Docker & Container Orchestration for Backend Developers

Containerization ensures environment consistency across development, staging, and production environments.

1. Writing Multi-Stage Dockerfiles

Multi-stage builds keep production Docker images lightweight by compiling dependencies in a builder stage and copying only production binaries to the final runtime image.

# Multi-Stage Node.js Production Dockerfile
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

FROM node:20-alpine AS runner
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/package*.json ./
RUN npm ci --only=production
CMD ["node", "dist/main.js"]

2. Container Health Checks & Lifecycle

Configuring HEALTHCHECK directives allows Docker and Kubernetes to automatically restart unhealthy container instances before traffic drops.

Use non-root users inside Docker containers to follow least-privilege security principles.