynamoDB with the following considerations: Optimize frequent queries Reduce read latencies Plan for frequent queries on certain key attributes of the table Which solution would help achieve these objectives?

Accepted Answer

Creating global secondary indexes on keys that are frequently queried allows for optimized query performance and reduced read latencies by enabling efficient access patterns for those specific attributes.

Question 14

A developer has written an AWS Lambda function using Java as the runtime environment. The developer wants to isolate a performance bottleneck in the code. Which steps should be taken to reveal the bottleneck?

Accepted Answer

The answer of A developer has written an AWS Lambda...

Question 15

A gaming application stores scores for players in an Amazon DynamoDB table that has four attributes: user_id, user_name, user_score, and user_rank. The users are allowed to update their names only. A user is authenticated by web identity federation. Which set of conditions should be added in the policy attached to the role for the dynamodb: PutItem API call?

Accepted Answer

The answer of A gaming application stores scores for players...

Question 16

A developer is creating a script to automate the deployment process for a serverless application. The developer wants to use an existing AWS Serverless Application Model (AWS SAM) template for the application. What should the developer use for the project? (Choose two.)

Accepted Answer

The answer of A developer is creating a script to...

Question 17

Two containerized microservices are hosted on Amazon EC2 ECS. The first microservice reads an Amazon RDS Aurora database instance, and the second microservice reads an Amazon DynamoDB table. How can each microservice be granted the minimum privileges?

Accepted Answer

By setting ECS_ENABLE_TASK_IAM_ROLE to true, each ECS task can assume its own IAM role, allowing for fine-grained permissions. This enables assigning specific read-only access to the Aurora database for the first microservice and read-only access to DynamoDB for the second microservice, adhering to the principle of least privilege.

Question 18

An application is using a single-node Amazon ElastiCache for Redis instance to improve read performance. Over time, demand for the application has increased exponentially, which has increased the load on the ElastiCache instance. It is critical that this cache layer handles the load and is resilient in case of node failures. What can the Developer do to address the load and resiliency requirements?

Accepted Answer

Adding a read replica instance can help distribute the read load and improve resiliency by providing a failover option in case the primary node fails.

Question 19

A developer is migrating code to an AWS Lambda function that will an Amazon Aurora MySQL database. What is the MOST secure way to authenticate the function to the database?

Accepted Answer

AWS Secrets Manager is the most secure way to manage and rotate database credentials automatically, ensuring that the Lambda function can authenticate securely without hardcoding credentials.

Question 20

A developer is writing an application that will process data delivered into an Amazon S3 bucket. The data is delivered approximately 10 times a day, and the developer expects the data will be processed in less than 1 minute, on average. How can the developer deploy and invoke the application with the lowest cost and lowest latency?

Accepted Answer

Using an S3 event notification to trigger an AWS Lambda function is cost-effective and provides low latency, as it directly invokes the function when a new object is uploaded to the S3 bucket.

Exam 6: AWS Certified Developer Associate (DVA-C01)