.NET Dockerfile Generator

Generate production-ready multi-stage Dockerfiles for .NET applications.

Workflow

Determine .NET version (8, 9, or 10) from project file or ask user
Identify project type: ASP.NET Core web app, API, worker service, or console app
Locate project file path (e.g.,
```
src/MyApp/MyApp.csproj
```
)
Choose optimization: standard, chiseled (smaller), or native AOT (smallest/fastest startup)

Breaking Change in .NET 10: Ubuntu is now the default Linux distribution for all .NET container images. Debian images are no longer provided. Tags like
10.0
,
10.0-noble
, and
10.0-noble-chiseled
all use Ubuntu 24.04 "Noble Numbat".

Image Selection Guide

Scenario	Runtime Image	Compressed Size
Standard ASP.NET	`aspnet:10.0`	~92 MB
Smaller footprint	`aspnet:10.0-alpine`	~52 MB
Production (recommended)	`aspnet:10.0-noble-chiseled`	~53 MB
Azure Linux distroless	`aspnet:10.0-azurelinux3.0-distroless`	~55 MB
Self-contained	`runtime-deps:10.0-noble-chiseled`	~22 MB
Native AOT	`runtime-deps:10.0-noble-chiseled`	~12 MB

Chiseled images: Ubuntu-based, no shell, no package manager, non-root by default. Recommended for production.

Azure Linux distroless: Alternative to chiseled with Microsoft supply chain security. Similar benefits: no shell, non-root by default.

Standard Pattern

dockerfile

# syntax=docker/dockerfile:1

FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src

# Copy project files and restore (cache layer)
COPY *.csproj ./
RUN dotnet restore

# Copy source and publish
COPY . .
RUN dotnet publish -c Release -o /app/publish

# Runtime
FROM mcr.microsoft.com/dotnet/aspnet:10.0-noble-chiseled AS production
WORKDIR /app
COPY --from=build /app/publish .
USER app
EXPOSE 8080
ENTRYPOINT ["dotnet", "MyApp.dll"]

Multi-Project Solution Pattern

For solutions with multiple projects, copy all .csproj files first:

dockerfile

FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src

# Copy solution and project files (cache layer)
COPY *.sln ./
COPY src/MyApp/*.csproj ./src/MyApp/
COPY src/MyApp.Core/*.csproj ./src/MyApp.Core/
COPY tests/MyApp.Tests/*.csproj ./tests/MyApp.Tests/
RUN dotnet restore

# Copy everything and publish
COPY . .
RUN dotnet publish src/MyApp -c Release -o /app/publish

FROM mcr.microsoft.com/dotnet/aspnet:10.0-noble-chiseled AS production
WORKDIR /app
COPY --from=build /app/publish .
USER app
EXPOSE 8080
ENTRYPOINT ["dotnet", "MyApp.dll"]

Self-Contained Deployment

Bundles .NET runtime with app, enables smallest runtime-deps images:

dockerfile

FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src
COPY *.csproj ./
RUN dotnet restore
COPY . .
RUN dotnet publish -c Release -o /app/publish \
    --self-contained true \
    -r linux-x64

FROM mcr.microsoft.com/dotnet/runtime-deps:10.0-noble-chiseled AS production
WORKDIR /app
COPY --from=build /app/publish .
USER app
EXPOSE 8080
ENTRYPOINT ["./MyApp"]

Native AOT (Fastest Startup)

Compiles to native code. Smallest image (~12 MB), fastest startup:

dockerfile

FROM mcr.microsoft.com/dotnet/sdk:10.0-aot AS build
WORKDIR /src
COPY *.csproj ./
RUN dotnet restore
COPY . .
RUN dotnet publish -c Release -o /app/publish

FROM mcr.microsoft.com/dotnet/runtime-deps:10.0-noble-chiseled AS production
WORKDIR /app
COPY --from=build /app/publish .
USER app
EXPOSE 8080
ENTRYPOINT ["./MyApp"]

Dedicated AOT SDK images include native compilation prerequisites:

mcr.microsoft.com/dotnet/sdk:10.0-aot

(Ubuntu, also tagged

10.0-noble-aot

)

mcr.microsoft.com/dotnet/sdk:10.0-alpine-aot

mcr.microsoft.com/dotnet/sdk:10.0-azurelinux3.0-aot

Requires in .csproj:

xml

<PropertyGroup>
  <PublishAot>true</PublishAot>
</PropertyGroup>

Limitations: No runtime reflection, not all libraries compatible.

Dockerfile-less Container Publishing

.NET 10 supports publishing containers directly from the SDK—no Dockerfile required:

bash

# Publish to local container runtime
dotnet publish --os linux --arch x64 /t:PublishContainer

# Publish directly to a registry (no Docker needed)
dotnet publish --os linux --arch x64 /t:PublishContainer \
    -p ContainerRegistry=ghcr.io \
    -p ContainerRepository=myorg/myapp

# Multi-architecture publishing
dotnet publish /t:PublishContainer \
    -p ContainerRuntimeIdentifiers="linux-x64;linux-arm64"

Project file configuration:

xml

<PropertyGroup>
  <!-- Control image format: Docker or OCI -->
  <ContainerImageFormat>OCI</ContainerImageFormat>
  <!-- Customize base image -->
  <ContainerBaseImage>mcr.microsoft.com/dotnet/aspnet:10.0-noble-chiseled</ContainerBaseImage>
  <!-- Set image name and tag -->
  <ContainerRepository>myapp</ContainerRepository>
  <ContainerImageTag>1.0.0</ContainerImageTag>
</PropertyGroup>

Development Stage

Add a development stage for local dev with hot reload:

dockerfile

FROM mcr.microsoft.com/dotnet/sdk:10.0 AS base
WORKDIR /src
COPY *.csproj ./
RUN dotnet restore

FROM base AS development
COPY . .
ENTRYPOINT ["dotnet", "watch", "run"]

FROM base AS build
COPY . .
RUN dotnet publish -c Release -o /app/publish

FROM mcr.microsoft.com/dotnet/aspnet:10.0-noble-chiseled AS production
WORKDIR /app
COPY --from=build /app/publish .
USER app
EXPOSE 8080
ENTRYPOINT ["dotnet", "MyApp.dll"]

Build development:

docker build --target development -t myapp:dev .

Cache Optimization

Use BuildKit cache mount for NuGet packages:

dockerfile

RUN --mount=type=cache,target=/root/.nuget/packages \
    dotnet restore

SHA Pinning for Production

Pin exact image digests for reproducibility and security:

dockerfile

FROM mcr.microsoft.com/dotnet/sdk:10.0@sha256:abc123... AS build

To find the current digest, run:

bash

docker pull mcr.microsoft.com/dotnet/sdk:10.0
docker inspect --format='{{index .RepoDigests 0}}' mcr.microsoft.com/dotnet/sdk:10.0

Required .dockerignore

Always create

.dockerignore

dockerignore

**/bin/
**/obj/
**/.vs/
**/.vscode/
**/node_modules/
**/*.user
**/*.userosscache
**/*.suo
*.md
.git
.gitignore
Dockerfile*
docker-compose*

Verification Checklist

SDK image for build stage, runtime/aspnet for production
.NET 8+ uses port 8080 (not 80)
Copy .csproj files before source for cache efficiency
Use
```
USER app
```
for non-root execution (chiseled images have this user)
Chiseled images have no shell—use exec form only, no
```
&&
```
chains in final stage
Include .dockerignore to exclude build artifacts
Match runtime identifier (
```
-r linux-x64
```
) for self-contained builds
Consider SHA pinning for production reproducibility

dotnet-dockerfile

NPX Install

Tags

SKILL.md Content

.NET Dockerfile Generator

Workflow

Image Selection Guide

Standard Pattern

Multi-Project Solution Pattern

Self-Contained Deployment

Native AOT (Fastest Startup)

Dockerfile-less Container Publishing

Development Stage

Cache Optimization

SHA Pinning for Production

Required .dockerignore

Verification Checklist