--- title: Docker images for ASP.NET Core author: tdykstra description: Learn how to use the published .NET Core Docker images from the Docker Registry. Pull images and build your own images. ms.author: tdykstra ms.custom: mvc ms.date: 04/09/2019 uid: host-and-deploy/docker/building-net-docker-images --- # Docker images for ASP.NET Core This tutorial shows how to run an ASP.NET Core app in Docker containers. In this tutorial, you: > [!div class="checklist"] > * Learn about Microsoft .NET Core Docker images > * Download an ASP.NET Core sample app > * Run the sample app locally > * Run the sample app in Linux containers > * Run the sample app in Windows containers > * Build and deploy manually ## ASP.NET Core Docker images For this tutorial, you download an ASP.NET Core sample app and run it in Docker containers. The sample works with both Linux and Windows containers. The sample Dockerfile uses the [Docker multi-stage build feature](https://docs.docker.com/engine/userguide/eng-image/multistage-build/) to build and run in different containers. The build and run containers are created from images that are provided in Docker Hub by Microsoft: * `dotnet/core/sdk` The sample uses this image for building the app. The image contains the .NET Core SDK, which includes the Command Line Tools (CLI). The image is optimized for local development, debugging, and unit testing. The tools installed for development and compilation make this a relatively large image. * `dotnet/core/aspnet` The sample uses this image for running the app. The image contains the ASP.NET Core runtime and libraries and is optimized for running apps in production. Designed for speed of deployment and app startup, the image is relatively small, so network performance from Docker Registry to Docker host is optimized. Only the binaries and content needed to run an app are copied to the container. The contents are ready to run, enabling the fastest time from `Docker run` to app startup. Dynamic code compilation isn't needed in the Docker model. ## Prerequisites * [.NET Core 2.2 SDK](https://www.microsoft.com/net/core) * Docker client 18.03 or later * Linux distributions * [CentOS](https://docs.docker.com/install/linux/docker-ce/centos/) * [Debian](https://docs.docker.com/install/linux/docker-ce/debian/) * [Fedora](https://docs.docker.com/install/linux/docker-ce/fedora/) * [Ubuntu](https://docs.docker.com/install/linux/docker-ce/ubuntu/) * [macOS](https://docs.docker.com/docker-for-mac/install/) * [Windows](https://docs.docker.com/docker-for-windows/install/) * [Git](https://git-scm.com/download) ## Download the sample app * Download the sample by cloning the [.NET Core Docker repository](https://github.com/dotnet/dotnet-docker): ```console git clone https://github.com/dotnet/dotnet-docker ``` ## Run the app locally * Navigate to the project folder at *dotnet-docker/samples/aspnetapp/aspnetapp*. * Run the following command to build and run the app locally: ```console dotnet run ``` * Go to `http://localhost:5000` in a browser to test the app. * Press Ctrl+C at the command prompt to stop the app. ## Run in a Linux container * In the Docker client, switch to Linux containers. * Navigate to the Dockerfile folder at *dotnet-docker/samples/aspnetapp*. * Run the following commands to build and run the sample in Docker: ```console docker build -t aspnetapp . docker run -it --rm -p 5000:80 --name aspnetcore_sample aspnetapp ``` The `build` command arguments: * Name the image aspnetapp. * Look for the Dockerfile in the current folder (the period at the end). The run command arguments: * Allocate a pseudo-TTY and keep it open even if not attached. (Same effect as `--interactive --tty`.) * Automatically remove the container when it exits. * Map port 5000 on the local machine to port 80 in the container. * Name the container aspnetcore_sample. * Specify the aspnetapp image. * Go to `http://localhost:5000` in a browser to test the app. ## Run in a Windows container * In the Docker client, switch to Windows containers. Navigate to the docker file folder at `dotnet-docker/samples/aspnetapp`. * Run the following commands to build and run the sample in Docker: ```console docker build -t aspnetapp . docker run -it --rm --name aspnetcore_sample aspnetapp ``` * For Windows containers, you need the IP address of the container (browsing to `http://localhost:5000` won't work): * Open up another command prompt. * Run `docker ps` to see the running containers. Verify that the "aspnetcore_sample" container is there. * Run `docker exec aspnetcore_sample ipconfig` to display the IP address of the container. The output from the command looks like this example: ```console Ethernet adapter Ethernet: Connection-specific DNS Suffix . : contoso.com Link-local IPv6 Address . . . . . : fe80::1967:6598:124:cfa3%4 IPv4 Address. . . . . . . . . . . : 172.29.245.43 Subnet Mask . . . . . . . . . . . : 255.255.240.0 Default Gateway . . . . . . . . . : 172.29.240.1 ``` * Copy the container IPv4 address (for example, 172.29.245.43) and paste into the browser address bar to test the app. ## Build and deploy manually In some scenarios, you might want to deploy an app to a container by copying to it the application files that are needed at run time. This section shows how to deploy manually. * Navigate to the project folder at *dotnet-docker/samples/aspnetapp/aspnetapp*. * Run the [dotnet publish](https://docs.microsoft.com/dotnet/core/tools/dotnet-publish.md) command: ```console dotnet publish -c Release -o published ``` The command arguments: * Build the application in release mode (the default is debug mode). * Create the files in the *published* folder. * Run the application. * Windows: ```console dotnet published\aspnetapp.dll ``` * Linux: ```bash dotnet published/aspnetapp.dll ``` * Browse to `http://localhost:5000` to see the home page. ### The Dockerfile Here's the Dockerfile used by the `docker build` command you ran earlier. It uses `dotnet publish` the same way you did in this section to build and deploy. ```console FROM mcr.microsoft.com/dotnet/core/sdk:2.2 AS build WORKDIR /app # copy csproj and restore as distinct layers COPY *.sln . COPY aspnetapp/*.csproj ./aspnetapp/ RUN dotnet restore # copy everything else and build app COPY aspnetapp/. ./aspnetapp/ WORKDIR /app/aspnetapp RUN dotnet publish -c Release -o out FROM mcr.microsoft.com/dotnet/core/aspnet:2.2 AS runtime WORKDIR /app COPY --from=build /app/aspnetapp/out ./ ENTRYPOINT ["dotnet", "aspnetapp.dll"] ``` ## Additional resources * [Docker build command](https://docs.docker.com/engine/reference/commandline/build) * [Docker run command](https://docs.docker.com/engine/reference/commandline/run) * [ASP.NET Core Docker sample](https://github.com/dotnet/dotnet-docker) (The one used in this tutorial.) * [Configure ASP.NET Core to work with proxy servers and load balancers](/aspnet/core/host-and-deploy/proxy-load-balancer) * [Working with Visual Studio Docker Tools](https://docs.microsoft.com/aspnet/core/publishing/visual-studio-tools-for-docker) * [Debugging with Visual Studio Code](https://code.visualstudio.com/docs/nodejs/debugging-recipes#_debug-nodejs-in-docker-containers) ## Next steps In this tutorial, you: > [!div class="checklist"] > * Learned about Microsoft .NET Core Docker images > * Downloaded an ASP.NET Core sample app > * Run the sample app locally > * Run the sample app in Linux containers > * Run the sample with in Windows containers > * Built and deployed manually The Git repository that contains the sample app also includes documentation. For an overview of the resources available in the repository, see [the README file](https://github.com/dotnet/dotnet-docker/blob/master/samples/aspnetapp/README.md). In particular, learn how to implement HTTPS: > [!div class="nextstepaction"] > [Developing ASP.NET Core Applications with Docker over HTTPS](https://github.com/dotnet/dotnet-docker/blob/master/samples/aspnetapp/aspnetcore-docker-https-development.md)