Why Dockerfile Best Practices Matter
Poorly written Dockerfiles lead to large, insecure, and hard-to-maintain container images. Following best practices ensures faster builds, smaller images, better security, and improved maintainability.
1. Use Official or Minimal Base Images
Choose minimal or well-maintained base images like:
FROM alpine:3.19
# or
FROM python:3.11-slim
2. Pin Versions Explicitly
Avoid surprises by pinning versions of dependencies and packages:
RUN apt-get install -y curl=7.68.0-1ubuntu2.6
3. Combine RUN Commands
Reduce layers by chaining commands:
RUN apt-get update && apt-get install -y curl unzip && rm -rf /var/lib/apt/lists/*
4. Leverage .dockerignore
Exclude unnecessary files from context to speed up builds and reduce image size:
node_modules
.git
*.log
5. Use Multi-stage Builds
To keep images clean and small:
FROM golang:1.21 as builder
WORKDIR /app
COPY . .
RUN go build -o main
FROM alpine:3.19
COPY --from=builder /app/main /main
CMD ["/main"]
6. Don’t Run as Root
Add a non-root user for security:
RUN addgroup -S app && adduser -S app -G app
USER app
7. Use Healthchecks
Ensure containers are functioning as expected:
HEALTHCHECK CMD curl --fail http://localhost:8080/health || exit 1
8. Clean Up After Yourself
Delete temporary files and unnecessary dependencies:
RUN rm -rf /tmp/*
Conclusion
Following Dockerfile best practices leads to cleaner, safer, and more efficient container images — a must for production environments. Start applying them today to make your containers shine.