The specified framework 'Microsoft.AspNetCore.App', version '2.1.8' was not found. with docker

Question

I have a project compiling with .net core 2.1

The project is very simple:

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

<PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
</PropertyGroup>

<ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" Version="2.1.1" />
</ItemGroup>

I have these two libraries reference:

It compiles and runs properly on the host.

I made a docker image:

FROM microsoft/dotnet:2.1-sdk AS build

COPY ./Test /src/Test
WORKDIR /src/Test
RUN dotnet build -c Release -o /app

FROM build AS publish
RUN dotnet publish -c Release -o /app --no-restore

FROM microsoft/dotnet:2.1-runtime AS final
WORKDIR /app
COPY --from=publish /app .

CMD ["dotnet", "Test.dll"]

It builds properly, no warnings.

But when I execute it:

# dotnet Test.dll
It was not possible to find any compatible framework version
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:
  https://go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409
  - The .NET Core framework and SDK can be installed from:
  https://aka.ms/dotnet-download

So, when I check the framework version (I build with dotnet:2.1-runtime):

# dotnet --info

Host (useful for support):
  Version: 2.1.8
  Commit:  209f8aa25c

.NET Core SDKs installed:
  No SDKs were found.

.NET Core runtimes installed:
  Microsoft.NETCore.App 2.1.8 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

So it looks like 2.1.8 is installed and somehow, it can't do the role of 2.1.1.

I tried two things:

update my libs to version 2.1.8... then it can't find version 2.1.8 of the asp lib
not put any version requirement in the csproj file and it can't find the asp lib either

How to get this working?

Your docker files look ok to me, as I'm using almost an identical set (using the dotnet:2.1-aspnetcore-runtime and sdk instead of the base dotnet one). — Marshall Tigerus

Thomas Thomas · Accepted Answer · 2019-03-01T18:32:06

I found that when using ASP, you can’t use the .net core image and add asp libraries.

You need to take the .net core asp docker image.

The specified framework 'Microsoft.AspNetCore.App', version '2.1.8' was not found. with docker

1 Answers