A developer needs to migrate an online retail application to AWS to handle an anticipated increase in traffic. The application currently runs on two servers: one server for the web application and another server for the database. The web server renders webpages and manages session state in memory. The database server hosts a MySQL database that contains order details. When traffic to the application is heavy, the memory usage for the web server approaches 100% and the application slows down considerably.
The developer has found that most of the memory increase and performance decrease is related to the load of managing additional user sessions. For the web server migration, the developer will use Amazon EC2 instances with an Auto Scaling group behind an Application Load Balancer.
Which additional set of changes should the developer make to the application to improve the application's performance?
Correct Answer:
B
Using Amazon ElastiCache for Memcached to store and manage the session data will reduce the memory load and improve the performance of the web server. Using Amazon RDS for MySQL DB instance to store the application data will provide a scalable, reliable, and managed database service. Option A is not optimal because it does not address the memory issue of the web server. Option C is not optimal because it does not provide a persistent storage for the application data. Option D is not optimal because it does not provide a high availability and durability for the session data.
References: Amazon ElastiCache, Amazon RDS
A developer is writing an application that will retrieve sensitive data from a third-party system. The application will format the data into a PDF file. The PDF file could be more than 1 MB. The application will encrypt the data to disk by using AWS Key Management Service (AWS KMS). The application will decrypt the file when a user requests to download it. The retrieval and formatting portions of the application are complete.
The developer needs to use the GenerateDataKey API to encrypt the PDF file so that the PDF file can be decrypted later. The developer needs to use an AWS KMS symmetric customer managed key for encryption.
Which solutions will meet these requirements?
plaintext key from the GenerateDataKey API and a symmetric encryption algorithm to encrypt the file.
Correct Answer:
A
✑ The GenerateDataKey API returns a data key that is encrypted under a symmetric encryption KMS key that you specify, and a plaintext copy of the same data
key1. The data key is a random byte string that can be used with any standard encryption algorithm, such as AES or SM42. The plaintext data key can be used to encrypt or decrypt data outside of AWS KMS, while the encrypted data key can be stored with the encrypted data and later decrypted by AWS KMS1.
✑ In this scenario, the developer needs to use the GenerateDataKey API to encrypt
the PDF file so that it can be decrypted later. The developer also needs to use an AWS KMS symmetric customer managed key for encryption. To achieve this, the developer can follow these steps:
A company is using Amazon API Gateway to invoke a new AWS Lambda function The company has Lambda function versions in its PROD and DEV environments. In each environment, there is a Lambda function alias pointing to the corresponding Lambda function version API Gateway has one stage that is configured to point at the PROD alias
The company wants to configure API Gateway to enable the PROD and DEV Lambda function versions to be simultaneously and distinctly available
Which solution will meet these requirements?
Correct Answer:
D
The best solution is to use an API Gateway stage variable to configure the Lambda function alias. This allows you to specify the Lambda function name and its alias or version using the syntax function_name:$ {stageVariables.variable_name} in the Integration Request. You can then create different stages in API Gateway, such as PROD and DEV, and assign different values to the stage variable for each stage. This way, you can invoke different Lambda function versions or aliases based on the stage that you are using, without changing the function name in the Integration Request. References
✑ Using API Gateway stage variables to manage Lambda functions
✑ How to point AWS API gateway stage to specific lambda function alias?
✑ Setting stage variables using the Amazon API Gateway console
✑ Amazon API Gateway stage variables reference
A company is offering APIs as a service over the internet to provide unauthenticated read access to statistical information that is updated daily. The company uses Amazon API Gateway and AWS Lambda to develop the APIs. The service has become popular, and the company wants to enhance the responsiveness of the APIs.
Which action can help the company achieve this goal?
Correct Answer:
A
Amazon API Gateway is a service that enables developers to create, publish, maintain, monitor, and secure APIs at any scale. The developer can enable API caching in API Gateway to cache responses from the backend integration point for a specified time-to- live (TTL) period. This can improve the responsiveness of the APIs by reducing the numberof calls made to the backend service. References:
✑ [What Is Amazon API Gateway? - Amazon API Gateway]
✑ [Enable API Caching to Enhance Responsiveness - Amazon API Gateway]
A company has a web application that runs on Amazon EC2 instances with a custom Amazon Machine Image (AMI) The company uses AWS CloudFormation to provision the application The application runs in the us-east-1 Region, and the company needs to deploy the application to the us-west-1 Region
An attempt to create the AWS CloudFormation stack in us-west-1 fails. An error message states that the AMI ID does not exist. A developer must resolve this error with a solution that uses the least amount of operational overhead
Which solution meets these requirements?
Correct Answer:
B
https://aws.amazon.com/blogs/aws/ec2-ami-copy-between-regions/
