Azure Linux 4.0 is Microsoft's first general-purpose Linux

No it's not. It's for tuned for Azure. Nobody is running this outside of their compute environment.

call me old fashioned isn't a general purpose OS one that runs on any hardware and set up? and is certified with hardware vendors for full backing and support?

all this says is: "MS now provides a unified Linux from WSL to the MS cloud. just like what you got w/ SUSE RH canonical up to now. but without any support outside the MS stack.", right?

or am I missing something?

Surprised it doesn't have Copilot in the name somewhere

Previously (61 points, 17 days ago, 49 comments) https://news.ycombinator.com/item?id=48187736

Microsoft's Azure Linux (66 points, 4 months ago, 109 comments) https://news.ycombinator.com/item?id=46805841

Moving from tdnf to dnf5 is interesting. Most internal platforms get more bespoke over time, not less.

"Microsoft’s in-house Linux, the distribution that grew out of CBL-Mariner, just hit public preview as a general-purpose cloud OS you can run on any Azure VM. Here is why that is a real step in Microsoft’s Linux journey, not just a version bump."

Christ, they even lead with AI slop.

How desperate is Microsoft right now? Their model website was trying hard to be Anthropic, now they claim they have a linux distro? Which is just a tuned version?

What's next?

What advantages does Azure Linux have compared to Ubuntu?

Embrace, Extend, Extinguish anyone? Although, as a Fedora user I'm happy it's RPM based.

Microsoft are pieces of shit lads. Run by nonces. Also 4.0, first? Lord give me strength.

This is a nonevent, unless perhaps some genuine "general purpose" tools come out of this. MS will never contribute to things such as Wine and Proton and kill its golden goose.

Microsoft was a *nix supporter from the very beginning, with Microsoft Xenix.

[laughs in Torvalds.]

Tldr a MSFT maintained fedora fork tuned for Azure hardware.

Microsoft are pieces of shit lads. Run by nonces. Also 4.0, first? Lord give me strength.

Read the article. MS have shipped 1.0-3.0 earlier...

"Azure Linux 4.0 is derived from Fedora, right now a Fedora 43 snapshot, rather than assembled package by package the way 1.0 through 3.0 were."

And if you are still unsure. Checkout the repo:

* <https://github.com/microsoft/azurelinux>

or more specifically, the releases

* <https://github.com/microsoft/azurelinux/releases>

Surprised it doesn't have Copilot in the name somewhere

Previously (61 points, 17 days ago, 49 comments) https://news.ycombinator.com/item?id=48187736

Microsoft's Azure Linux (66 points, 4 months ago, 109 comments) https://news.ycombinator.com/item?id=46805841

Read the article. MS have shipped 1.0-3.0 earlier...

"Azure Linux 4.0 is derived from Fedora, right now a Fedora 43 snapshot, rather than assembled package by package the way 1.0 through 3.0 were."

And if you are still unsure. Checkout the repo:

* <https://github.com/microsoft/azurelinux>

or more specifically, the releases

* <https://github.com/microsoft/azurelinux/releases>

Microsoft was a *nix supporter from the very beginning, with Microsoft Xenix.

[laughs in Torvalds.]

Tldr a MSFT maintained fedora fork tuned for Azure hardware.

No it's not. It's for tuned for Azure. Nobody is running this outside of their compute environment.

Yeah, a general purpose distro would come with a desktop environment and you'd be able to run it on your PC as your main OS. Calling this general purpose is so misleading.

Of course describing reality in titles would have the inconvenience of causing fewer clicks to these articles.

The title on HN could be updated though.

You point to a better timeline. Sometimes—when desperately alone—I imagine.

If only the guy who was destined to close a disk operating system deal with IBM hadn’t been goofing around with his plane that fateful day.

We would all be using lisp machines, running smalltalk on microkernels that put the HURD to shame. Just imagine: instead of backslashes and drive letters, we’d have parens. Endless, syntactically-valid parens.

Or CP/M, probably that. But can it run doom?

I was curious to see what it would be like to run this under WLS. I'm guessing we'll get our chance at some point.

You may be right, its possible however that people running on Azure may use it locally for testing.

I don’t know really. Amazon AL2023 can be used outside aws for example, and people might want the same distro on-prem as the cloud.

It’s not the average joe/jane though.

call me old fashioned isn't a general purpose OS one that runs on any hardware and set up? and is certified with hardware vendors for full backing and support?

all this says is: "MS now provides a unified Linux from WSL to the MS cloud. just like what you got w/ SUSE RH canonical up to now. but without any support outside the MS stack.", right?

or am I missing something?

Don't worry you aren't. Luckily no one will use this distro day to day

I'd say old fashioned Linux would come without any certification or support.

I fell like this could be a move to purposefully mislead and confuse "Normies" of what to expect from "general purpose Linux" means.

ISV certification is coming.

On-prem hardware support would be interesting, wouldn't it?

AFAIK it isn’t a declared term my left shoe is my first general purpose operating system, if i toss an esp32 in there i can probably call it linux too.

Moving from tdnf to dnf5 is interesting. Most internal platforms get more bespoke over time, not less.

Even the LLM bot accounts are struggling to find something interesting about this.

Christ, they even lead with AI slop.

Do people not realize that this just instantly torpedoes credibility and respect? I'm dumbfounded.

How desperate is Microsoft right now? Their model website was trying hard to be Anthropic, now they claim they have a linux distro? Which is just a tuned version?

What's next?

> now they claim they have a linux distro?

They have had a linux distro for a while, this one is at least 6 years old. They used it for container workloads, including those visible to client like AKS.

It seems with 4 they are using Fedora underneath.

Xenix was microsoft's. If you do ctrl-alt-f2 (to f7), you have Microsoft to thank

What advantages does Azure Linux have compared to Ubuntu?

It's from Microsoft. Many companies love to be very tightly tied to Microsoft, for some reasons. I never really understood the actual underlying reasons. Perhaps Windows 95 was that good and it's brand loyalty since.

Embrace, Extend, Extinguish anyone? Although, as a Fedora user I'm happy it's RPM based.

Little harder to pull that off when the key components are all GPL licensed, but also all of Microsoft's bits and pieces for their distro seem to be MIT Licensed. Honestly, it certainly feels more like Google lives by Embrace, Extend, Extinguish (email, browsers, video streaming, etc).

Not really. They've always advertised it for, well, Azure, and the actual announcement[0] makes it clear that it's simply a distro for Azure workloads. Considering they state it's "built exclusively for cloud and server workloads, it is not intended to support desktop usage or GUI applications," Microsoft isn't playing that game here.

[0] https://techcommunity.microsoft.com/blog/linuxandopensourceb...

As a Fedora hater, I'm also happy it's RPM based; IMO, .debs are just flat out worse than .rpm as a format and the tooling on top matches that. I do wonder, though:

> Azure Linux 4.0 is derived from Fedora, right now a Fedora 43 snapshot, rather than assembled package by package the way 1.0 through 3.0 were.

Then what's the point? They could just ship Fedora. There are minor differences, but all things that sound easy to get upstreamed with minimal effort.

Extinguish Windows morelike...

This is a nonevent, unless perhaps some genuine "general purpose" tools come out of this. MS will never contribute to things such as Wine and Proton and kill its golden goose.

You say that, but Microsoft has contributed to Wine!

Both in terms of code and help, on occasion. Microsoft gave Mono to Wine, and while Wine has a ban on accepting code from people who have seen the source of Microsoft Windows, they have, if I recall correctly, accepted documentation on Windows Internals from Microsoft themselves.

Technically they gave mono to the wine project

>MS will never contribute to things such as Wine and Proton and kill its golden goose.

I think Microsoft is contributing to Linux kernel. Their golden gooses are Azure and Office which have nothing to do with Wine and Proton.

It wouldn't be too weird if they will release a win32 compatibility layer for Linux in the future as they might not want to maintain a full operating system.

You may be right, its possible however that people running on Azure may use it locally for testing.

I don’t know really. Amazon AL2023 can be used outside aws for example, and people might want the same distro on-prem as the cloud.

It’s not the average joe/jane though.

Don't worry you aren't. Luckily no one will use this distro day to day

I'd say old fashioned Linux would come without any certification or support.

I fell like this could be a move to purposefully mislead and confuse "Normies" of what to expect from "general purpose Linux" means.

ISV certification is coming.

On-prem hardware support would be interesting, wouldn't it?

You say that, but Microsoft has contributed to Wine!

Technically they gave mono to the wine project

>MS will never contribute to things such as Wine and Proton and kill its golden goose.

I think Microsoft is contributing to Linux kernel. Their golden gooses are Azure and Office which have nothing to do with Wine and Proton.

It wouldn't be too weird if they will release a win32 compatibility layer for Linux in the future as they might not want to maintain a full operating system.

DeathArrow also touches on this, but to complete:

Windows stopped being the Golden Goose a long time ago, probably from the point Satya Nadella became CEO.

A visual aid from a quick search: https://visuwire.com/microsoft/

For instance Bing and LinkedIn combined bring in more than Windows at this point. And XBox is basically on par.

Their money makers don't rely on Windows either, so the OS isn't even a useable moat, which is why they can afford to enshittify the consumer version to death.

[Edit: fixed the CEO name]

I don't think Microsoft would intentionally compete with Windows, but it does seem as though they are preparing for a world where Windows is no longer their golden goose, or at least hedging their bets. Given that Windows has already decisively lost the battle for servers, this seems prudent.

Yeah, a general purpose distro would come with a desktop environment and you'd be able to run it on your PC as your main OS. Calling this general purpose is so misleading.

Of course describing reality in titles would have the inconvenience of causing fewer clicks to these articles.

The title on HN could be updated though.

According to [1] the guidelines explicitly say to keep editorializing to a specified minimum, unless it is spam. Dont know it this title would allow editorialising

[1] https://news.ycombinator.com/newsguidelines.html

You point to a better timeline. Sometimes—when desperately alone—I imagine.

If only the guy who was destined to close a disk operating system deal with IBM hadn’t been goofing around with his plane that fateful day.

Or CP/M, probably that. But can it run doom?

Sorry to break it to you, but on that timeline, the good things got poisoned. IBM enhanced Lisp with Enterprise Ready features like Spreadsheet Macro Builder, Microsoft took over development of Smalltalk and morphed it into BASIC 2.0, and the HURD community lost a bizarre copyright lawsuit. Fortunately for those folks, an intrepid hacker in the 90s saw some of the interesting ideas in MS-DOS and rebuilt it as LS-DOS. Today, most of their servers and mobile phones run LS-DOS or similar.

Glad that at least we avoided that much more parentheses.

Where is our PL any kind of bracket and other rococo ornamental symbol is at most totally optional?

I was curious to see what it would be like to run this under WLS. I'm guessing we'll get our chance at some point.

You get a sense of it now. Azure Linux 3.0 is the base for the WSL system distro, there all the WSLg (GUI) and now the wslc plumbing happens. It's ephemeral, but you can drop in and look around with wsl --system --user root. An official WSL image of Azure Linux 4.0 is coming in a few weeks that you'll be able to install with wsl.exe --install Azure...(I'm not sure the exact name).

According to [1] the guidelines explicitly say to keep editorializing to a specified minimum, unless it is spam. Dont know it this title would allow editorialising

[1] https://news.ycombinator.com/newsguidelines.html

Glad that at least we avoided that much more parentheses.

Where is our PL any kind of bracket and other rococo ornamental symbol is at most totally optional?

Even the LLM bot accounts are struggling to find something interesting about this.

AFAIK it isn’t a declared term my left shoe is my first general purpose operating system, if i toss an esp32 in there i can probably call it linux too.

> now they claim they have a linux distro?

They have had a linux distro for a while, this one is at least 6 years old. They used it for container workloads, including those visible to client like AKS.

It seems with 4 they are using Fedora underneath.

Xenix was microsoft's. If you do ctrl-alt-f2 (to f7), you have Microsoft to thank

[0] https://techcommunity.microsoft.com/blog/linuxandopensourceb...

Extinguish Windows morelike...

Which is rather kind.

They could of also pulled an Oracle , claimed the APIs are copyrighted and sued.

WINE, even if right couldn't afford to fight.

I can even imagine official Linux support for the Surface tablets.

Infact, Microsoft makes very little off its consumer OS. They could even give up the market entirely and bless a distro with solid WINE support for legacy applications.

DeathArrow also touches on this, but to complete:

Windows stopped being the Golden Goose a long time ago, probably from the point Satya Nadella became CEO.

A visual aid from a quick search: https://visuwire.com/microsoft/

For instance Bing and LinkedIn combined bring in more than Windows at this point. And XBox is basically on par.

Their money makers don't rely on Windows either, so the OS isn't even a useable moat, which is why they can afford to enshittify the consumer version to death.

[Edit: fixed the CEO name]

Sundar Pichai does not work in Microsoft, though. A bit weird to anchor the MS timeline on his position. When he became the CEO, actually? I don’t remember the year even approximately

It’s already no longer their golden goose. It’s about 6% of total revenue (see http://bullfincher.io/companies/microsoft-corporation/revenu...).

Microsoft could give Windows away for free and be fine. Of course it’s still a lot of money, so they’re not going to leave a multibillion dollar business on the table. But strategically, preserving its revenue is not their priority.

LSD-OS would be an AI core unsupported by runtime and operating system that cascades streams of consciousness in a portable cartridge smartphone form factor until mounted on an embodiment to become unified and coherent.

Do people not realize that this just instantly torpedoes credibility and respect? I'm dumbfounded.

Did Microsoft have credibility and respect? They've been abusive towards their users for decades.

Because someone has to be accountable, right? In business practices, having no clear party responsible for an area you don't fully understand is a difficult problem. Ultimately, I think it's a matter of accountability. Regardless of how lightweight and good Linux is, Windows is still a bit more convenient on the GUI side.

You cited three of the most prominent counterexamples to the common meme about Google killing their products as evidence of them extinguishing things. I'm not saying you're wrong necessarily, but I don't think you've demonstrated what you think you have.

Agreed on the Google front here.

That's why they're pushing hardware attestation so aggressively

As a Fedora hater, I'm also happy it's RPM based; IMO, .debs are just flat out worse than .rpm as a format and the tooling on top matches that. I do wonder, though:

> Azure Linux 4.0 is derived from Fedora, right now a Fedora 43 snapshot, rather than assembled package by package the way 1.0 through 3.0 were.

Then what's the point? They could just ship Fedora. There are minor differences, but all things that sound easy to get upstreamed with minimal effort.

Same as with any distribution it gives you flexibility over update cadence, validate your software doesn't break with updates, and push out your own hotfixes without being tied to the release process upstream.

Default configurations as well, since it states FIPS compliance it has to change defaults <https://fedoraproject.org/wiki/Changes/RemoveFipsModeSetup#W...>

Time difference. A VP at Microsoft has someone they can yell at to make an ship a change. Having to ask upstream politely and then wait for their release schedule was proving to be an issue.

Did Microsoft have credibility and respect? They've been abusive towards their users for decades.

Agreed on the Google front here.

That's why they're pushing hardware attestation so aggressively

Default configurations as well, since it states FIPS compliance it has to change defaults <https://fedoraproject.org/wiki/Changes/RemoveFipsModeSetup#W...>

Time difference. A VP at Microsoft has someone they can yell at to make an ship a change. Having to ask upstream politely and then wait for their release schedule was proving to be an issue.

Which is rather kind.

They could of also pulled an Oracle , claimed the APIs are copyrighted and sued.

WINE, even if right couldn't afford to fight.

I can even imagine official Linux support for the Surface tablets.

Infact, Microsoft makes very little off its consumer OS. They could even give up the market entirely and bless a distro with solid WINE support for legacy applications.

> They could of also pulled an Oracle , claimed the APIs are copyrighted and sued.

They did, well - not the suing part, but everything else in your sentence; including helping Oracle "pull an Oracle". In 2013, Microsoft filed an Amicus brief in support of Oracle's[1] position, appealing against a judges ruling that APIs cannot be copyrighted. At the time, Microsoft were also trying to get an Android-compatible runtime on Windows off the ground, which was incredibly awkward. They came to their right mind by the time 2019 rolled by and the case had been appealed to the Supreme Court. At this occasion, Microsoft switched teams and filed an amicus in support of Google. I don't know if Microsoft's 2016 release of WSL had anything to do with it.

1. https://arstechnica.com/tech-policy/2013/02/microsoft-forese...

Sundar Pichai does not work in Microsoft, though. A bit weird to anchor the MS timeline on his position. When he became the CEO, actually? I don’t remember the year even approximately

Pretty sure he meant Satya Nadella but picked the wrong name...

Sorry it was a brain fart. I meant Satya Nadella.

It’s already no longer their golden goose. It’s about 6% of total revenue (see http://bullfincher.io/companies/microsoft-corporation/revenu...).

How many percent of their revenue funel are dependent directly or indirectly on windows beeing the peoples workstation funneling them towards their subpar ptoducts?

The “extinguish” part refers to your competition, not to your own product.

You embrace a popular open standard, add new features to your software that build upon the standard (but are proprietary), then watch as your competitors die off because customers become locked into your proprietary features.

Similar to how Apple hijacked SMS to add iMessage and introduced all kinds of features and the blue/green bubble styling.

For the longest time, they refused to support RCS, trying to keep people on iPhone by making texting between iOS and Android suck.

Of course, a lot of people switched to third party messaging apps because of how much Apple was intentionally ruining texting, so now Apple has had to adopt RCS.

So the “extinguish” part can be hard to pull off given sufficiently strong competition.

> They could of also pulled an Oracle , claimed the APIs are copyrighted and sued.

1. https://arstechnica.com/tech-policy/2013/02/microsoft-forese...

Pretty sure he meant Satya Nadella but picked the wrong name...

Sorry it was a brain fart. I meant Satya Nadella.

Ah, okay, my bad. Got too focused on the name. Googled the dates, Satya became CEO in 2014 and Sundar became CEO in 2015, so it’s actually not that different, especially when we look at the events more than a decade later.

How many percent of their revenue funel are dependent directly or indirectly on windows beeing the peoples workstation funneling them towards their subpar ptoducts?

Probably some amount. I agree Windows is strategic, but do definitely could see them giving it away and/or fully open sourcing it.

The “extinguish” part refers to your competition, not to your own product.

Similar to how Apple hijacked SMS to add iMessage and introduced all kinds of features and the blue/green bubble styling.

For the longest time, they refused to support RCS, trying to keep people on iPhone by making texting between iOS and Android suck.

Of course, a lot of people switched to third party messaging apps because of how much Apple was intentionally ruining texting, so now Apple has had to adopt RCS.

So the “extinguish” part can be hard to pull off given sufficiently strong competition.

Probably some amount. I agree Windows is strategic, but do definitely could see them giving it away and/or fully open sourcing it.

Linux

Microsoft’s in-house Linux, the distribution that grew out of CBL-Mariner, just hit public preview as a general-purpose cloud OS you can run on any Azure VM and coming soon to WSL.

Azure Linux 4.0 is Microsoft’s first general-purpose Linux

Microsoft shipped Azure Linux 4.0 into public preview at Build 2026, and for the first time you can run it on any Azure virtual machine, not just as the host underneath Azure Kubernetes Service. That sounds like a small distinction. But, this is the moment Microsoft's in-house Linux stops being a special-purpose appliance distro and becomes a general-purpose Linux distro.

I have been following this distribution since before it had a marketing name. So let me put 4.0 in context...

Photos from the Azure Linux 4 session at Microsoft Build 2026

What I keep on about

Microsoft has built more than one Linux distribution. Back in February 2022 I went looking through Microsoft's package mirrors and found CBL-Delridge, a Debian-based distro that powered Azure Cloud Shell. It was never announced. Mary Jo Foley wrote it up at ZDNet after reading that post. By November 2022, Delridge was 404: its apt repository went dark and Cloud Shell moved to Microsoft's other Linux: CBL-Mariner.

CBL stands for Common Base Linux, a whole family of internal distros named after Seattle geography. Delridge was the Debian one. Mariner was an RPM one, built from scratch with spec files borrowed from Photon OS, Fedora, and Linux From Scratch. Mariner is the one that survived. In March 2024 Microsoft renamed it Azure Linux and renamed the GitHub repository to match.

So when I say Azure Linux, I mean the distribution that started internal development in September 2019, went public on GitHub in November 2020, hit 2.0 in April 2022, and has been the container host for AKS since 2023. None of that history was aimed at you running it on your own VM.

That is what changes now.

What is actually new in 4.0

Azure Linux 4.0 is derived from Fedora, right now a Fedora 43 snapshot, rather than assembled package by package the way 1.0 through 3.0 were. Microsoft no longer maintains every spec file by hand. Instead it tracks Fedora upstream and applies declarative overlays, where every deviation from Fedora carries a written description of why it exists. The rendered spec files are checked into the repository so you can read exactly what Microsoft changed and why.

The component stack moved up accordingly:

Kernel 6.18 LTS, Azure-tuned, with the Hyper-V integration and GPU and AI accelerator support you would expect from an Azure cloud kernel. Microsoft maintains its own kernel fork and embeds its signing keys directly in the build.
dnf5 replaces tdnf, Microsoft's lean C reimplementation of dnf inherited from Photon OS. This is the single most user-visible change. You now get standard dnf5 tooling and the full plugin ecosystem instead of a Microsoft-specific package manager.
glibc 2.42, systemd 258, OpenSSL 3.5 (with post-quantum cryptography support), Python 3.14, and RPM 6.0 with a modernized database backend and stronger signature verification.
FIPS 140-3 certification is in progress and slated for general availability.

Security is solid. SELinux is supported on every image, the kernel ships with hardening turned on (ASLR, stack protection, seccomp, and systemd service sandboxing), packages and repositories are cryptographically signed, and Microsoft publishes SBOMs for the supply chain.

Why this is the next step

Here is the part that matters. For most of its life, Azure Linux was infrastructure you ran on without knowing it. It was the host OS for AKS nodes, the base image for Microsoft's own first-party services, the system distro that hosts WSLg. You did not pick it. It was underneath the thing you picked.

Azure Linux 4.0 is built to be picked. It runs across every Azure compute surface:

Virtual machines and scale sets, deployable straight from the Azure Marketplace with no additional OS licensing cost.
Containers, with base, distroless, and language-runtime images on the Microsoft Container Registry, built from the same supply chain as the VM images.
AKS, where it has been the container host since 2023, now joined by Azure Container Linux, a Flatcar-based immutable variant that shares the same kernel for stricter compliance environments.
WSL, so you can develop locally on the same Linux you deploy to production with wsl --install -d AzureLinux (soon, go try it on Azure first).

Databricks migrated more than 100,000 VMs and over a million CPU cores to Azure Linux. LinkedIn moved its infrastructure to Azure Linux. Azure Linux already runs behind AKS, Azure SQL, and Cosmos DB. The 4.0 preview takes that and gives it to everyone else.

What makes Azure Linux different

There are a lot of cloud Linux distributions. Amazon has Amazon Linux. The Flatcar and CoreOS lineage offers immutable container hosts. Ubuntu and RHEL run nearly everywhere. So what is distinct here?

A few things stand out:

The supply chain is auditable by design. Building on Fedora with declarative overlays means every change from upstream is documented in the repository. That is a stronger story than most distributions can tell about what is in their packages and why.
It is minimal on purpose. Azure Linux ships only what cloud and server workloads need. There is no desktop, no GUI, no general-purpose sprawl. The distroless container images take this to its logical end: no shell, no package manager, almost nothing to exploit.
Microsoft made a Linux distro.

What it means for Linux

I have tracked Microsoft's open source arc for years. The short version: Azure started hosting Linux VMs in 2012, Satya Nadella said "Microsoft loves Linux" in 2014, Microsoft joined the Linux Foundation in 2016, shipped WSL the same year, cross-licensed 60,000 patents through the Open Invention Network in 2018, and by 2019 Linux was the majority operating system on Azure. Today more than two-thirds of customer cores on Azure run Linux.

Against that backdrop, a general-purpose Azure Linux is the logical next step. Microsoft went from consuming Linux, to shipping Linux internally, to shipping a Linux distribution anyone can run.

Another major vendor maintaining a distribution upstream-first against Fedora, contributing patches, and putting real money into supply-chain security work through OpenSSF and Alpha-Omega. More maintained distributions, built in the open, is good for everyone downstream.

From an undocumented Debian remix I had to reverse-engineer from a package mirror, to a Fedora-derived, FIPS-targeted, distroless-capable distribution you can deploy from a marketplace in two clicks. That is a long way in four years.

Microsoft ships Linux.

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