As of last Monday, Microsoft supports CentOS as a guest operating system running on its Windows Server 2008 R2 Hyper-V hypervisor. It's not an earth-shattering piece of news, as its virtualization technology already supports two other flavors of Linux: SUSE Linux Enterprise Server, and CentOS's higher profile sibling, Red Hat Enterprise Linux. But the news is intriguing.
First, let's get the server virtualization jokes out of the way. "Running Linux in a VM on Windows is like strapping yourself to the outside of a car with a seatbelt," is how one wag commented on the news on slashdot.org. "So all the stability and security of Microsoft running on the bare metal; combined with the user-friendliness and ease of use of Linux. :)" commented another. And then there was: "Hosting an operating system with uptimes measured in hundreds of days on an OS that has to be rebooted every 45 days doesn't seem wise to me."
These comments are funny because, let's face it, they're true. But the big question, is why has Microsoft (NASDAQ: MSFT)added support for CentOS?
Sandy Gupta, Microsoft's general manager of marketing, Open Solutions Group, explained on a Microsoft blog that "CentOS is a popular Linux distribution for hosters, and this was the number one requirement for interoperability that we heard from that community." But it's really very hard to imagine that the future of hosting consists of virtualized CentOS running on Hyper-V.
If there really is huge pent-up demand from hosters to spend their cash on Microsoft's proprietary hypervisor so they can save money on Red Hat support costs by using CentOS instead of RHEL -- there's the answer. However, it's hard to not think there is more to it than that. After all, not many hosters are using Hyper-V for their hypervisor.
Another possibility is that the move is simply to make Hyper-V more attractive in the face of competition from the 400-pound proprietary gorilla in the virtualization space. VMware, in other words. Adding support for CentOS as a guest may not be a big deal, but when it comes to competing with VMware, it's better than not supporting CentOS.
Or maybe Microsoft's move is really an attack on open source software. At first glance, that doesn't seem likely: CentOS is open source, so how can supporting CentOS be construed as an attack on open source software? The explanation comes down to the fact that when it comes to open source alternatives to Microsoft's operating systems and hypervisor, the biggest competitor is Red Hat. By supporting CentOS as a guest, customers are quite possibly less likely to run RHEL as a guest, thus reducing the total amount of support fees that Red Hat gets from RHEL support contracts. This has the added benefit that CentOS is reliant on Red Hat, so what hurts Red Hat will ultimately hurt CentOS, helping to kill two pesky open source birds with one stone. Neat, eh?
If you don't go for that argument, how about the reverse? If Microsoft really is committed to interoperability between its own proprietary code and open source software, then maybe it introduced guest support for CentOS because that's the right thing to do ... No, I don't buy that one either.
So maybe we're barking up the wrong tree here, and there's another explanation altogether. An explanation, perhaps, that Gupta hints at in his blog posting when he talks about demonstrating "the cross-platform architecture of Microsoft's private cloud" using System Center, Microsoft's grand infrastructure management tool.
What this could really be about then is Microsoft flexing its muscles in the cloud computing space, and strengthening its hand in a bid to become the de-facto management system of choice for private cloud setups. Supporting CentOS would certainly do that. Gupta talks about using "a single pane of glass to deploy patches and updates across Windows and Linux servers," while Matt Asay over at the Register reckons Microsoft is "hoping to instill Microsoft's dashboards and management tools at the forefront of the user experience. The data center may be a morass of different components, but the trend is toward data-center-level APIs and virtualization. Microsoft wants to own these "choke points."
By supporting CentOS, in other words, Microsoft is happy to let you to strap yourself to the outside of cars with seatbelts. But if you run CentOS in a private cloud it reckons you'll be quite safe, all watched over by machines of loving grace running System Center.
Paul Rubens is a journalist based in Marlow on Thames, England. He has been programming, tinkering and generally sitting in front of computer screens since his first encounter with a DEC PDP-11 in 1979.