Centos 7 was released in 2014 and the support ends next week.
Debian 10 was released in 2019 and the support also ends next week.
Then make it longer. The debian team is starved for volunteers and would love to have more long term maintainers.
1. free/gratis Linux distribution
2. long support (~ 10 years)
3. not needing to contribute (as a community)
It seems that we can only pick two from this list (even a distribution with short support cycle needs community).
I mean, if they are using CentOS, apparently not.
Also, you can re-install a cattle worker node in 10 minutes or less, from power on.
For example, Debian has finished two big transitions recently. Merging /usr and 64 bit time support. Both are done on testing, and even on testing nothing has broken.
Another big change (which also made HN front page via LWN) was /tmp behavior change. It's handled differently. If your system is already installed, it doesn't change the behavior, but new systems will behave differently.
All of these changes are again communicated via "NEWS" mechanism. If Debian changes a config file, it's replaced. If you modified this file, apt will ask what you prefer, and you can diff the file in place.
In the past, many similar changes are made, and all were transparent. If you're not using any external repositories which change tons of system packages with their own versions, nothing changes during upgrades for you.
While there's an extensive release note provided with every release like [0], the upgrades are pretty straightforward.
As a result, having a few or many Debian systems which are older than a decade is a norm, not an exception.
[0]: https://www.debian.org/releases/stable/amd64/release-notes/
