Distroless vs Alpine: Choosing Secure Container Images with Code Examples

When building secure containers, the base image plays a crucial role. Using large, bloated images can introduce security risks, unnecessary dependencies, and a larger attack surface. That’s where Distroless and Alpine come in.

By the end of this guide, you’ll understand:
✅ What Distroless and Alpine are, and their history
✅ When to use Distroless vs Alpine
✅ How to build secure containers with both
✅ Best practices for reducing attack surfaces

Let’s lock things down! 🔐

1. What Are Distroless and Alpine?

1.1 What is Distroless?

Distroless is a minimal container base image developed by Google.

• 🏗 No package manager (APT/YUM) or shell
• 🔒 Only includes runtime dependencies
• 📉 Smaller attack surface
• 🚀 Ideal for production workloads

1.2 What is Alpine?

Alpine Linux is a lightweight Linux distribution designed for security and efficiency.

• 🏗 Tiny (5 MB) Linux-based distribution
• 🔄 Uses musl and busybox instead of glibc
• 🔥 Includes package manager (apk)
• 💡 Best for lightweight, flexible containers

2. History of Distroless and Alpine

When to Use One Over the Other?

Now, let’s build secure containers using Distroless and Alpine.

3. Building Secure Containers with Distroless

Distroless removes everything except what’s needed.

Step 1: Create a Simple Go App

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package main

import "fmt"

func main() {
    fmt.Println("Hello, Secure World!")
}

Step 2: Build a Secure Dockerfile with Distroless

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# Use a multi-stage build
FROM golang:1.18 AS builder
WORKDIR /app
COPY main.go .
RUN go build -o main

# Use Distroless for production
FROM gcr.io/distroless/base
COPY --from=builder /app/main /main
CMD ["/main"]

Step 3: Build and Run

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docker build -t my-distroless-app .
docker run --rm my-distroless-app

Why Distroless?

• ❌ No unnecessary tools
• 🔒 No package manager (lower attack surface)
• ⚡ Optimized for production

4. Building Secure Containers with Alpine

Alpine is lightweight, but still has a package manager.

Step 1: Create a Dockerfile with Alpine

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FROM alpine:latest
RUN apk add --no-cache bash curl
CMD ["sh", "-c", "echo Hello from Alpine!"]

Step 2: Build and Run

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docker build -t my-alpine-app .
docker run --rm my-alpine-app

Why Alpine?

• ✅ Lightweight (~5MB)
• ✅ Faster builds with package manager (apk)
• ✅ Easier debugging with built-in shell

5. Comparing Distroless vs Alpine in Real-World Scenarios

6. Best Practices for Secure Containers

✅ Use multi-stage builds to remove unnecessary dependencies
✅ Use scratch or distroless for minimal images
✅ Scan images for vulnerabilities with Trivy

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trivy image my-distroless-app

✅ Use non-root users for containers

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RUN addgroup -S appgroup && adduser -S appuser -G appgroup
USER appuser

✅ Set CMD and ENTRYPOINT explicitly

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CMD ["/app"]

Final Thoughts

Both Distroless and Alpine help build secure, minimal containers, but they serve different use cases.

Key Takeaways

✅ Use Distroless for minimal, production-ready images
✅ Use Alpine for lightweight, flexible containers with a package manager
✅ Distroless has no shell, making it harder to attack
✅ Alpine is great for debugging and lightweight applications
✅ Reduce attack surfaces by removing unnecessary dependencies

Choosing between Distroless vs Alpine depends on your security needs, debugging requirements, and deployment environment. 🚀

Reference Links

• Distroless Official Repo
• Alpine Linux Official Site
• Kubernetes Security Guide
• Docker Best Practices