It will arrive first with Insider preview builds by the end of June, underpinning the new Windows Subsystem for Linux 2.
This is the first time that the Linux kernel will be included as part of Windows. The first release will be based on version 4.19, the latest stable Linux release.
“Beginning with Windows Insiders builds this summer, we will include an in-house custom-built Linux kernel to underpin the newest version of the Windows Subsystem for Linux (WSL). This marks the first time that the Linux kernel will be included as a component in Windows,” Jack Hammons, Program Manager, Linux Systems Group, Microsoft, writes in a blog post.
He explains that like WSL1, WSL2 will not provide any userspace binaries. Instead, the Microsoft kernel will interface with a userspace installed via the Windows Store. But it can also be “sideloaded” through the creation of a custom distribution package.
“The kernel itself will initially be based on version 4.19, the latest long-term stable release of Linux. The kernel will be rebased at the designation of new long-term stable releases to ensure that the WSL kernel always has the latest Linux goodness,” he says.
The WSL kernel will be fully open source
The WSL kernel will be built using Microsoft’s world-class CI/CD systems and serviced through Windows Update. The company promises to update the kernel with the newest features and fixes.
Jack continues –
“One of the great things about Linux is its stable and backwards compatible system call interface. This will enable us to ship the latest stable branch of the Linux kernel to all versions of WSL2. We will rebase the kernel when a new LTS is established and when we have sufficiently validated it.”
The kernel provided for WSL2 will be fully open source, meaning developers can create their own WSL kernel and contribute changes.
When WSL2 is released in Windows Insider builds, instructions for creating your own WSL kernel will be made available on Github, says Microsoft.