Certified Developer Associate 2019 -- 1

A Developer is building a web application that uses Amazon API Gateway to expose an AWS Lambda function to process requests from clients. During testing, the Developer notices that the API Gateway times out even though the Lambda function finishes under the set time limit.
Which of the following API Gateway metrics in Amazon CloudWatch can help the Developer troubleshoot the issue? (Choose two.)

  • A. CacheHitCount
  • B. IntegrationLatency
  • C. CacheMissCount
  • D. Latency
  • E. Count AD
B、C
 
An AWS Lambda function must access an external site by using a regularly rotated user name and password. These items must be kept securely and cannot be stored in the function code. What combination of AWS services can be used to accomplish this? (Choose two.)
  • A. AWS Certificate Manager (ACM)
  • B. AWS Systems Manager Parameter Store
  • C. AWS Trusted Advisor
  • D. AWS KMS
  • E. Amazon GuardDuty
B、D
 
A Developer is trying to deploy a serverless application using AWS CodeDeploy. The application was updated and needs to be redeployed. What file does the Developer need to update to push that change through CodeDeploy?
  • A. dockerrun.aws.json  ## EB用于管理多docker环境
  • B. buildspec.yml  ## CodeBuild 用于编译代码
  • C. appspec.yml   ## 应用描述文件
  • D. ebextensions.config

application specification file (AppSpec file) 是 YAML 格式或 JSON 格式文件,由 CodeDeploy 用来管理部署。

注意: EC2/本地 部署的 AppSpec file 的名称必须为 appspec.yml。Amazon ECS 或 AWS Lambda 部署的 AppSpec file 的名称必须为 appspec.yaml。

 

A Developer wants to upload data to Amazon S3 and must encrypt the data in transit. Which of the following solutions will accomplish this task? (Choose two.)

  • A. Set up hardware VPN tunnels to a VPC and access S3 through a VPC endpoint
  • B. Set up Client-Side Encryption with an AWS KMS-Managed Customer Master Key
  • C. Set up Server-Side Encryption with AWS KMS-Managed Keys
  • D. Transfer the data over an SSL connection
  • E. Set up Server-Side Encryption with S3-Managed Keys

A company is running a Docker application on Amazon ECS. The application must scale based on user load in the last 15 seconds.
How should a Developer instrument the code so that the requirement can be met?

  • A. Create a high-resolution custom Amazon CloudWatch metric for user activity data, then publish data every 30 seconds
  • B. Create a high-resolution custom Amazon CloudWatch metric for user activity data, then publish data every 5 seconds
  • C. Create a standard-resolution custom Amazon CloudWatch metric for user activity data, then publish data every 30 seconds
  • D. Create a standard-resolution custom Amazon CloudWatch metric for user activity data, then publish data every 5 seconds

A company needs to ingest terabytes of data each hour from thousands of sources that are delivered almost continually throughout the day. The volume of messages generated varies over the course of the day. Messages must be delivered in real time for fraud detection and live operational dashboards.
Which approach will meet these requirements?

  • A. Send the messages to an Amazon SQS queue, then process the messages by using a fleet of Amazon EC2 instances
  • B. Use the Amazon S3 API to write messages to an S3 bucket, then process the messages by using Amazon Redshift
  • C. Use AWS Data Pipeline to automate the movement and transformation of data
  • D. Use Amazon Kinesis Data Streams with Kinesis Client Library to ingest and deliver messages

A Developer has been asked to create an AWS Lambda function that is triggered any time updates are made to items in an Amazon DynamoDB table. The function has been created, and appropriate permissions have been added to the Lambda execution role. Amazon DynamoDB streams have been enabled for the table, but the function is still not being triggered.
Which option would enable DynamoDB table updates to trigger the Lambda function?

  • A. Change the StreamViewType parameter value to NEW_AND_OLD_IMAGES for the DynamoDB table
  • B. Configure event source mapping for the Lambda function
  • C. Map an Amazon SNS topic to the DynamoDB streams
  • D. increase the maximum execution time (timeout) setting of the Lambda function

 

A Developer is building a three-tier web application that should be able to handle a minimum of 5000 requests per minute. Requirements state that the web tier should be completely stateless while the application maintains session state for the users.
How can session data be externalized, keeping latency at the LOWEST possible value?

  • A. Create an Amazon RDS instance, then implement session handling at the application level to leverage a database inside the RDS database instance for session data storage
  • B. Implement a shared file system solution across the underlying Amazon EC2 instances, then implement session handling at the application level to leverage the shared file system for session data storage
  • C. Create an Amazon ElastiCache Memcached cluster, then implement session handling at the application level to leverage the cluster for session data storage
  • D. Create an Amazon DynamoDB table, then implement session handling at the application level to leverage the table for session data storage

An Amazon DynamoDB table uses a Global Secondary Index (GSI) to support read queries. The primary table is write-heavy, whereas the GSI is used for read operations. Looking at Amazon CloudWatch metrics, the Developer notices that write operations to the primary table are throttled frequently under heavy write activity. However, write capacity units to the primary table are available and not fully consumed.
Why is the table being throttled?

  • A. The GSI write capacity units are underprovisioned
  • B. There are not enough read capacity units on the primary table
  • C. Amazon DynamoDB Streams is not enabled on the table
  • D. A large write operation is being performed against another table

 

A company runs an e-commerce website that uses Amazon DynamoDB where pricing for items is dynamically updated in real time. At any given time, multiple updates may occur simultaneously for pricing information on a particular product. This is causing the original editor's changes to be overwritten without a proper review process.
Which DynamoDB write option should be selected to prevent this overwriting?

  • A. Concurrent writes
  • B. Conditional writes
  • C. Atomic writes
  • D. Batch writes B

 

A company needs a version control system for collaborative software development. Features of the system must include the following:
Support for batches of changes across multiple files
Parallel branching
Version tracking
Which AWS service will meet these requirements?

  • A. AWS CodePipeline
  • B. Amazon S3
  • C. AWS Code Build
  • D. AWS CodeCommit 

A company is using continuous integration and continuous delivery systems. A Developer now needs to automate a software package deployment to both
Amazon EC2 instances and virtual servers running on-premises.
Which AWS service should be used to accomplish this?

  • A. AWS CodePipeline
  • B. AWS CodeBuild
  • C. AWS Elastic Beanstalk
  • D. AWS CodeDeploy

A Developer created a new AWS account and must create a scalable AWS Lambda function that meets the following requirements for concurrent execution:
Average execution time of 100 seconds
50 requests per second
Which step must be taken prior to deployment to prevent errors?

  • A. Implement dead-letter queues to capture invocation errors
  • B. Add an event source from Amazon API Gateway to the Lambda function
  • C. Implement error handling within the application code
  • D. Contact AWS Support to increase the concurrent execution limits

 

A Development team wants to instrument their code to provide more detailed information to AWS X-Ray than simple outgoing and incoming requests. This will generate large amounts of data, so the Development team wants to implement indexing so they can filter the data.
What should the Development team do to achieve this?

  • A. Add annotations to the segment document and the code
  • B. Add metadata to the segment document and the code
  • C. Configure the necessary X-Ray environment variables
  • D. Install required plugins for the appropriate AWS SDK
  • https://docs.aws.amazon.com/zh_cn/xray/latest/devguide/xray-concepts.html

 

A team of Developers must migrate an application running inside an AWS Elastic Beanstalk environment from a Classic Load Balancer to an Application Load
Balancer.
Which steps should be taken to accomplish the task using the AWS Management Console?

  • A. 1. Update the application code in the existing deployment. 2. Select a new load balancer type before running the deployment. 3. Deploy the new version of the application code to the environment.
  • B. 1. Create a new environment with the same configurations except for the load balancer type. 2. Deploy the same application version as used in the original environment. 3. Run the swap-environment-cnames action.
  • C. 1. Clone the existing environment, changing the associated load balancer type. 2. Deploy the same application version as used in the original environment. 3. Run the swap-environment-cnames action.
  • D. 1. Edit the environment definitions in the existing deployment. 2. Change the associated load balancer type according to the requirements. 3. Rebuild the environment with the new load balancer type.
您只能在创建环境期间选择您的环境使用的负载均衡器类型。您可以更改设置以管理运行的环境的负载均衡器行为,但 不能更改其类型。与 传统负载均衡器 或网络负载均衡器不同,应用程序负载均衡器 不能具有传输层(第 4 层)TCP 或 SSL/TLS 侦听器。它仅支持 HTTP 和 HTTPS 侦听器。此外,它不能使用后端身份验证对负载均衡器和后端实例之间的 HTTPS 连接进行身份验证。

 A Developer must encrypt a 100-GB object using AWS KMS.  What is the BEST approach?

  • A. Make an Encrypt API call to encrypt the plaintext data as ciphertext using a customer master key (CMK)
  • B. Make an Encrypt API call to encrypt the plaintext data as ciphertext using a customer master key (CMK) with imported key material
  • C. Make an GenerateDataKey API call that returns a plaintext key and an encrypted copy of a data key. Use a plaintext key to encrypt the data
  • D. Make an GenerateDataKeyWithoutPlaintext API call that returns an encrypted copy of a data key. Use an encrypted key to encrypt the data 

A Development team would like to migrate their existing application code from a GitHub repository to AWS CodeCommit.
What needs to be created before they can migrate a cloned repository to CodeCommit over HTTPS?

  • A. A GitHub secure authentication token
  • B. A public and private SSH key file
  • C. A set of Git credentials generated from IAM
  • D. An Amazon EC2 IAM role with CodeCommit permissions
https://docs.aws.amazon.com/zh_cn/codecommit/latest/userguide/how-to-migrate-repository-existing.html

 

A Developer is writing a REST service that will add items to a shopping list. The service is built on Amazon API Gateway with AWS Lambda integrations. The shopping list items are send as query string parameters in the method request.
How should the Developer convert the query string parameters to arguments for the Lambda function?

  • A. Enable request validation
  • B. Include the Amazon Resource Name (ARN) of the Lambda function
  • C. Change the integration type
  • D. Create a mapping template 
https://docs.aws.amazon.com/zh_cn/apigateway/latest/developerguide/api-gateway-create-api-step-by-step.html#getting-started-mappings

 

When developing an AWS Lambda function that processes Amazon Kinesis Data Streams, Administrators within the company must receive a notice that includes the processed data.
How should the Developer write the function to send processed data to the Administrators?

  • A. Separate the Lambda handler from the core logic
  • B. Use Amazon CloudWatch Events to send the processed data
  • C. Publish the processed data to an Amazon SNS topic
  • D. Push the processed data to Amazon SQS

 

A Developer is storing documents in Amazon S3 that will require encryption at rest. The encryption keys must be rotated annually, at least.
What is the easiest way to achieve this?

  • A. Encrypt the data before sending it to Amazon S3
  • B. Import a custom key into AWS KMS with annual rotation enabled
  • C. Use AWS KMS with automatic key rotation
  • D. Export a key from AWS KMS to encrypt the data

 

 

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