Overview

• pay per request and compute time

Configuration

• timeout: default 3 seconds, maximum 15 minutes
• Environment variables
• allocated memory (128MB to 3G)
• ability to deploy within a VPC + assign security groups
• IAM execution role must be attached to the Lambda function
• tracing with AWS X-Ray ⇒ enable active tracing will automatically adds X-Ray permission

Concurrency and Throttling

• concurrency up to 1000 executions (can increase through ticket) (standard concurrency)
• can set a "reserved concurrency" at the function level (maximum concurrency that function can reach)
• can set "provisioned concurrency"
• each invocation over the concurrency limit will trigger a "Throttle"
• Throttle behavior:

  • if synchronous invocation ⇒ return ThrottleError - 429 (eg: http request)

  • If asynchronous invocation ⇒ retry automatically twice and after all retries, then go to DLQ (eg: S3 trigger)

    • DLQ can be a SNS topic or SQS queue

    ⇒ debug in production

Limitation

• Execution:
  • Memory allocation: 128MB - 3008MB
  • Maximum execution time: 15 minutes
  • Disk capacity (in /tmp): 512MB
  • Concurrency limits: 1000
• Deployment:
  • install the dependencies packages and zip with code
    • libraries need to be compiled on Amazon Linux
  • Lambda function deployment size (compressed): 50MB
    • if > 50MB, use S3
  • Uncompressed deployment: 250MB
  • can use /tmp directory to load other file at startup
  • size of environment variables: 4KB

Versions vs Aliases