Microsoft's CBL-Delridge is 404, long live CBL-Mariner

Microsoft is increasingly standardizing on its in-house CBL-Mariner Linux distribution. Is this Microsoft Linux?

Microsoft's CBL-Delridge is 404, long live CBL-Mariner

CBL-Delridge, Microsoft's Debian-based Linux distribution, is no more. As pointed out to me by Mary Jo Foley, the CBL-Delridge apt package repository, is now 404:

I had previously written a guide to building your own image of CBL-Delridge from that repository:

Building CBL-Delridge, Microsoft’s other Linux distro
Microsoft has another Linux distro you probably haven’t heard of. You can easily build it and even import it into WSL.

I am afraid that method will no longer work.

Mary Jo Foley also wrote about CBL-Delridge:

Surprise: There’s yet another Microsoft Linux distro, CBL-Delridge
Microsoft has been public about its CBL-Mariner Linux release, which just hit the 2.0 milestone. But did you know there’s also a Microsoft CBL-Delridge?

The only external use of CBL-Delridge by Microsoft, to my knowledge, was in Azure Cloud Shell, the shell built into Azure's web portal interface and Windows Terminal:

But you will notice if you login to Azure Cloud Shell now, another Linux distro is powering ACS, Microsoft's CBL-Mariner:

CBL is short for "Common Base Linux", which originally appeared to apply to a whole family of Linux distros within Microsoft, but Microsoft appears to be increasingly consolidating efforts about CBL-Mariner.

Microsoft describes CBL-Mariner as "an internal Linux distribution for Microsoft’s cloud infrastructure and edge products and services" but it now powers such diverse offerings as:

  • Azure Cloud Shell
  • Azure Kubernetes Service (AKS)
  • The lightweight layer that runs above your distro of choice on Windows Subsystem for Linux (WSL)

Unlike Debian and thus .deb-based CBL-Delridge, CBL-Mariner is .rpm-based, with .spec files borrowed from VMware's Photon OS, openmamba, and the Fedora Project. The project also acknowledges Linux from Scratch, so despite being .rpm-based, CBL-Mariner is not a derivative of Red Hat Enterprise Linux, Fedora, or SUSE Linux. It is something new.

Also unlike CBL-Delridge, Microsoft makes installable .ISO images available for CBL-Mariner.

The GUI installer on the ISO is quite fast. A full installation on a VM with just 4GB of RAM took 64 seconds.

And CBL-Mariner is proud of its install speed too:

You can browse the packages available in CBL-Mariner's default repository. While there is no official GUI desktop, there are some interesting GNOME packages landing in the repository:

Development on CBL-Mariner is quite active, with 223 releases to date on both the 1.0 and 2.0 release branches:

CBL-Mariner even provides detailed instructions on how it is built:

And how to build it yourself:

You can learn more from CBL-Mariner's GitHub page:

GitHub - microsoft/CBL-Mariner: Linux OS for Azure 1P services and edge appliances
Linux OS for Azure 1P services and edge appliances - GitHub - microsoft/CBL-Mariner: Linux OS for Azure 1P services and edge appliances

Or Microsoft's official documentation for CBL-Mariner:

CBL-Mariner Documentation
CBL-Mariner is an internal Linux distribution built by Microsoft for use in Azure

So, the question is, is CBL-Mariner going to be Microsoft Linux?