I'm still relatively new to Linux. My question is why wouldn't Fedora Server be considered an alternative for the CentOS diaspora? It seems a better fit than Debian to me.
Previous product I worked on required a supported RHEL/CentOS environment on which to install our product. Even with the six years or so of support, our customers would piss and moan every time we'd tell them that RHEL/Centos5 was hitting EOL and they'd need to upgrade their servers to Centos 6 or 7 to stay supported. Most of them wouldn't even entertain the idea of "upgrading": for them, business as usual was holding on to the existing OS as long as possible, then buying an entirely new server with the latest-greatest CentOS release freshly installed on it, and doing a data migration.
I can't even imagine the amount of headache we would have gotten if they needed to upgrade every two years.
Except when the update brings some kind of massive change. RHEL 6->7, for example, was when systemd became the norm, and so right around the time our customers started upgrading, I suddenly had the hot potato dropped into my lap of needing to convert 20 years' worth of our software's init.d scripts into systemd services.
CentOS releases were supported for something like 8 years, while Fedora releases a new OS every ~6 months. It does support up to 2 older versions with updates, but that means potentially breaking major upgrades every 6-18 months, compared to once every 8 years.
Debian, OTOH, has a much longer release cycle, and more of a reputation for moving like molasses, which for better or worse mirrors CentOS a bit more closely.
For people who this doesn't make sense, it's the timeline of the stack on top that drives the OS stability requirements.
If you work in heavily regulated industries, systems migrations and software development can be order-of-years.
Having a mandatory OS upgrade mid-development/deployment is not desirable.
It's a terrible way to develop, but when changes need to be documented in excruciating detail and signed off on by legal... sometimes it's just the way things are.
Why would it be a better fit, because of the package management?
Package managers are irrelevant. The relevant part is the quality, methodology of testing, existing written policy and technical requirements for the software. That you at the end deliver it in a deb, rpm or what have you, amounts to little.
Debian Stable (with its quality, Debian policy, testing, and stability of package major versions) is closer to CentOS. Fedora would be, as Debian Unstable, too fast moving for CentOS usecases.
I can't even imagine the amount of headache we would have gotten if they needed to upgrade every two years.