Open Source Summit 2026: Microsoft, A Long Arc That Keeps Going with Open Source

I'm at Open Source Summit North America 2026 in Minneapolis this week, which is kind of a nice change since the event is in my backyard for once. But the bigger thing on my mind is that I'm here as a Microsoft employee, and that's a sentence I never thought I'd write.

If you'd told me 15 years ago that I'd be working at Microsoft, I probably would've laughed. I came up through Commodore, Mac, and Linux. I've been an open source advocate and contributor for a long time, did work on OpenNMS, spent years in environments where the answer to most problems started with a penguin. Back then Microsoft was kind of the antagonist in that story. Open source was the threat, and the idea of these two worlds working together felt pretty far off.

After the line died down at Brendan Burns ' book signing, I grabbed the chance to get my own book signed and tell him a bit of my story. For folks who don't know Brendan, he co-founded Kubernetes and is now a Corporate VP and Technical Fellow at Microsoft working on Azure cloud native open source. In his keynote earlier that day, he mentioned that this June will mark his 10 year anniversary at Microsoft, and he called this moment a real culmination of a lot of the work he and a lot of other people put in to bring open source forward inside Azure.

I got to tell him a quick version of my story. That I'd been a Linux and open source person for a long time, that I never thought I'd end up at Microsoft, and that people like him being there is part of what made it feel possible. He was generous about it, signed the book, and we kept the line moving. But standing there I kind of realized something. The shift inside Microsoft didn't happen because of a slide deck or a CEO memo. It happened because actual open source people went and worked there, and stayed, and did real work in the open.

Brendan also said something in his keynote that stuck with me. He said when he started at Azure 10 years ago, Linux was not the majority operating system on the platform, now it is. And this week Microsoft announced the public preview of Azure Linux 4.0 on Azure Virtual Machines and the general availability of Azure Container Linux. More than two thirds of customer cores in Azure now run Linux, and the platforms running Microsoft 365, GitHub, and ChatGPT all sit on Linux foundations. That's wild to think about.

The contribution story is what really sells it for me though. Microsoft Azure has been the largest public cloud contributor and the second largest contributor overall to CNCF projects for three years running. They're doing upstream work in Kubernetes, Helm, containerd, Istio, Envoy, OpenTelemetry, Cilium, the whole core of cloud native. And then there are the projects they actually started and donated, Dapr, KAITO, Radius, Headlamp, Flatcar, Copacetic, and a bunch more. The Azure Container Linux piece Brendan announced is built on Flatcar, which Microsoft donated to CNCF a while back. That's a real pattern, not a one off.

Postgres is a project I'm very familiar with. I've been using it in OpenNMS and elsewhere since the early 2000s, so this one really got my attention. Microsoft now ships the latest Postgres on Azure Database for PostgreSQL the same day the community releases it. Same day. That doesn't happen by accident, and it doesn't happen if you're just consuming the project. Microsoft has a team of committers and contributors who work full time on the open source Postgres project, contributing features, performance work, bug fixes, and security patches upstream. The Citus acquisition years ago was the start of that, but what it turned into is more interesting than the deal itself. They built a real Postgres engineering team that ships upstream and ships on Azure at the same cadence as the project.

Worth calling out too, the Azure Linux 4.0 work is built on Fedora as an upstream base. Microsoft says so directly in the project's GitHub README, though they didn't really lead with it in the Open Source Summit announcement. The README describes Azure Linux as a set of TOML configuration files and targeted overlays applied on top of Fedora, with packages coming straight from Fedora's upstream repositories. Same pattern as the rest of this. Work inside the existing ecosystem instead of forking off and doing their own thing.

Brendan isn't the only person who makes this feel real either. Bridget Kromhout , who's also based here in the Twin Cities, is a Principal Product Manager at Microsoft Azure focused on the open source cloud native ecosystem. She's been doing community work in Kubernetes, devopsdays, and the broader cloud native space for years. There are a lot of folks like her and Brendan at Microsoft, which is probably the real reason any of this is working.

I'm not saying everything is perfect or that there aren't still legitimate critiques. There always are. But the picture of Microsoft as some recent open source convert misses what's actually happened. This has been a long, steady arc, built by a lot of people doing the work in public, for years. Standing at that booth getting a book signed by a Kubernetes co-founder who works at Microsoft, as a new Microsoft employee myself who came from the Linux side, was honestly kind of a full circle moment.

Brendan's 10 years there is part of that arc. I'm just getting started on mine.

If you're at the summit this week, come say hi. I am occasionally hanging out at the Microsoft booth in between sessions.

#OpenSource #Linux #OpenSourceSummit #Microsoft #AzureLinux #PostgreSQL

#OpenSource #Linux #OpenSourceSummit #Microsoft #AzureLinux #PostgreSQL