An assembly specified in the application dependencies manifest (...) was not found

Try to use this image "2.0.0-preview1". Basically change the first line to FROM microsoft/aspnetcore:2.0.0-preview1, if your local has preview 1 dotnet core.

If it not works, check your local dotnet core version, it it points to 2.0.0-preview2-final, then change all your references pointing to 2.0.0-preview2-final in csproj file, then use the 2.0.0-preview2 image. It would help you I hope.

You need to specify -r linux-x64 parameter in dotnet publish command like that:

dotnet publish -o obj/Docker/publish -c Release -r linux-x64

This will make a standalone deployment.