I've written before about .net core with docker and using it with .net core 2.1

But as .net core has moved forward through new versions the docker files change, this is a sample docker file for a .net core 2.2 web app.

FROM microsoft/dotnet:2.2-sdk-alpine3.8 AS build
WORKDIR /app

# copy csproj and restore as distinct layers
COPY *.sln .
COPY Serversncodenetcore2.2_docker/*.*.csproj ./Serversncodenetcore2.2_docker/
RUN dotnet restore

# copy everything else and build app
COPY Serversncodenetcore2.2_docker/. ./Serversncodenetcore2.2_docker/
WORKDIR /app/Serversncodenetcore2.2_docker
RUN dotnet publish -c Release -o out

FROM microsoft/dotnet:2.2.0-aspnetcore-runtime  AS runtime
WORKDIR /app
COPY --from=build /app/Serversncodenetcore2.2_docker/out ./
ENTRYPOINT ["dotnet", "Serversncodenetcore2.2_docker.dll"]

The big difference from 2.1 is the images we use. In this case I am using the 2.2-sdk-alpine3.8 as my build image.

microsoft/dotnet:2.2-sdk-alpine3.8

For the runtime I use the 2.2.0-aspnetcore-runtime

microsoft/dotnet:2.2.0-aspnetcore-runtime