Why should you care?

Same image runs on laptop, CI, and Kubernetes — eliminates dependency drift.

See it live — copy this example

Paste into your MeanVerse project (Angular + Express + MongoDB), then run with ng serve / node / mongosh as noted.

# api/Dockerfile
FROM node:20-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

FROM node:20-alpine
WORKDIR /app
ENV NODE_ENV=production
COPY --from=build /app/dist ./dist
COPY --from=build /app/node_modules ./node_modules
EXPOSE 3000
CMD ["node", "dist/server.js"]

What happened?

• Multi-stage build compiles TS in build stage.
• Final image only has production artifacts — smaller and safer.
• node:20-alpine reduces attack surface.

Practice next

1. Write Dockerfile for api with multi-stage.
2. Add .dockerignore for node_modules.
3. docker build -t meanverse-api:local .
4. Add HEALTHCHECK CMD curl -f http://localhost:3000/health
5. Scan image with trivy meanverse-api:local.

Remember

Docker image = app + runtime frozen. Multi-stage keeps images lean. Foundation for Compose and K8s.

Consistent staging

Bug reproduced only in prod Node patch level.

Outcome: Docker pins node:20-alpine; dev matches prod exactly.