This week, Microsoft announced that it would support CentOS as a guest operating system on Hyper-V, citing CentOS support as the number one interoperability requirement among Web hosting providers weighting whether to consolidate their system virtualization on Microsoft’s hypervisor.

When I read the news, my thoughts turned immediately to Red Hat and its Red Hat Enterprise Linux operating system on which CentOS is directly based. I wasn’t alone–in a column in The Register, Matt Asay pointed out that the move might threaten Red Hat:

Despite repeated efforts, no other Linux vendor has come close to knocking Red Hat off its perch. Microsoft, in announcing support for CentOS, just may have taken a big step in that direction. The only competitor to cause Red Hat serious consternation is community Linux distribution CentOS.

For years, Red Hat has called out “unpaid Linux” as its chief competition, going so far as to report on “free-to-paid” deals on each quarterly earnings call.

I took the Microsoft support announcement to be positive development for Red Hat. After all, a bigger the pool of CentOS installations means more free-to-paid sales leads to chase down.

Every Linux OS ships with mostly the same code, but the implementation details from one distribution to the next differ enough to make switching between them non-trivial. It’s much better for Red Hat that CentOS–which faithfully tracks Red Hat’s codebase, but which lacks support from Red Hat–capture unpaid or “community” Linux share than if that share went to Debian, Ubuntu, or OpenSUSE.

By building its business on open source software, Red Hat does face a constant threat of being undercut by low or no-cost rebuilds of its flagship products, but Red Hat has experienced strong growth in the face of many such rebrands, including CentOS, Scientific Linux, and Oracle Unbreakable Linux. As long as Red Hat continues to deliver value for the fees it charges, it should manage to continue growing, in part on the backs of its community clones.

In my opinion, it’s an excellent situation for IT customers: Red Hat may be or become the Microsoft of Linux operating systems or the VMware of open source virtualization, but the company’s open source orientation leaves Red Hat little room for taking undue advantage of its dominance.