Color me surprised. I knew that Linux, while still only a niche player on the desktop, was continuing to do well on the server and was doing even better than ever on the cloud. What I hadn't realized was just how much better Linux, and in particular, Canonical's Ubuntu, was doing on in the market place.

Before I'd seen The Cloud Market's analysis of operating systems on Amazon Elastic Compute Cloud (EC2), off the cuff I would have guessed the leading operating system on the top cloud platform would have been Red Hat and its close relatives, CentOS, Oracle Enterprise Linux, and Fedora. Boy was I wrong.

Today, December 20th, Ubuntu is running 4,840 instances on EC2, followed by CentOS, with 1,250, Fedora with 313; Oracle with 80; and Red Hat with a mere 73 instances. That's a grand total of 1,716 for the Red Hat family, which means that Ubuntu is doing more than twice as well as all the Red Hat variants put together.

Windows and Azure? They're back in the back with a mere 1,120 instances.

Wow. I didn't see this coming. Of course, I knew that Canonical had been trying hard to become the number one Linux cloud company. I should. I broke the story that Ubuntu was going to try for the cloud brass ring back in 2009 with the help of Eucalyptus Systems, an open-source cloud infrastructure firm.

The result of that partnership explains a lot to me why Red Hat just partnered with Eucalyptus for its own clouds projects. Earlier this month, Red Hat acquired Makara, a start-up focused on providing a cloud platform for Java and PHP applications on both public and private clouds.

Red Hat has some ground to make up. Not only was in last place in the Red Hat family, Every Linux fan's favorite head-gear was also trailing Debian, with its 251 instances; SUSE Linux with 244, and-oh no!--even OpenSolaris is ahead with 80 instances.

Still, it's clear that Amazon's cloud is a Linux world. I find it telling that Amazon recently introduced its own Linux starter cloud using, guess what, "Ubuntu's CloudInit to simplify the process of customizing each instance. On the other hand, it appears to be, at heart, CentOS, so Ubuntu isn't having all its own way.

Of course, Amazon Web Services isn't the be-all and end-all of public clouds. Rackspace, which is leading the open-source OpenStack movement, is also a player. But, as Stephen O'Grady, one of the founders of RedMonk, a leading research firm, pointed out recently, Amazon Web Services (AWS) "is to the public cloud market what Microsoft is to operating systems or VMware to virtualization."

O'Grady concluded that "The fact is that Amazon, by hiding in plain sight, is building an impressive array of weapons with which they can attack a variety of customer and market types. In spite of this, they have attracted minimal attention." I might add that Ubuntu is doing the same as the operating system of choice, not merely the Linux of choice, for the cloud.