We worked around the issue by copying the files from a developer machine with VS 2017 Community installed. This works with MSBuild 32bit, it might not work with the 64bit version.

Copy the Sdks folder from a computer with VS2017 from C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild to the build server in C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\MSBuild

This one has already been fixed as of 15.3 which introduced SDK Resolvers. Just install a .NET Core SDK (manual or through the Build Tools installer) and viola.

This has been addressed in the Preview release for Visual Studio 15.7. If you'd like to try out the fix, you can access the preview build here: https://www.visualstudio.com/vs/preview.

This issue has been fixed and is now available in our latest update. You can download the update via the in-product notification or from here: https://www.visualstudio.com/vs/ Thanks to everyone who provided feedback, votes and solutions for this problem.

You can look for the files somewhere else, we had the same files in a SDK folder on our build machine and I took these. But they will also be on DEV machines and you can copy these.