Question 1

An application running on an Amazon Linux EC2 instance needs to manage the AWS infrastructure. How can the EC2 instance be configured to make AWS API calls securely?

Accepted Answer

Using an IAM role for the EC2 instance allows it to securely make AWS API calls without needing to manage access keys directly. The role provides temporary credentials that are automatically rotated.

Question 2

A company recently migrated its web, application and NoSQL database tiers to AWS. The company is using Auto Scaling to scale the web and application tiers. More than 95 percent of the Amazon DynamoDB requests are repeated read-requests. How can the DynamoDB NoSQL tier be scaled up to cache these repeated requests?

Accepted Answer

Amazon DynamoDB Accelerator (DAX) is a caching service specifically designed to improve the performance of DynamoDB by caching repeated read requests, reducing the response time for such queries.

Question 3

A company is developing a new online game that will run on top of Amazon ECS. Four distinct Amazon ECS services will be part of the architecture, each requiring specific permissions to various AWS services. The company wants to optimize the use of the underlying Amazon EC2 instances by bin packing the containers based on memory reservation. Which configuration would allow the Development team to meet these requirements MOST securely?

Accepted Answer

The answer of A company is developing a new online...

Question 4

An application needs to use the IP address of the client in its processing. The application has been moved into AWS and has been placed behind an Application Load Balancer (ALB). However, all the client IP addresses now appear to be the same. The application must maintain the ability to scale horizontally. Based on this scenario, what is the MOST cost-effective solution to this problem?

Accepted Answer

The X-Forwarded-For header is a standard way to retrieve the original client IP address when using a load balancer like ALB. This solution is cost-effective as it only requires a code change to read the header, without needing to replace the ALB or change the architecture.

Question 5

A Developer is creating a mobile application with a limited budget. The solution requires a scalable service that will enable customers to sign up and authenticate into the mobile application while using the organization's current SAML 2.0 identity provider. Which AWS service should be used to meet these requirements?

Accepted Answer

Amazon Cognito is designed to handle user sign-up, sign-in, and access control, and it supports integration with SAML 2.0 identity providers, making it suitable for the developer's needs.

Question 6

A company is using AWS CodePipeline to deliver one of its applications. The delivery pipeline is triggered by changes to the master branch of an AWS CodeCommit repository and uses AWS CodeBuild to implement the test and build stages of the process and AWS CodeDeploy to deploy the application. The pipeline has been operating successfully for several months and there have been no modifications. Following a recent change to the application's source code, AWS CodeDeploy has not deployed the updates application as expected. What are the possible causes? (Choose two.)

Accepted Answer

The answer of A company is using AWS CodePipeline to...

Question 7

An application displays a status dashboard. The status is updated by 1 KB messages from an SQS queue. Although the status changes infrequently, the Developer must minimize the time between the message arrival in the queue and the dashboard update. What technique provides the shortest delay in updating the dashboard?

Accepted Answer

Long polling reduces the number of empty responses by allowing the poll to wait until a message is available, thus minimizing the delay between message arrival and processing.

Question 8

An application is running on an EC2 instance. The Developer wants to store an application metric in Amazon CloudWatch. What is the best practice for implementing this requirement?

Accepted Answer

CloudWatch PutMetricData API call is the best practice for implementing this requirement because it is a direct and efficient way to send custom metrics to CloudWatch.

Question 9

A company is building an application to track athlete performance using an Amazon DynamoDB table. Each item in the table is identified by a partition key (user_id) and a sort key (sport_name). The table design is shown below:  (Note: Not all table attributes are shown) A Developer is asked to write a leaderboard application to display the top performers (user_id) based on the score for each sport_name. What process will allow the Developer to extract results MOST efficiently from the DynamoDB table?

Accepted Answer

The answer of A company is building an application to...

Question 10

An organization is using Amazon CloudFront to ensure that its users experience low-latency access to its web application. The organization has identified a need to encrypt all traffic between users and CloudFront, and all traffic between CloudFront and the web application. How can these requirements be met? (Choose two.)

Accepted Answer

The answer of An organization is using Amazon CloudFront to...

Question 11

A Developer uses AWS CodeDeploy to automate application deployment that connects to an external MySQL database. The Developer wants to securely access the encrypted secrets, such as API keys and database passwords. Which of the following solutions would involve the LEAST administrative effort?

Accepted Answer

The answer of A Developer uses AWS CodeDeploy to automate...

Question 12

A social media company is using Amazon Cognito in order to synchronize profiles across different mobile devices, to enable end users to have a seamless experience. Which of the following configurations can be used to silently notify users whenever an update is available on all other devices?

Accepted Answer

The answer of A social media company is using Amazon...

Question 13

A Developer will be using the AWS CLI on a local development server to manage AWS services. What can be done to ensure that the CLI uses the Developer's IAM permissions when making commands?

Accepted Answer

The aws configure CLI command allows the user to specify the IAM access key ID and secret access key, which will be used for all subsequent CLI commands until the configuration is changed.

Question 14

An application is using Amazon DynamoDB as its data store, and should be able to read 100 items per second as strongly consistent reads. Each item is 5 KB in size. To what value should the table's provisioned read throughput be set?

Accepted Answer

Each strongly consistent read of an item up to 4 KB requires 1 read capacity unit. Since each item is 5 KB, it requires 2 read capacity units per read. Therefore, for 100 items per second, 200 read capacity units are needed.

Question 15

According to best practice, how should access keys be managed in AWS? (Choose two.)

Accepted Answer

Access keys for the root user should be deleted to enhance security, as the root account has full access to all resources. Using IAM roles is preferred over access keys because roles provide temporary security credentials and reduce the risk of long-term exposure.

Question 16

A Developer is using AWS CLI, but when running list commands on a large number of resources, it is timing out. What can be done to avoid this time-out?

Accepted Answer

Using pagination allows the AWS CLI to handle large sets of data by retrieving them in smaller, more manageable chunks, thus preventing time-outs.

Question 17

An on-premises application makes repeated calls to store files to Amazon S3. As usage of the application has increased, "LimitExceeded" errors are being logged. What should be changed to fix this error?

Accepted Answer

Implementing exponential backoffs helps manage API request limits by gradually increasing the wait time between retries, reducing the likelihood of hitting the limit again.

Question 18

An application uses Lambda functions to extract metadata from files uploaded to an S3 bucket; the metadata is stored in Amazon DynamoDB. The application starts behaving unexpectedly, and the Developer wants to examine the logs of the Lambda function code for errors. Based on this system configuration, where would the Developer find the logs?

Accepted Answer

Lambda function logs are automatically sent to Amazon CloudWatch Logs, where developers can view and analyze them.

Question 19

An on-premises legacy application is caching data files locally and writing shared images to local disks. What is necessary to allow for horizontal scaling when migrating the application to AWS?

Accepted Answer

To enable horizontal scaling, the application should use Amazon S3 for both caching data and storing shared images, as S3 provides scalable storage that can be accessed by multiple instances.

Question 20

An application runs on multiple EC2 instances behind an ELB. Where is the session data best written so that it can be served reliably across multiple requests?

Accepted Answer

Amazon ElastiCache is a managed in-memory data store that can be used to store session data, allowing it to be accessed quickly and reliably across multiple EC2 instances.

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