AWS Certified Solutions Architect Exam Notes – Lambda

Lambda – Serverless

  • Event-driven computing service. There is no server running. An event comes and the code gets executed.
  • Serverless scales instantly (scales out, not up). If 1 million users hit the same request, 1 million lambdas will run the code.
  • No Servers. No antivirus. No maintenance. No admins. No patching.
  • Supported languages
    • Node.js
    • Java
    • C#
    • Python
    • Go
  • Serverless :
    • DynamoDB
    • Aurora Serverless
    • S3
    • API Gateway
    • Lambda
  • RDS is not Serverless (with exception of Aurora Serverless). They have a server but is managed by AWS.
  • Lambda Timeouts: The default is 3 seconds. Max is 15 minutes
  • Lambda Price: Pay per request and duration of functions
  • AWS Xray: Service that helps you debug complex lambda architectures
  • Triggers: Lambda functions can trigger another Lambda functions


Serverless Architecture 

  • API Gateway (to handle the requests)
  • Lambda functions (auto-scaling)
  • Serverless DB (Dynamo or Aurora Serverless)

Traditional vs Serverless

Traditional

  • ELBs – > EC2 -> RDS
  • Scale with Auto Scaling Groups

Serverless

  • API Gateway -> Lambda -> Dynamo/Aurora Serverless

Serverless Application Model SAM

  • CloudFormation for Serverless. Same scripts with CloudFormation, with some different tags

AWS Step Functions

  • Coordinate multiple AWS services into serverless workflows so you can build and update apps quickly.
  • Coordinate the components of distributed applications and microservices using visual workflows