AWS certificate memo DVA 笔记

337, 342, 345, 374, 378, 412, 416, 418, 439, 444, 476, 490, 499

KMS stores the CMK, and receives data from the client, which it encrypts and send it back

UDP stands for User Datagram Protocol. UDP is used when speed is desirable and error correction is not necessary. For example, UDP is frequently used for live broadcasts and online games.

 "X-Ray sampling": X-Ray SDK applies a sampling algorithm to determine which requests get traced however because our application is failing to send data to X-Ray it does not help in determining the cause of failure.
 
 "Use the Encryption SDK": The AWS Encryption SDK is an encryption library that helps make it easier for you to implement encryption best practices in your application.
 
 use the ChangeMessageVisibility API to extend their message timeout and process the message until the end while making sure other consumers won't see that message.
 SQS "Use Long Polling" - Eliminates the number of empty responses
 
Rolling with additional batches is the most optimum deployment policy when a user doesn't want to compromise on the output capacity of the application but also keep the additional expense incurs to the minimum.
Immutable creates a full deployment including a copy of all the resources (with new versions if applied) in a new Autoscaling group. Therefore, for the time the rolling is going on you pay 2 times the normal price because you have everything doubled.
"blue/green" - This will work by creating an entirely new environment

API Gateway lets you use mapping templates to map the payload from a method request to the corresponding integration request and an integration response to the corresponding method response.

Some applications might need to perform many kinds of queries, using a variety of different attributes other than the specified partition key as query criteria. To support these requirements, you can create one or more global secondary indexes and issue Query requests against these indexes.

"Stage Variables" - They act like environment variables and can be used in your API setup
Lambda Aliases allow you to create a "mutable" Lambda version that points to whatever version you want in the backend.

The intrinsic function Ref returns the value of the specified parameter or resource. 
!GetAtt - A function returns the value of an attribute from a resource in the template

web identity federation: Use of an identity provider like Google or Facebook to exchange for temporary AWS security credentials.

SSE-S3, SSE-KMS, SSE-C, client side encryption：https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingEncryption.html