Chapter 2. Using .NET Core 2.1 on Red Hat Enterprise Linux 7

Procedure

1. Enable the .NET Core software repositories:

   $ sudo subscription-manager repos --enable=rhel-7-variant-dotnet-rpms

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   Replace variant with server, workstation or hpc-node depending on what RHEL system you are running (RHEL 7 Server, RHEL 7 Workstation, or HPC Compute Node, respectively).

2. Verify the list of subscriptions attached to your system:

   $ sudo subscription-manager list --consumed

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3. Install the scl tool:

   $ sudo yum install scl-utils -y

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4. Install .NET Core 2.1 and all of its dependencies:

   $ sudo yum install rh-dotnet21 -y

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5. Enable the rh-dotnet21 Software Collection environment:

   $ scl enable rh-dotnet21 bash

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   You can now run dotnet commands in this bash shell session.

   If you log out, use another shell, or open up a new terminal, the dotnet command is no longer enabled.

   Warning

   Red Hat does not recommend permanently enabling rh-dotnet21 because it may affect other programs. For example, rh-dotnet21 includes a version of libcurl that differs from the base RHEL version. This may lead to issues in programs that do not expect a different version of libcurl. If you want to enable rh-dotnet permanently, add source scl_source enable rh-dotnet21 to your ~/.bashrc file.

Procedure

1. Create a new Console application in a directory called my-app:

   $ dotnet new console --output my-app

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   The output returns:

     The template "Console Application" was created successfully.
   
     Processing post-creation actions...
     Running 'dotnet restore' on my-app/my-app.csproj...
     Restoring packages for /home/username/my-app/my-app.csproj...
     Generating MSBuild file /home/username/my-app/obj/my-app.csproj.nuget.g.props.
     Generating MSBuild file /home/username/my-app/obj/my-app.csproj.nuget.g.targets.
     Restore completed in 224.85 ms for /home/username/my-app/my-app.csproj.
   
     Restore succeeded.

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   A simple Hello World console application is created from a template. The application is stored in the specified my-app directory.

   The directory includes the following files:

   $ tree my-app
   my-app
   ├── my-app.csproj
   ├── obj
   │   ├── my-app.csproj.nuget.dgspec.json
   │   ├── my-app.csproj.nuget.g.props
   │   ├── my-app.csproj.nuget.g.targets
   │   ├── project.assets.json
   │   └── project.nuget.cache
   └── Program.cs
   
   1 directory, 7 files

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Procedure

1. Create a new MVC project in a directory called mvc_runtime_example:

   $ dotnet new mvc --output mvc_runtime_example --no-restore

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2. Restore and publish the project:

   $ dotnet restore mvc_runtime_example -r rhel.7-x64
   $ dotnet publish mvc_runtime_example -f netcoreapp2.1 -c Release -r rhel.7-x64 --self-contained false /p:MicrosoftNETPlatformLibrary=Microsoft.NETCore.App

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3. Create the Dockerfile:

   $ cat > Dockerfile <<EOF
   FROM registry.redhat.io/dotnet/dotnet-21-runtime-rhel7
   
   ADD bin/Release/netcoreapp2.1/publish/ .
   
   CMD ["dotnet", "mvc_runtime_example.dll"]
   EOF

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4. Build your image:

   $ podman build -t dotnet-21-runtime-example .

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   Note

   If you get an error containing the message unable to retrieve auth token: invalid username/password, you need to provide credentials for the registry.redhat.io server. Use the command podman login registry.redhat.io to log in. Your credentials are typically the same as those used for the Red Hat Customer Portal.

5. Run your image:

   $ podman run -d -p8080:8080 dotnet-21-runtime-example

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