无法在dockerfile中使用dotnet命令？

Question

我一直在尝试为我的asp.net网络api创建一个dockerfile。互联网上的许多指南都使用此RUN dotnet restore RUN dotnet publish命令，但是我在这里遇到错误。

我的dockerfile：

FROM microsoft/dotnet:sdk AS build-env
WORKDIR /app

EXPOSE 5000

# Copy csproj and restore as distinct layers
COPY *.csproj ./
RUN dotnet restore

# Copy everything else and build
COPY . ./
RUN dotnet publish -c Release -o out

# Build runtime image
FROM microsoft/dotnet:aspnetcore-runtime
WORKDIR /app
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "myTest.dll"]

然后我遇到这个错误：

Step 5/11 : RUN dotnet restore ---> Running in 592b7df3e0f6 Restoring packages for C:\app\myTest.csproj... C:\Program Files\dotnet\sdk\2.1.402\NuGet.targets(114,5): error : Unable to load the service index for source https://api.nuget.org/v3/index.json. [C:\app\myTest.csproj] C:\Program Files\dotnet\sdk\2.1.402\NuGet.targets(114,5): error : No such host is known [C:\app\myTest.csproj] The command 'cmd /S /C dotnet restore' returned a non-zero code: 1

有人可以解释/帮助我吗？