AWS Lambda

What is a Serverless Architecture

• Is a way to build and run applications and services without having to manage infrastructure and scale, maintain servers.
• Your application still runs on servers, but all the server management is done by AWS
• AWS offers technologies for running code, managing data, and integrating applications, all without managing servers
• It feature automatic scaling, built-in high availability, and a pay-for-use billing model to increase agility and optimize costs.
• Serverless applications start with AWS Lambda, natively integrated with over 200 AWS services and software as a service (SaaS) applications
• Serverless does not mean there are no servers. it means you just don’t manage / provision / see them.

Serverless Services in AWS

• AWS Lambda
• AWS Fargate
• DynamoDB
• AWS Cognito
• AWS API Gateway
• Amazon S3
• AWS SNS & SQS
• AWS Kinesis Data Firehose
• Aurora Serverless
• Step Functions

What is AWS Lambda

• Lambda is a compute service that lets you run code without provisioning or managing servers.
• Lambda runs your code on a high-availability compute infrastructure.
• AWS performs all of the administration of the compute resources, including server and operating system maintenance, capacity provisioning and automatic scaling, code monitoring and logging
• you can run code for virtually any type of application or backend service
• AWS Lambda runs your code on a high-availability compute infrastructure
• AWS Lambda executes your code only when needed and scales automatically.
• You pay only for the compute time you consume – No charge when your code is not running.

EC2 Instance	AWS Lambda
Virtual Servers in the Cloud	Virtual functions – no servers to manage!
Limited by RAM and CPU	Limited by time – short executions
Continuously running	Run on-demand
Scaling means: To add or remove servers	Scaling is automated!

Benefits of AWS Lambda

• Easy Pricing
  • Pay per request and compute time
  • Free tier of 1,000,000 AWS Lambda requests and 400,000 GBs of compute time
• No servers to manage
• Continuous scaling
• Integrated with the many AWS services
• Integrated with many programming languages
• Easy monitoring through AWS CloudWatch
• Easy to get more resources per functions
• Increasing RAM will also improve CPU and network!

AWS Lambda language support

• Node.js
• Python
• Java (Java 8 compatible)
• C# (.NET Core/ Powershell)
• Golang
• Ruby
• Custom Runtime API

AWS Lambda Functions Configuration

• IAM role (execution role)
  • This is the role that AWS Lambda assumes when it executes the Lambda function on your behalf.
• Handler name
  • The handler refers to the method in your code where AWS Lambda begins execution.
  • AWS Lambda passes any event information, which triggered the invocation, as a parameter to the handler method.
• Language Selection
• Write your source code

Lambda Function – Services it can access

• Lambda functions can access
  • AWS Services running in AWS VPCs (Ex. Redshift , ElastiCache, RDS instances)
  • Non-AWS Services running on EC2 instances in an AWS VPC
• Additional configuration will be required for VPC access (Security group and subnet IDs)
• AWS Lambda runs your function code securely within an internal AWS VPC (not your VPC) by default.
  • This VPC has connectivity to AWS services and the internet.
  • You can configure a lambda function to connect to private subnets (DBs, Cache instances, or Internal services) in your VPC in your accounts
• To enable your Lambda function to access resources inside your VPC:
  • Provide additional VPC-specific configuration information that includes VPC subnet IDs and security group IDs
  • Lambda will then create an ENI for each subnet and security group attached to the Lambda function

Invoking Lambda Functions

• On-demand Lambda function invocation
  • Amazon API Gateway
  • Load Balancer
  • Web/Mobile application
  • Using SDKs
• Scheduled events
  • Regular, scheduled basis.
  • Cron Jobs
• Event Source Mapping
  • An event source is the AWS service or custom application that publishes events,
  • A Lambda function is the custom code that processes the events.
  • Event sources publish events that cause the Lambda function to be invoked

Supported AWS event sources

• Amazon S3
• Amazon DynamoDB
• Amazon Kinesis Streams
• Amazon Simple Notification Service
• Amazon Simple Email Service
• Amazon Cognito
• AWS CloudFormation
• Amazon CloudWatch Logs
• Amazon CloudWatch Events
• AWS CodeCommit
• AWS Config
• Amazon Alexa
• Amazon Lex
• Amazon API Gateway
• AWS IoT Button
• Amazon CloudFront
• Amazon Kinesis Firehose
• Amazon SQS

Use Cases of AWS Lambda

• You have a photo sharing application. Your application upload photos, and the application stores these user photos in an Amazon S3 bucket.
• Lambda function triggers for each photo upload and resize it for web. Mobile and tab size

AWS Lambda Limits

• Execution
  • Memory allocation: 128 MB – 3008 MB (64 MB increments)
  • Maximum execution time: 900 seconds (15 minutes)
  • Environment variables (4 KB)
  • Concurrency executions: 1000 (can be increased)
• Deployment
  • Lambda function deployment size (compressed .zip): 50 MB
  • Size of uncompressed deployment (code + dependencies): 250 MB
  • Can use the /tmp directory to load other files at startup
  • Size of environment variables: 4 KB

Monitoring and Pricing

• AWS Lambda automatically monitors Lambda functions on your behalf, reporting metrics through Amazon CloudWatch
• Log Captured in CloudWatch in Log Group
• Pricing: https://aws.amazon.com/lambda/pricing/