Not so long ago, Red Hat was about the only serious option for big enterprise customers seeking to make the move to Linux. Times have changed and Red Hat is no longer the only game in town. There are now three major enterprise ready Linux companies vying for corporate business: Red Hat, Canonical and SUSE -- or four if noncommercial CentOS is counted.

Red Hat, with its $2 billion in annual revenue, remains the top banana, and that's not likely to change anytime soon. Wall Street constantly frets about the company -- currently because of fears it's losing in the cloud -- but the apprehensions are misguided. It's true that Red Hat Enterprise Linux public cloud deployments aren't setting the woods on fire, with The Market Share showing about 18,000 instances of RHEL running on Amazon's Elastic Compute Cloud, far behind Ubuntu's 209,000 or Amazon Linux Amazon Machine Image at 88,000 -- not to mention Windows with 29,000.

There's more to the cloud than OS instances on AWS or Azure, however, and Red Hat is dominant as a solutions provider, both in the cloud and in data centers, especially in high stakes arenas like the building of customized open source hybrid clouds incorporating existing infrastructures. Red Hat focuses on the high end, with over 90 percent of Fortune 500 companies relying on its expertise.

Canonical has had surprising success with Ubuntu Server, which has become something of a superstar in the public cloud. Being a privately held company, there's no way of knowing for sure how well this is paying off in the pocketbook, but some figures I've seen suggest the company is now close to breaking even -- a major milestone for a company that's been on the losing side of the ledger since it was founded 13 years ago.

Until recently, the company seemed to be content to build it's enterprise business while avoiding Red Hat's bread and butter markets. That's changing, and the company is moving into direct competition in areas where Red Hat has traditionally dominated, with Ubuntu branded management tools for OpenStack and Kubernetes.

SUSE, at the turn of the century, was poised to be the Linux brand of the future for enterprise use. It had been around since 1992, and was the first Linux distribution to market itself to the enterprise. By 2000, it was considered by many to be the most stable and advanced version of Linux on the market and was being adopted for both server and desktop use. That changed in 2003 when it was bought by financially ailing Novell, which was hoping to reinvent itself as an open source company.

Since coming under the ownership of Attachmate in 2011, and then Micro Focus in 2014, the company has returned to relevancy by taking a slow and steady approach to re-establish itself. A deal cut last year between Micro Focus and HPE, in which SUSE acquired HPE's OpenStack and Cloud Foundry, has helped level the playing field through improvements to SUSE OpenStack Cloud. The company also stands to benefit from being named HPE's open source partner of choice for Linux.

CentOS, a freely available and Red Hat blessed clone of RHEL, technically isn't a commercial project. However, there are many third party vendors that not only offer reasonably priced support, but which use it as a platform on which to build solutions for SMBs. Its zero price tag also makes it a favorite for web hosting companies.

With Ubuntu continuing to up its game, and if SUSE's relationship with HPE pays off as it should, competition between these big three enterprise Linux players should continue to grow. Despite the added competition, however, expect Red Hat to continue to set the bar for the foreseeable future.