Docker containerization for .NET 10 applications. Covers multi-stage builds, .NET container images, non-root user configuration, health checks, and .dockerignore. Load this skill when containerizing an application with a Dockerfile, optimizing image size, setting up Docker Compose for local development, or when the user mentions "Docker", "Dockerfile", "container", "docker-compose", "image", "multi-stage", "non-root", ".dockerignore", or "container health check". For Dockerfile-less SDK publishing (`dotnet publish /t:PublishContainer`), load the container-publish skill instead.
Multi-stage builds always — Separate build and runtime stages. Build in the SDK image, run in the ASP.NET runtime image.
Non-root by default — .NET container images support USER app by default since .NET 8. Never run as root in production.
Layer caching matters — Copy .csproj files and restore before copying source code. This caches NuGet dependencies across builds.
Health probes at the orchestrator level — Expose a /health/live endpoint and let Kubernetes/Compose probe it. Chiseled and default aspnet images have no shell or curl, so in-image HEALTHCHECK commands have nothing to run with.
Patterns
Multi-Stage Dockerfile for Web API
# Stage 1: Build
FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
WORKDIR /src
