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.