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AWS - Serverless Architectures

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• AWS - Serverless Architectures
  • Mobile application: MyTodoList
  • Serverless hosted website: MyBlog.com
  • Micro Services architecture
  • Software updates offloading

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Mobile application: MyTodoList

• Requirement: We want to create a mobile application with the following requirements
  • Expose as REST API with HTTPS (API Gateway)
  • Serverless architecture
  • Users should be able to directly interact with their own folder in S3 (S3)
  • Users should authenticate through a managed serverless service (Conigto)
  • The users can write and read to-dos, but they mostly read them (DAX)
  • The database should scale, and have some high read throughput (Dynamo)

• Summary:
  • Serverless REST API: HTTPS, API Gateway, Lambda, DynamoDB
  • Using Cognito to generate temporary credentials with STS to access S3 bucket with restricted policy. App users can directly access AWS resources this way. Pattern can be applied to DynamoDB, Lambda…
  • Caching the reads on DynamoDB using DAX
  • Caching the REST requests at the API Gateway level
  • Security for authentication and authorization with Cognito, STS(Security token service)

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Serverless hosted website: MyBlog.com

• Requirement:

  • This website should scale globally (CloudeFront)
  • Blogs are rarely written, but often read
  • Some of the website is purely static files, the rest is a dynamic REST API (S3 static web host, API gateway)
  • Caching must be implement where possible (API Gateway cached response)
  • Any new users that subscribes should receive a welcome email (DynamoDB, lambda)
  • Any photo uploaded to the blog should have a thumbnail generated (S3, lambda)

• Serving static content, globally, securely

• a public serverless REST API + DynamoDB Global Tables

• Welcome email flow

• Thumbnail Generation flow

• Summary
  • We’ve seen static content being distributed using CloudFront with S3
  • The REST API was serverless, didn’t need Cognito because public
  • We leveraged a Global DynamoDB table to serve the data globally
  • (we could have used Aurora Global Database)
  • We enabled DynamoDB streams to trigger a Lambda function
  • The lambda function had an IAM role which could use SES
  • SES (Simple Email Service) was used to send emails in a serverless way
  • S3 can trigger SQS / SNS / Lambda to notify of events

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Micro Services architecture

• Requirement:
  • Many services interact with each other directly using a REST API
  • Each architecture for each micro service may vary in form and shape
  • We want a micro-service architecture so we can have a leaner development lifecycle for each service

• Summary:

  • You are free to design each micro-service the way you want
  • Patterns:
    • Synchronous patterns: API Gateway, Load Balancers
    • Asynchronous patterns: SQS, Kinesis, SNS, Lambda triggers (S3)

• Challenges with micro-services:

  • repeated overhead for creating each new microservice,
  • issues with optimizing server density/utilization
  • complexity of running multiple versions of multiple microservices simultaneously
  • proliferation of client-side code requirements to integrate with many separate services.

• Some of the challenges are solved by Serverless patterns:

  • API Gateway, Lambda scale automatically and you pay per usage
  • You can easily clone API, reproduce environments
  • Generated client SDK through Swagger integration for the API Gateway

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Software updates offloading

• Req:

  • We have an application running on EC2, that distributes software updates once in a while
  • When a new software update is out, we get a lot of request and the content is distributed in mass over the network. It’s very costly
  • We don’t want to change our application, but want to optimize our cost and CPU, how can we do it?

• current state

• Solution

• Why CloudFront?

  • No changes to architecture
  • Will cache software update files at the edge
  • Software update files are not dynamic, they’re static (never changing)
  • Our EC2 instances aren’t serverless
  • But CloudFront is, and will scale for us
  • Our ASG will not scale as much, and we’ll save tremendously in EC2
  • We’ll also save in availability, network bandwidth cost, etc
  • Easy way to make an existing application more scalable and cheaper!

• 注:

  • 需求意思是 ec2 负责分发软件更新, 当新版本更新需要分发时,有巨量请求, 造成 ASG 自动 scale, 提高费用
  • 解决方法, 使用 CloudFront.
    • 软件更新是静态
    • cloudfront is serverless
    • cloudfront is auto scaling, 无需 asg, 即无需增加费用.
    • 添加 cloudfront 无需修改现架构.

• Sample:

  • You are running a photo-sharing website where your images are downloaded from all over the world. Every month you publish a master pack of beautiful mountain images that are over 15 GB in size. The content is currently hosted on an Elastic File System (EFS) file system and distributed by an Application Load Balancer and a set of EC2 instances. Each month, you are experiencing very high traffic which increases the load on your EC2 instances and increases network costs. What do you recommend to reduce EC2 load and network costs without refactoring your website?
    • Amazon CloudFront is a fast content delivery network (CDN) service that securely delivers data, videos, applications, and APIs to customers globally with low latency, high transfer speeds. Amazon CloudFront can be used in front of an Application Load Balancer.

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