Microsoft is Adding a Linux kernel to Windows 10 to feed the Windows Subsystem for Linux. But guess what: you do not have to use the Linux kernel of Microsoft. You can create your own custom Linux kernel for Windows.
This feature is part of the new version of WSL in Insider Preview build 18945. This is a 20H1 version, which means it will probably be released in April 2020. It is unclear if this feature will reach 19H2, due out in October 2019.
Microsoft had already added the Linux kernel, but now, WSL 2 seems even more powerful than we thought. Now you can do anything with the Linux kernel, including adding modules to the kernel. You then specify the path to your kernel file in a .wslconfig file on your system and Windows will automatically load it each time you launch a Linux system. You do not need to load a custom kernel. If you do not, Windows will only use the built-in kernel.
Craig Loewen of Microsoft, Program Manager for the Windows Development Platform, explains:
we provides a Linux kernel with WSL 2, and it comes with Windows. However, you may want a specific kernel to feed your WSL 2 distributions, such as using a given kernel module, and so on. You can now use the kernel option of the .wslconfig file to specify the kernel path. machine, and this kernel will be loaded into the WSL virtual machine 2 when it starts. If no options are specified, you will use the Linux kernel supplied with Windows again as part of WSL 2.
There are also other improvements to WSL. The entire .wslconfig global configuration file is new and WSL 2 users can now connect to Linux servers running on their system using localhost.
This latest version of the insider preview also offers a redesigned Cortana experience, a streamlined file search in the file explorer and a customizable text cursor indicator.