I used to work for a quite “big” hosting company in Dublin, that claimed 1/3 of the Irish internet footprint was in their infrastructure. Over half of the servers we had in that infrastructure ran Linux, in particular the CentOS distribution. It was liked because it’s a relation of RedHat and … well … it’s free … and most hosting customers are pretty tight with their wallets. I’d really never heard of CentOS before that. As a hosting company we weren’t unusual for choosing CentOS for our Linux platform. In fact, it’s the norm because it is free.
We’ve had growing support for Linux on Hyper-V for a while but that was restricted initially to SUSE SLES (Novell, a partner of MSFT, and very unpopular in the market because of the NetWare abandonment) and RedHat RHEL (popular in the enterprise because you have to pay for it).
Over the last couple of years CentOS has come up more and more in conversations. I remember one very large “RFI” (a first step in the tender process) for a very large cloud (virtualisation environment) for a particular closed industry. In my last job we started reading that document with great anticipation – thinking about the huge numbers. But then our hearts sank: CentOS support was required. That ruled us out at the time. I know that other IT services companies were feeling the same way because I received a number of calls on the subject of Hyper-V/Linux support. I also know what official opinions in certain places were: this was no longer a Hyper-V opportunity and VMware would win it. CentOS may have run perfectly with the Linux integration components but the lack of an official support statement was impacting on potential sales & installations. And this is a huge factor in the decision making process for hosting (VPS/cloud/whatever-marketing-label-is-popular-at-the-time) companies who do favour CentOS over the paid for Linux distros that were previously the only supported open source OSs on Hyper-V.
But now we do have support for CentOS, according to an announcement on the Openness @ Microsoft blog. Now more enterprises and hosting companies can consider Hyper-V for their virtualisation and/or private/public cloud needs. There are no specifics such as version support, or how Microsoft will support an open source OS with no company being responsible for it. Hopefully that will emerge in the coming days.
One remaining lacking component is the System Center story. OpsMgr has made great strides in adding support for SLES and RHEL. Unfortunately they haven’t been in sync with Hyper-V so the common denominator of supported versions is quite small. Hopefully OpsMgr will add equal CentOS support quite soon. Let’s face it: the business really doesn’t care about the servers; they care about the services running on them, and quite a lot of those run on CentOS.
EDIT#1
I’ve been informed that CentOS 5.2 through 5.6 are supported now.