Application on Ubuntu Looking for .net Runtimes in Different Places

I am on Ubuntu using VS Code to write an AWS lambda function and debugging it with the AWS Mock Lambda tool.

When I run 'dotnet --info' I see this:

.NET Core runtimes installed:
  Microsoft.AspNetCore.App 3.1.32 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.32 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.14 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

I'm not sure why there are 2 folders, but it's creating a problem.

When I run VS Code, the project is dotnet 6.0, and it correctly finds that runtime in /usr/share/dotnet/shared/Microsoft.NETCore.App. I have reinstalled dotenet 6 several times using ./dotnet-install.sh and that is always where it is intstalled.

When I run it using the mock lambda tool, the code builds fine using the dotnet 6 runtime, but when the mock lambda tool tries to load, it throws this error:

The framework 'Microsoft.AspNetCore.App', version '6.0.0' was not found.
  - The following frameworks were found:
      3.1.32 at [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]

So VS Code it getting the runtime from: /usr/share/dotnet/shared/Microsoft.NETCore.App (correct)

But AWS Mock Lambda is looking in: /usr/share/dotnet/shared/Microsoft.AspNetCore.App

If I remove the runtime from /usr/share/dotnet/shared/Microsoft.AspNetCore.App, it says it cannot find any runtimes.

Is there a way I can tell the lambda tool to look in the correct folder? Or install dotnet 6 in the folder the lambda tool is look for it in?

This is my launch.json in VS Code:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Job Worker",
            "type": "coreclr",
            "request": "launch",
            "preLaunchTask": "build",
            "program": "dotnet-lambda-test-tool-6.0",
            "args": [],
            "cwd": "${workspaceFolder}/JobWorker",
            "console": "internalConsole",
            "stopAtEntry": false
        },
    ]
}

The description shows a common misconception about the runtimes.

There are indeed the .NET Core runtime Microsoft.NETCore.App and the ASP.NET Core runtime Microsoft.AspNetCore.App, so you should install ASP.NET Core 6 runtime to meet the requirement,

sudo apt-get install -y aspnetcore-runtime-6.0

https://learn.microsoft.com/en-us/dotnet/core/install/linux-ubuntu