Besides Azure Cloud Switch as a Linux platform created by Microsoft, the Windows company has also been developing CBL-Mariner (Common Base Linux) as their own internal albeit public and open-source Linux distribution.
CBL-Mariner is a product of Microsoft’s Linux engineers and is used as an internal distribution by their engineer teams for cloud, edge, and other needs within the company. The code to CBL-Mariner though is public under their GitHub organization although no official builds are provided besides some pre-compiled RPMs. CBL-Mariner is used by the likes of Windows Subsystem for Linux (WSL), Azure Sphere OS, SONiC, and other Linux-based efforts at the Redmond giant.
CBL-Mariner is security-focused, makes use of RPMs with DNF / Tiny DNF for package management, various installation types, and more. But again it’s not aiming to be a general purpose Linux distribution but one that various Microsoft engineering teams can use for their different varying use-cases.
The most recent CBL-Mariner 1.0 update came last week with a shift to the latest Linux 5.10 LTS kernel point release, various security fixes, demoting of Kubernetes to their Extras repository, and various other packages added. Details on that latest Microsoft Linux distribution update via the GitHub project.
More fundamental details on CBL-Mariner can be found via this blog post by Juan Manuel Rey of Microsoft’s Azure team.
