This is the only article I could find doing a quick search: https://www.wired.com/2015/09/microsoft-using-linux-run-cloud/ https://www.wired.com/2015/09/micros

This is the only article I could find doing a quick search: https://www.wired.com/2015/09/microsoft-using-linux-run-cloud/ https://www.wired.com/2015/09/microsoft-using-linux-run-clou... https://azure.microsoft.com/en-us/blog/microsoft-showcases-the-azure-cloud-switch-acs/ https://azure.microsoft.com/en-us/blog/microsoft-showcases-t... However, I could have swore I read semi-recently that Azure itself was primarily running on Linux, but I could be wrong here in some regards.