So I work for Red Hat and the truth is no one will know until after the acquisition, but there are certainly no plans for that, nor have I heard anyone even discussing such a thing. CentOS is a valuable part of Red Hat and an important part of keeping users in the ecosystem even if they're not paying us, so it wouldn't really make any sense. IBM aren't stupid (despite nonsense that people write online), and Red Hat is a cash machine and they'd be stupid if they messed with a proven model which works.

CentOS is being used by a lot of HPC shops, academia and research units like one where I administer a HPC.

For the number of cores that HPC shops run, the bill would become FAT real soon if we have to pay for OS. I'd imagine that if IBM messed with CentOS, it'd be called out for being incredibly dumb about RH business, and there would emerge an open fork of RHEL that is not owned by IBM like CentOS is.

To give you an idea, we run CentOS 7.5 on all compute nodes, but make use of paid for RHEL for our identity server, DB servers and the like. If IBM touches CentOS, the whole domino falls and we start looking for alternatives.

Regardless of who owns Redhat, they still have to provide the source RPM's for most of the packages. The best they could do is change the build format enough and often enough to make it painful to repackage.

I don't envision them doing this however. That would force a lot of people away from Redhat based distros and guarantee barring conversion to RHEL entitlements.

IBM has never struck me as that clueless about open source, and I imagine Red Hat management would fight that as much as possible realizing how much of a long term strategic blunder it would be.

From the people I know using huge amounts of centos in production, they're not going to pay for RHEL, if centos becomes non viable they'll be switching to debian-stable and debian-testing.

It would do damage to the brand, and then you'd see developers fork Fedora and build their own RHEL-like "enterprise Linux".