Seems like great news but I wonder if these releases help the .NET ecosystem in a meaningful anyway. Almost all .NET developers I know still use Windows even on cloud.
We maintain container images for both Linux and Windows. I can tell you that they both get a LOT of use (>10M pulls/month). .NET is very much a cross-platform app stack. Also, we get plenty of bug reports on Linux (which we diligently fix). The days of .NET being Windows-only (and closed source) are long over.
How much of that 60% is running .NET apps, though?
Not everyone who uses Azure is a "Microsoft shop", in terms of programming tech stack. Plenty of people use Azure as a cross-cloud redundancy play, or because they do business with Amazon competitors that refuse to have their data on AWS.
My understanding is that a growing percentage of that is .NET. Even "big corporate" realizes .NET Linux deployments on Azure are cheaper and are trying to cost-cut/cost-save. There's still a small feature parity difference in Azure between Linux and Windows servers, primarily in my experience in "no touch" Application Insights telemetry/logging for application state (and user) monitoring as a major one. If that feature gap closed I expect that 40% to drop rapidly in Azure simply for cost cutting reasons. Anecdotally, I've been feeling internal pressure in my company to move .NET deployments to Linux servers for cost savings and we've done some initial trial balloons on the engineering effort for working around that feature gap.
I met a guy a while back who did stints for both Amazon and Azure orgs.
It's the reverse in AWS, they have a bit more Windows market share than Linux. And he also backed up your statement.
His take (which was just his speculation) was that the virtualization stacks ran those OS's more efficiently. HyperV with Linux VM's and KVM with Windows VM's. I have no idea if that's true or not.
I work in games so it's Unity C# (which uses a Mono port but .net 6 'soon') and a backend that uses .net in a linux container. Using C# on both makes it easier for devs to work full stack. It's been easy to run the backend app in k8s.
I've been developing ASP.NET Core Apps on Windows since 2017 (when .NET Core support was added to our FX) and have created & deployed >50 .NET Apps exclusively to Linux, primarily Ubuntu so this is a welcomed announcement.
.NET definitely has first-class support on both Linux and Windows.
I've shipped .NET applications in organizations where adding Windows hosts never would have been contemplated, but adding a new application framework that ran on our standardized Linux environments was no big deal. Ops folks are often much warier about adding heterogeneous compute environments than they are about adding new application architectures, so an easier onboarding process for Linux shops experimenting with .NET could plausibly drive adoption.