Do you need License for OS (Windows) inside Docker
The container images will use the underlying OS license. Microsoft calls it supplmental license.
You are licensed to use this Supplement in conjunction with the underlying host operating system software (“Host Software”) solely to assist running the containers feature in the Host Software. The Host Software license terms apply to your use of the Supplement. You may not use it if you do not have a license for the Host Software. You may use this Supplement with each validly licensed copy of the Host Software.