CODEWITHSUNDEEP
c#dockerasp.net-core.net-core
Will Custode
Will Custode

Reputation: 4594

It was not possible to find any installed .NET Core SDKs

I am trying to build a Docker image and run a container for my sample ASP.NET Core 3.1 app and am seeing

It was not possible to find any installed .NET Core SDKs

when I run the command

docker run --rm -it -p 8000:80 ppi

My Dockerfile is simple:

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
COPY publish/ ./
ENTRYPOINT ["dotnet", "sampleapp.dll"]

and I am pre-building my app into the publish folder. My folder structure looks as follows:

root/
  source/
    SampleApp.csproj
    appsettings.json
    Startup.cs
    Program.cs
  publish/
    SampleApp.dll
    SampleApp.exe
    appsettings.json
    SampleApp.deps.json
    SampleApp.runtimeconfig.json
    web.config
  Dockerfile
  SampleApp.sln

I created the image using the following command

docker build -t ppi

There are no issues with my sample app, as I'm able to launch it locally with the following command

dotnet publish/sampleapp.dll

What am I missing here? I've been working off of the following tutorials:

  1. Building .NET Docker Images
  2. dotnet-docket/samples/aspnetapp

Upvotes: 1

Views: 13818

Answers (3)

user1329695
user1329695

Reputation:

I had the same issue but did not want to build the app using the mcr.microsoft.com/dotnet/core/sdk:3.1-buster image. I discovered the shell running in the Linux container (bash) is case sensitive.

In your Dockerfile, change ENTRYPOINT ["dotnet", "sampleapp.dll"] to ENTRYPOINT ["dotnet", "SampleApp.dll"].

On Windows 10 either command will work since the shell there is case insensitive.

"Works on my machine..." anyone?

Upvotes: 2

mcmillab
mcmillab

Reputation: 2804

I get this error on Windows, when trying to run the Published version, ie just trying to use the runtime, not the sdk.

The solution for me was to change this:

dotnet sample

to this:

dotnet sample.dll

Upvotes: 0

Ziaullah Khan
Ziaullah Khan

Reputation: 2246

summary answer:

This image mcr.microsoft.com/dotnet/core/aspnet:3.1 is a .NET Runtime.

The recommended way of creating a docker image is to copy the code inside a dotnet sdk image. And fire all the build commands inside the docker image.

Once done. You copy only the publish folder to a dotnet runtime image (the one you are using).

If you are using visual studio; use the Add Docker Support option to generate a Dockerfile. And everything should work like a charm.

The error message is a little cryptic in saying that not all the files are present for running the application.

Your Dockerfile should look like below:

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim AS base
WORKDIR /app
EXPOSE 80

FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS build
WORKDIR /src
COPY ["myaspnetapp.csproj", ""]
RUN dotnet restore "./myaspnetapp.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "myaspnetapp.csproj" -c Release -o /app/build

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

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

Upvotes: 7

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