BenchMark Quizzes by MDFT Pro

Create Dockerfile for ASP.NET Core Application

You work as a Platform Engineer for MDFT Pro, a well-known training agency that delivers professional development courses globally. Mark, the lead DevOps specialist, has asked you to containerize the Learning Portal application, an ASP.NET Core web app that students use to access course materials and track their progress.

You have been provided with a setup script named setupScript.ps1 that configures the application environment and the compiled application files including LearningPortal.dll. The Dockerfile must be created in the same folder where LearningPortal.dll and setupScript.ps1 are stored. The setup script must run during the container build process, and the application must start automatically when the container launches.

Which five commands should you include in the Dockerfile to meet these requirements?

Choose all correct answers from the options below.

Explanations for each answer:

FROM mcr.microsoft.com/dotnet/aspnet:latest is correct. This command sets the base image to the ASP.NET Core runtime, which is appropriate for running compiled ASP.NET Core applications. The aspnet image is lighter than the SDK image and contains only what's needed to run the application.
FROM mcr.microsoft.com/dotnet/sdk:latest is incorrect. The SDK image is used for building applications, not running them. Since the requirement is to run a pre-built application (the DLL already exists), using the SDK image would unnecessarily increase the container size without providing additional benefits.
WORKDIR /apps/LearningPortal is correct. This command sets the working directory inside the container where subsequent commands will be executed. It creates a clean, organized structure for the application files within the container.
COPY /apps/LearningPortal/ . is incorrect. This command attempts to copy files from an absolute path outside the container, but this path doesn't exist. Instead, we should copy files from a relative path based on where the Dockerfile is located.
COPY ./ . is correct. This copies all files from the current build context (where the Dockerfile is located) into the working directory of the container. Since the Dockerfile must be in the same folder as the application files, this correctly copies all necessary files.
RUN powershell ./setupScript.ps1 is correct. The RUN command executes during the image build process, which is the correct time to run setup scripts. This ensures the container is properly configured before it's ready to run the application.
RUN dotnet ./LearningPortal.dll is incorrect. Using RUN to start the application would attempt to run it during the build process, which would cause the build to hang or fail. The application should only start when the container starts, not during the build.
CMD ["dotnet", "LearningPortal.dll"] is correct. The CMD instruction defines the command that runs when the container starts. This is the correct way to specify that the application should run when the container is launched, not during the build process.
CMD ["powershell", "./setupScript.ps1"] is incorrect. Setting the setup script as the CMD would run it every time the container starts, not during the build. Additionally, once the script completes, the container would exit, preventing the application from running.

Learn more about Containerizing .NET Applications:

Containerize .NET Apps

Practice Exam

Create Dockerfile for ASP.NET Core Application

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