Fixing The specified framework 'Microsoft.AspNetCore.App', version '2.1.1'

Question

• Visual Studio 2017 15.8.1
• New Empty .NET Core MVC Application with Docker support generated via new project wizard

As soon as I run the application I get the errors:

The specified framework 'Microsoft.AspNetCore.App', version '2.1.1' was not found.
  - Check application dependencies and target a framework version installed at:
      /usr/share/dotnet/
  - Installing .NET Core prerequisites might help resolve this problem:
      http://go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409
  - The .NET Core framework and SDK can be installed from:
      https://aka.ms/dotnet-download
  - The following versions are installed:
      2.1.0 at [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
The target process exited without raising a CoreCLR started event. Ensure that the target process is configured to use .NET Core. This may be expected if the target process did not run on .NET Core.

However I have checked and I have the following installed:

C:\Users\homer>dotnet --list-sdks
1.0.0-preview2-003121 [C:\Program Files\dotnet\sdk]
1.0.0-preview2-003131 [C:\Program Files\dotnet\sdk]
1.0.3 [C:\Program Files\dotnet\sdk]
1.0.4 [C:\Program Files\dotnet\sdk]
1.1.0 [C:\Program Files\dotnet\sdk]
2.0.2 [C:\Program Files\dotnet\sdk]
2.0.3 [C:\Program Files\dotnet\sdk]
2.1.2 [C:\Program Files\dotnet\sdk]
2.1.4 [C:\Program Files\dotnet\sdk]
2.1.100 [C:\Program Files\dotnet\sdk]
2.1.101 [C:\Program Files\dotnet\sdk]
2.1.103 [C:\Program Files\dotnet\sdk]
2.1.104 [C:\Program Files\dotnet\sdk]
2.1.201 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.300 [C:\Program Files\dotnet\sdk]
2.1.301 [C:\Program Files\dotnet\sdk]
2.1.400 [C:\Program Files\dotnet\sdk]

C:\Users\homer>dotnet --list-runtimes
Microsoft.AspNetCore.All 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 1.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

So as far as I can tell it is installed. Clearly I have something wrong in my unchanged project files somewhere.

Dockerfile

FROM microsoft/dotnet:2.1-aspnetcore-runtime AS base
WORKDIR /app
EXPOSE 19354
EXPOSE 44350

FROM microsoft/dotnet:2.1-sdk AS build
WORKDIR /src
COPY ["WebApplication4/WebApplication4.csproj", "WebApplication4/"]
RUN dotnet restore "WebApplication4/WebApplication4.csproj"
COPY . .
WORKDIR "/src/WebApplication4"
RUN dotnet build "WebApplication4.csproj" -c Release -o /app

FROM build AS publish
RUN dotnet publish "WebApplication4.csproj" -c Release -o /app

FROM base AS final
WORKDIR /app
COPY --from=publish /app .
ENTRYPOINT ["dotnet", "WebApplication4.dll"]

cproj

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <DockerTargetOS>Linux</DockerTargetOS>
    <UserSecretsId>9476cca2-b6a8-4c0e-a766-a2e480ded46a</UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.0.1916590" />
    <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
  </ItemGroup>

</Project>

So what have I missed here to make this work?

Answer 1

Amending the Dockerfile to (Note the 2.1.1 instead for 2.1) fixed the issue:

FROM microsoft/dotnet:2.1.1-aspnetcore-runtime AS base
WORKDIR /app
EXPOSE 19354
EXPOSE 44350

FROM microsoft/dotnet:2.1.1-sdk AS build
WORKDIR /src
COPY ["WebApplication4/WebApplication4.csproj", "WebApplication4/"]
RUN dotnet restore "WebApplication4/WebApplication4.csproj"
COPY . .
WORKDIR "/src/WebApplication4"
RUN dotnet build "WebApplication4.csproj" -c Release -o /app

FROM build AS publish
RUN dotnet publish "WebApplication4.csproj" -c Release -o /app

FROM base AS final
WORKDIR /app
COPY --from=publish /app .
ENTRYPOINT ["dotnet", "WebApplication4.dll"]

Wouldn't it be great if M$ actually looked at what is installed on your machine and generate the correct file. :-)

Answer 2

I had the same issue and simply changed the version to 2.0. Not exactly a fix for your problem but will probably let you run the project.

To do this, unload your project, then edit the project file and change the netcoreapp2.1 to netcoreapp2.0