AWS - Linux Alpine images

Using Alpine Linux as the operating system layer of your Docker image instead of a full Linux distro like Ubuntu or Debian.

It is not AWS-specific — but it is very popular on AWS because of performance and cost benefits.

“Alpine base images on AWS reduce container size, improve startup time, lower ECR costs, and reduce vulnerabilities, but require compatibility testing due to musl vs glibc differences.”

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What is Alpine Linux?

Alpine Linux is a very small, security-focused Linux distribution.

Typical sizes:

Base Image	Approx Size
Ubuntu	70–120 MB
Debian	60–100 MB
Alpine	5–15 MB

So your container becomes much smaller.

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Example in Dockerfile (.NET)

Normal:

FROM mcr.microsoft.com/dotnet/aspnet:8.0

Alpine:

FROM mcr.microsoft.com/dotnet/aspnet:8.0-alpine

Sample Alpine Docker file

FROM mcr.microsoft.com/dotnet/aspnet:8.0-alpine

WORKDIR /app

COPY --from=build /app/out .

ENTRYPOINT ["dotnet", "MyApp.dll"]

Difference:

• Same .NET runtime
• Smaller OS layer

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Why It Matters on AWS

1. Faster Image Pull (ECR → ECS/EKS/Lambda)

Smaller image = faster download.

Example:

• Ubuntu image: 400 MB → 15–20 sec pull
• Alpine image: 90 MB → 3–5 sec pull

This directly impacts:

• Lambda cold start
• ECS task startup
• Auto-scaling speed

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2. Lower Storage Cost (ECR)

AWS ECR charges for storage.

Smaller image:

• Less GB stored
• Lower monthly cost

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3. Better Security

Alpine includes:

• Fewer packages
• Smaller attack surface
• Fewer CVEs

Security scans (ECR / Trivy) usually show less vulnerabilities.

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4. Faster CI/CD Pipelines

In CodeBuild / GitHub Actions:

• Faster build
• Faster push/pull
• Less network usage

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Where You Use It on AWS

AWS Service	Benefit
ECS Fargate	Faster container start
EKS (Kubernetes)	Faster pod scheduling
Lambda Container	Reduced cold start
CodeBuild	Faster pipelines
ECR	Lower storage cost

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Important Caveat (Very Important)

Alpine uses musl libc instead of glibc.

Some libraries or native dependencies may fail, especially:

• Image processing libs
• Oracle drivers
• Some older .NET native packages
• Python scientific libs

If your app depends on native binaries, test carefully.

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When NOT to Use Alpine

Avoid Alpine if:

• You need heavy native libraries
• You see runtime crashes related to libc
• Vendor software requires glibc
• You need full debugging tools

In such cases use:

• -slim images
• Debian slim
• Ubuntu minimal

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