Intermediate

One Dockerfile, multiple environments. Use target to build only the stage you need - faster builds, smaller images, cleaner separation. The basics Multi-stage Dockerfile: # Development stage FROM node:20-alpine AS development WORKDIR /app COPY package*.json ./ RUN npm install COPY . . CMD ["npm", "run", "dev"] # Production stage FROM node:20-alpine AS production WORKDIR /app COPY package*.json ./ RUN npm ci --only=production COPY . . RUN npm run build CMD ["npm", "start"] Target specific stages in compose.yml: ...

Stop manually restarting containers when code changes. Docker Compose Watch automatically syncs files and reloads services - zero interruption development. The basics Enable watch mode with: docker compose up --watch # If you don't want mixed logs, you can run it in a dedicated process, you need to have your stack started on its own process docker compose watch Then configure watching in your compose.yml: services: web: image: node:20 command: npm start develop: watch: - path: ./src target: /app/src action: sync - path: package.json action: rebuild Files in ./src sync instantly. Changes to package.json trigger a rebuild. ...

Zombie processes in your containers? Slow shutdowns? Your app shouldn’t run as PID 1. Here’s the simple fix. The problem When your app runs as PID 1, it has special responsibilities: Handle system signals (SIGTERM, SIGINT) Reap zombie processes Forward signals to child processes Most apps (especially Node.js, Python) don’t handle these well. The solution Add init: true to your service: services: app: image: node:20 init: true # Adds Tini as PID 1 command: node server.js Docker automatically injects a tiny init system (Tini) that handles PID 1 responsibilities properly. ...

Package your entire Docker Compose application as an OCI artifact and share it through any container registry. No more complex installation instructions. The basics Publish your Compose configuration as an OCI artifact: # Publish your compose.yml to a registry docker compose publish myusername/myapp:v1.0 # Users run it directly with oci:// prefix docker compose -f oci://docker.io/myusername/myapp:v1.0 up The compose.yml (and any included files) are stored as an OCI artifact alongside your container images. ...

Stop doing docker compose down && docker compose up for every code change. Docker Compose lets you restart individual services while keeping the rest running. The solution Restart just what changed: # Restart only the web service docker compose up -d web # Your database, cache, and queue keep running! This simple command saves minutes per restart. Your database keeps its data, Redis maintains its cache, message queues preserve their state. ...