Deployment & Ops Standards

Priority: P1 (OPERATIONAL)

Docker optimization and production deployment standards for NestJS applications.

Docker Optimization

• •Multi-Stage Builds: Mandatory.
  1. •Build Stage: Install devDependencies, build NestJS (nest build).
  2. •Run Stage: Copy only dist and node_modules (pruned), use node:alpine.
• •Security: Do not run as root.
  • •Dockerfile: USER node.

Runtime Tuning (Node.js)

• •Memory Config: Container memory != Node memory.
  • •Rule: Explicitly set Max Old Space.
  • •Command: node --max-old-space-size=XXX dist/main
  • •Calculation: Set to ~75-80% of Kubernetes Limit. (Limit: 1GB -> OldSpace: 800MB).
• •Graceful Shutdown:
  • •Signal: Listen to SIGTERM.
  • •NestJS: app.enableShutdownHooks() is mandatory.
  • •Sleep: Add a "Pre-Stop" sleep in K8s (5-10s) to allow Load Balancer to drain connections before Node process stops accepting traffic.

Init Patterns

• •Database Migrations:
  • •Anti-Pattern: Running migration in main.ts on startup.
  • •Pro Pattern: Use an Init Container in Kubernetes that runs npm run typeorm:migration:run before the app container starts.