Docker - .Net Core

Sukhpinder Singh - Jun 10 '21 - - Dev Community

Docker container renders a lightweight way to separate your application from the rest of the host system, utilizing the resources enabled.

Prerequisites

  • More Info on Docker: Link

  • Install Docker Desktop (Community Edition): Link

  • Install .Net Core: Link

Getting Started

This article covers
  • Create and publish a “Hello World” .Net Core App.

  • Create and configure Dockerfile for .Net Core.

  • Build a Docker Image.

  • Create and run a docker container.

Create and publish a “Hello World” .Net Core App.

Fire a new command prompt in “Administration Mode” and create a new .Net core application using the following command.

dotnet new console -o App -n NetCore.Docker
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The command will generate a new folder named “App” and create a Hello World .Net core application inside it.

To test the console application, run below command.

dotnet run
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The preceding command will output Hello World onto the console.

Before containerizing the app, first it must be published. Create a publish build of a .Net Core application run below command with the “Release” parameter.

dotnet publish -c Release
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The preceding command will generate a published version of Hello World application into the following path.

.\bin\Release\netcoreapp3.1\publish\
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Create and configure Dockerfile for .Net Core

After necessary .Net Core application setup is ready and published, let’s move on to create a docker file.

Create a file named “Dockerfile” in the App folder directory. Open the created file and place the below fragment into it & Save.

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
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The above line instructs Docker to use .Net Core Runtime environment, which is relevant for .Net Core application created above.

Build a docker image

Docker will process all lines inside the Dockerfile. The “.” character in the build command tells Docker to use the existing folder to find the Dockerfile.

docker build -t counter-image -f Dockerfile.txt .
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To verify images list, run below command

docker images
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Output

Create and run a docker container

Create Container

After a container is running, you can establish a connection to see the output. However, to create a container applying below command.

docker create --name core-counter counter-image
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Run a docker container

Below command perform two things, first, automatically use the command prompt to connect to the container, and then when the container completes the task, remove it.

docker run -it --rm counter-image
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