Create a ASP.NET Core Docker Image

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Create a ASP.NET Core Docker Image

This is a simple demo for creating a Docker image for an ASP.NET Core application.

Before starting, ensure you have the following requirements:

  1. Install Docker.

  2. Install the .NET SDK.

  3. Prepare an ASP.NET Core application. You can create a new ASP.NET Core Web API project using the following command:

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    $ dotnet new web -n Demo

Create a Dockerfile

Create a Dockerfile in your project directory:

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# Use the official ASP.NET runtime image as a base
FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
WORKDIR /app

# Use the .NET SDK image to build the application
FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
WORKDIR /src
COPY ["Demo/Demo.csproj", "Demo/"]
RUN dotnet restore "Demo/Demo.csproj"
COPY . .
WORKDIR "/src/Demo"
RUN dotnet build "Demo.csproj" -c Release -o /app/build

# Publish the application
FROM build AS publish
RUN dotnet publish "Demo.csproj" -c Release -o /app/publish

# Final stage: use the runtime image to run the app
FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "Demo.dll"]

Build the Docker Image

Build the Docker image with the following command:

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$ docker build -t demo-docker -f Dockerfile .

The result will end like:

docker-build-image

List Docker Images

After building the Docker image, you can list all Docker images with:

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$ docker images

The result will like:

docker-list-images

Run the Container

Using Docker CLI

To run the container in detached mode, use:

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$ docker run -d -p 8080:80 --name demo-docker demo-docker

Using Docker Compose

  1. Create a docker-compose.yml file. Replace <service_name>, <image_name>, and <container_name> with your actual values.

    Note: Starting from .NET 8, the default port is 8080.

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    version: '3'
    services:
      <service_name>:
        image: <image_name>
        container_name: <container_name>
        ports:
          - 5000:8080
        volumes:
          - /home/user/files:/files

    This example mounts the /home/user/files directory on the host to the /files directory inside the container.

    The docker-compose.yml file can also include multiple services, for example:

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    version: '3'
    services:
      <service_name1>:
        image: <image_name1>
        container_name: <container_name1>
        ports:
          - 5000:8080
        volumes:
          - /home/user/files:/files

      <service_name2>:
        image: <image_name2>
        container_name: <container_name2>
        ports:
          - 6000:8080

  2. Start the container in detached mode with Docker Compose:

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    $ docker-compose up -d

  3. To check the status of your container:

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    $ docker ps

References