Optimizing Docker Images for Production

Container optimization is a crucial skill for any Cloud Engineer. Large images slow down deployments, increase storage costs, and broaden the attack surface.

The Problem: Bloated Images

A standard Node.js image (node:18) can be over 1GB. For a simple Hello World app, this is unacceptable.

Solution 1: Use Alpine

Switching to node:18-alpine immediately drops the base size to under 50MB.

FROM node:18-alpine
WORKDIR /app
COPY . .
CMD ["node", "index.js"]

Solution 2: Multi-Stage Builds

The real magic happens with multi-stage builds. You use one stage to install dependencies and build, and a second empty stage to run the app.

# Build Stage
FROM node:18-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Production Stage
FROM node:18-alpine
WORKDIR /app
COPY --from=builder /app/.next ./.next
COPY --from=builder /app/public ./public
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./package.json

CMD ["npm", "start"]

Result

By implementing these techniques, I've seen production images drop from 1.2GB to 120MB. Faster deployments, happier DevOps.