Windows 10 (20H1 / 2004 / Mai 2020 Update) with WSL2 is out, this guide should be obsolete now.
Upgrading an existing WSL1 setup to WSL2
Note, this is only needed on Windows 10 Home and WSL1. If you have Windows 10 Pro, you can run Docker for Windows (https://docs.docker.com/docker-for-windows).
After completing this guide, you will have a Windows 10 Home running the docker deamon via Docker Toolbox / VirtualBox. The WSL guest OS will connect to this docker deamon, and will have the Windows OS filesystem mapped as C:\
-> /c/
instead of C:\
-> /mnt/c/
, which will fix path translation between docker deamon on Windows and docker client in WSL guest OS.