Question 1

A Developer is creating a Lambda function that will generate and export a file. The function requires 100 MB of temporary storage for temporary files while executing. These files will not be needed after the function is complete. How can the Developer MOST efficiently handle the temporary files?

Accepted Answer

A)  Store the files in EBS and delete the files at the end of the Lambda function. 
B)  Copy the files to EFS and delete the files at the end of the Lambda function. 
C)  Store the files in the /tmp directory and delete the files at the end of the Lambda function. 
D)  Copy the files to an S3 bucket with a lifecycle policy to delete the files.

Question 2

A company has a web application that uses an Amazon Cognito user pool for authentication. The company wants to create a login page with the company logo. What should a Developer do to meet these requirements?

Accepted Answer

A)  Create a hosted user interface in Amazon Cognito and customize it with the company logo. 
B)  Create a login page with the company logo and upload it to Amazon Cognito. 
C)  Create a login page in Amazon API Gateway with the logo and save the link in Amazon Cognito. 
D)  Upload the logo to the Amazon Cognito app settings and point to the logo on a custom login page.

Question 3

Company A has an S3 bucket containing premier content that they intend to make available to only paid subscribers of their website. The S3 bucket currently has default permissions of all objects being private to prevent inadvertent exposure of the premier content to non-paying website visitors. How can Company A provide only paid subscribers the ability to download a premier content file in the S3 bucket?

Accepted Answer

A)  Apply a bucket policy that grants anonymous users to download the content from the S3 bucket 
B)  Generate a pre-signed object URL for the premier content file when a paid subscriber requests a download 
C)  Add a bucket policy that requires Multi-Factor Authentication for requests to access the S3 bucket objects 
D)  Enable server side encryption on the S3 bucket for data protection against the non-paying website visitors

Question 4

A gaming company is developing a mobile game application for iOS® and Android® platforms. This mobile game securely stores user data locally on the device. The company wants to allow users to use multiple device for the game, which requires user data synchronization across device. Which service should be used to synchronize user data across devices without the need to create a backend application?

Accepted Answer

A)  AWS Lambda 
B)  Amazon S3 
C)  Amazon DynamoDB 
D)  Amazon Cognito

Question 5

Where should the appspec.yml file be placed in order for AWS CodeDeploy to work?

Accepted Answer

A)  In the root of the application source code directory structure 
B)  In the bin folder along with all the complied code 
C)  In an S3 bucket 
D)  In the same folder as the application configuration files

Question 6

A developer is building an application integrating an Amazon API Gateway with an AWS Lambda function. When calling the API, the developer receives the following error: Wed Nov 08 01:13:00 UTC 2017 : Method completed with status: 502 What should the developer do to resolve the error?

Accepted Answer

A)  Change the HTTP endpoint of the API to an HTTPS endpoint 
B)  Change the format of the payload sent to the API Gateway 
C)  Change the format of the Lambda function response to the API call 
D)  Change the authorization header in the API call to access the Lambda function

Question 7

A company's website runs on an Amazon EC2 instance and uses Auto Scaling to scale the environment during peak times. Website users across the world are experiencing high latency due to static content on the EC2 instance, even during non-peak hours. Which combination of steps will resolve the latency issue? (Choose two.)

Accepted Answer

A)  Double the Auto Scaling group's maximum number of servers. 
B)  Host the application code on AWS Lambda. 
C)  Scale vertically by resizing the EC2 instances. 
D)  Create an Amazon CloudFront distribution to cache the static content. 
E)  Store the application's static content in Amazon S3.

Question 8

An application is expected to process many files. Each file takes four minutes to process each AWS Lambda invocation. The Lambda function does not return any important data. What is the fastest way to process all the files?

Accepted Answer

A)  First split the files to make them smaller, then process with synchronous RequestResponse Lambda invocations. First split the files to make them smaller, then process with synchronous RequestResponse Lambda invocations. 
B)  Make synchronous RequestResponse Lambda invocations and process the files one by one. Make synchronous Lambda invocations and process the files one by one. 
C)  Make asynchronous Event Lambda invocations and process the files in parallel. Make asynchronous Event Lambda invocations and process the files in parallel. 
D)  First join all the files, then process it all at once with an asynchronous Event Lambda invocation. First join all the files, then process it all at once with an asynchronous Lambda invocation.

Question 9

A Developer wants to debug an application by searching and filtering log data. The application logs are stored in Amazon CloudWatch Logs. The Developer creates a new metric filter to count exceptions in the application logs. However, no results are returned from the logs. What is the reason that no filtered results are being returned?

Accepted Answer

A)  A setup of the Amazon CloudWatch interface VPC endpoint is required for filtering the CloudWatch Logs in the VPC 
B)  CloudWatch Logs only publishes metric data for events that happen after the filter is created 
C)  The log group for CloudWatch Logs should be first streamed to Amazon Elasticsearch Service before metric filtering returns the results 
D)  Metric data points for logs groups can be filtered only after they are exported to an Amazon S3 bucket

Question 10

A company developed a set of APIs that are being served through the Amazon API Gateway. The API calls need to be authenticated based on OpenID identity providers such as Amazon or Facebook. The APIs should allow access based on a custom authorization model. Which is the simplest and MOST secure design to use to build an authentication and authorization model for the APIs?

Accepted Answer

A)  Use Amazon Cognito user pools and a custom authorizer to authenticate and authorize users based on JSON Web Tokens. 
B)  Build a OpenID token broker with Amazon and Facebook. Users will authenticate with these identify providers and pass the JSON Web Token to the API to authenticate each API call. 
C)  Store user credentials in Amazon DynamoDB and have the application retrieve temporary credentials from AWS STS. Make API calls by passing user credentials to the APIs for authentication and authorization. 
D)  Use Amazon RDS to store user credentials and pass them to the APIs for authentications and authorization.

Question 11

A company needs to secure its existing website running behind an Elastic Load Balancer. The website's Amazon EC2 instances are CPU-constrained. What should be done to secure the website while not increasing the CPU load on the EC2 web servers? (Choose two.)

Accepted Answer

A)  Configure an Elastic Load Balancer with SSL pass-through. 
B)  Configure SSL certificates on an Elastic Load Balancer. 
C)  Configure an Elastic Load Balancer with a Loadable Storage System. 
D)  Install SSL certificates on the EC2 instances. 
E)  Configure an Elastic Load Balancer with SSL termination.

Question 12

A company is building a stock trading application that requires sub-millisecond latency in processing trading requests. Amazon DynamoDB is used to store all the trading data that is used to process each request. After load testing the application, the development team found that due to data retrieval times, the latency requirement is not satisfied. Because of sudden high spikes in the number of requests, DynamoDB read capacity has to be significantly over-provisioned to avoid throttling. What steps should be taken to meet latency requirements and reduce the cost of running the application?

Accepted Answer

A)  Add Global Secondary Indexes for trading data. 
B)  Store trading data in Amazon S3 and use Transfer Acceleration. 
C)  Add retries with exponential back-off for DynamoDB queries 
D)  Use DynamoDB Accelerator to cache trading data.

Question 13

A Developer has an e-commerce API hosted on Amazon ECS. Variable and spiking demand on the application is causing order processing to take too long. The application processes Amazon SQS queues. The ApproximateNumberOfMessagesVisible metric spikes at very high values throughout the day, which cause Amazon CloudWatch alarm breaches. Other ECS metrics for the API containers are well within limits. What can the Developer implement to improve performance while keeping costs low?

Accepted Answer

A)  Target tracking scaling policy 
B)  Docker Swarm 
C)  Service scheduler 
D)  Step scaling policy

Question 14

A Developer created a Lambda function for a web application backend. When testing the Lambda function from the AWS Lambda console, the Developer can see that the function is being executed, but there is no log data being generated in Amazon CloudWatch Logs, even after several minutes. What could cause this situation?

Accepted Answer

A)  The Lambda function does not have any explicit log statements for the log data to send it to CloudWatch Logs. 
B)  The Lambda function is missing CloudWatch Logs as a source trigger to send log data. 
C)  The execution role for the Lambda function is missing permissions to write log data to the CloudWatch Logs. 
D)  The Lambda function is missing a target CloudWatch Log group.

Question 15

A Developer has a stateful web server on-premises that is being migrated to AWS. The Developer must have greater elasticity in the new design. How should the Developer re-factor the application to make it more elastic? (Choose two.)

Accepted Answer

A)  Use pessimistic concurrency on Amazon DynamoDB 
B)  Use Amazon CloudFront with an Auto Scaling group 
C)  Use Amazon CloudFront with an AWS Web Application Firewall 
D)  Store session state data in an Amazon DynamoDB table 
E)  Use an ELB with an Auto Scaling group

Question 16

A developer must ensure that the IAM credentials used by an application in Amazon EC2 are not misused or compromised. What should the developer use to keep user credentials secure?

Accepted Answer

A)  Environment variables 
B)  AWS credentials file 
C)  Instance profile credentials 
D)  Command line options

Question 17

A legacy service has an XML-based SOAP interface. The Developer wants to expose the functionality of the service to external clients with the Amazon API Gateway. Which technique will accomplish this?

Accepted Answer

A)  Create a RESTful API with the API Gateway; transform the incoming JSON into a valid XML message for the SOAP interface using mapping templates. 
B)  Create a RESTful API with the API Gateway; pass the incoming JSON to the SOAP interface through an Application Load Balancer. 
C)  Create a SOAP API with the API Gateway; pass the incoming XML to the SOAP interface through an Application Load Balancer. 
D)  Create a SOAP API with the API Gateway; transform the incoming XML into a valid message for the SOAP interface using mapping templates.

Question 18

What happens, by default, when one of the resources in a CloudFormation stack cannot be created?

Accepted Answer

A)  Previously-created resources are kept but the stack creation terminates. 
B)  Previously-created resources are deleted and the stack creation terminates. 
C)  The stack creation continues, and the final results indicate which steps failed. 
D)  CloudFormation templates are parsed in advance so stack creation is guaranteed to succeed.

Question 19

A company has written a Java AWS Lambda function to be triggered whenever a user uploads an image to an Amazon S3 bucket. The function converts the original image to several different formats and then copies the resulting images to another Amazon S3 bucket. The Developers find that no images are being copied to the second Amazon S3 bucket. They have tested the code on an Amazon EC2 instance with 1GB of RAM, and it takes an average of 500 seconds to complete. What is the MOST likely cause of the problem?

Accepted Answer

A)  The Lambda function has insufficient memory and needs to be increased to 1 GB to match the Amazon EC2 instance 
B)  Files need to be copied to the same Amazon S3 bucket for processing, so the second bucket needs to be deleted. 
C)  Lambda functions have a maximum execution limit of 300 seconds, therefore the function is not completing. 
D)  There is a problem with the Java runtime for Lambda, and the function needs to be converted to node.js.

Question 20

A Development team currently supports an application that uses an in-memory store to save accumulated game results. Individual results are stored in a database. As part of migrating to AWS, the team needs to use automatic scaling. The team knows this will yield inconsistent results. Where should the team store these accumulated game results to BEST allow for consistent results without impacting performance?

Accepted Answer

A)  Amazon S3 
B)  Amazon RDS 
C)  Amazon ElastiCache 
D)  Amazon Kinesis

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