Azure does run on Windows. It's HyperV server below the rest of the hardware. It's a custom Windows install that you can't purchase, but it's Windows none the less.
That's interesting. Do you have a public source for this handy?
I remember seeing an article [1] proclaiming that more than 50% of Azure's workloads are on Linux, so I'm guessing their hypervisors are running an optimised Linux kernel somewhat.
1: Linux is Most Used OS in Microsoft Azure – over 50 percent of VM cores
that 50% is the guests, not the hosts... I think they even have Hyper-V, along with the Windows Server Kernel, running on ARM, since they now have ARM VMs... Only a matter of time before thats released in the wild... [1][https://azure.microsoft.com/en-us/blog/azure-virtual-machine...]
Azure Devops Services is an updated version of their old Team Foundation Server stuff. You can't create projects, teams, or workitem areas/iteration paths that are any of the microsoft magic names ( con, nul, ...etc... ), presumably because they store the data on a windows drive and it would implode. git repos, too, but that's just good planning for any git service since allowing microsoft reserved names would make the repo unclonable to microsoft systems.