Lesson 10 of 40 DevOps Intermediate 50 min

Docker & Container Development

In this lesson, you will learn how Visual Studio 2026 helps you containerize applications with Docker, manage multi-container setups, and debug applications running inside containers.

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What you will learn

How Docker support is added to a project
How multi-stage Dockerfiles work
How Docker Compose helps manage multiple services
How .NET Aspire fits into modern container workflows
How to debug code running in a container

Why this matters: Containers make applications easier to package, test, move, and deploy consistently across different environments.

Part 1: Adding Docker support

Visual Studio can generate Docker support directly from your project. This gives you a Dockerfile and related configuration so your application can be built and run inside a container.

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

FROM mcr.microsoft.com/dotnet/aspnet:10.0
COPY --from=build /app .
ENTRYPOINT ["dotnet", "MyApp.dll"]
    

A multi-stage Dockerfile helps keep the final image smaller by separating the build environment from the runtime environment.

Part 2: Docker Compose orchestration

Real applications often include more than one service, such as a web app, database, cache, or message broker. Docker Compose helps define and run those services together.

In Visual Studio, adding container orchestration support can generate a docker-compose.yml file and help launch the full environment more easily.

Example: A web API plus a SQL database is a common multi-container setup for local development.

Part 3: .NET Aspire integration

.NET Aspire focuses on cloud-native application development in .NET. Visual Studio 2026 makes it easier to start Aspire-based projects and inspect service interactions during development.

Create starter solutions for cloud-native development
Use built-in diagnostics and service visibility
Configure resilience and telemetry more easily

Aspire is especially useful when working with distributed applications and service-based architectures.

Part 4: Debugging in containers

One of the strengths of Visual Studio is that it can attach the debugger to a running container so the debugging experience stays familiar.

Set breakpoints as usual
Inspect variables and call stacks
Use watch windows and stepping tools
Debug the app while it runs inside its containerized environment

Benefit: This helps you test behavior closer to a real deployment setup instead of only on your local machine outside containers.

When to use each container tool

Tool	Best used for
Dockerfile	Defining how one application image is built
Docker Compose	Running multiple related services together
Container debugging	Investigating issues in containerized apps
.NET Aspire	Modern cloud-native and distributed .NET solutions

A practical container workflow

Step 1: Add Docker support to the project

Step 2: Review and understand the generated Dockerfile

Step 3: Add Docker Compose if your app needs supporting services

Step 4: Build and run the containerized app locally

Step 5: Debug inside the container when needed

Step 6: Refine images and settings before deployment

Best practices

Keep images as small as practical
Use multi-stage builds where appropriate
Separate configuration from application code
Test containers locally before deployment
Use orchestration only when it adds real value
Understand your runtime environment, not just your local editor setup

Summary

In this lesson, you learned how Visual Studio 2026 supports Docker, multi-container development, Aspire-based workflows, and container debugging.

In the next lesson, you will explore .NET MAUI cross-platform application development.