How Amazon Lambda Works 🔥

Executive Summary

AWS Lambda is a serverless computing service that enables scalable application development without server management. It uses microVMs for isolation, Firecracker for lightweight virtualization, and optimizes performance through warm starts and lazy-loaded container images. The architecture includes invoke, assignment, and worker services to handle requests efficiently.

Core Technical Concepts/Technologies

• Serverless Computing: No server provisioning or management.
• MicroVMs: Lightweight VMs for tenant isolation (via Firecracker).
• Warm/Cold Starts: Reusing microVMs (warm) vs. initializing new ones (cold).
• Lambda Services: Invoke (request routing), Assignment (worker tracking), Worker (execution).
• Optimizations: SnapStart (microVM snapshots), lazy-loaded container images.

Main Points

• Scalability:
  • Functions run on distributed workers across availability zones.
  • Assignment service tracks workers using a fault-tolerant journal log.
• Performance:
  • Uses EC2 workers with Firecracker-managed microVMs for isolation.
  • Placement service leases/monitors workers dynamically.
• Latency Reduction:
  • Warm starts reuse microVMs; cold starts use SnapStart (90% faster).
  • Container images are lazy-loaded (only necessary chunks fetched).

Technical Specifications & Implementation

• Firecracker: Virtualization manager for microVMs.
• SnapStart: MicroVM snapshots reduce cold-start latency.
• Lazy Loading: Container image chunks downloaded on-demand (Slacker paper).

Key Takeaways

1. Serverless Efficiency: Eliminates server management, scales automatically.
2. Isolation: MicroVMs ensure security without resource waste.
3. Latency Optimization: Warm starts and SnapStart minimize delays.
4. Cost Savings: Pay-per-use model avoids idle resource costs.

Limitations/Caveats

• Cold starts can still impact latency for new invocations.
• Research-based insights may differ from actual AWS implementation.
• Container image optimization requires careful layer management.