🐳 Docker Basics

🎓 Final Project

11 🏗️ Build a Real Docker Project (End-to-End)

Build, containerize, run, and share a real ASP.NET Core app. Follow this exactly and you will have a working Docker project.

🎯 What You Will Build

A simple "Hello World" ASP.NET Core web app, packaged in a Docker container, running on your computer.

📁 Project Folder

Create a folder called HelloDocker anywhere on your PC.

🛠️ Step 1: Create the App

Open a terminal in that folder and run:

dotnet new web -n HelloDocker
cd HelloDocker

🛠️ Step 2: Change the Program.cs

Open Program.cs. Replace everything with:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello from Docker! 🐳 My first container is alive!");

app.Run();

🛠️ Step 3: Add a Dockerfile

In the HelloDocker folder, create a new file called Dockerfile (no extension). Paste:

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
WORKDIR /app
COPY *.csproj ./
RUN dotnet restore
COPY . ./
RUN dotnet publish -c Release -o out

FROM mcr.microsoft.com/dotnet/aspnet:8.0
WORKDIR /app
COPY --from=build /app/out .
ENTRYPOINT ["dotnet", "HelloDocker.dll"]

🛠️ Step 4: Add .dockerignore

Create a file called .dockerignore with:

bin/
obj/
*.user
*.suo

This keeps the image small and build fast.

🛠️ Step 5: Build the Image

In the same folder, run:

docker build -t hello-docker .

Wait for it to finish. The first time may take 1–2 minutes.

🛠️ Step 6: Run the Container

docker run -d -p 8080:80 --name my-hello-app hello-docker

This runs the container in the background.

🛠️ Step 7: Test It

Open your browser and go to:

http://localhost:8080

You should see: "Hello from Docker! 🐳 My first container is alive!"

🛠️ Step 8: Manage the Container

docker ps                # see it running
docker logs my-hello-app # see logs
docker stop my-hello-app # stop it
docker rm my-hello-app   # delete it

🛠️ Step 9: Share It (Bonus)

To share your image with others, push it to Docker Hub:

docker login
docker tag hello-docker YOUR_DOCKERHUB_USERNAME/hello-docker
docker push YOUR_DOCKERHUB_USERNAME/hello-docker

Anyone in the world can now run:

docker run -p 8080:80 YOUR_DOCKERHUB_USERNAME/hello-docker