CentOSのfork先は様々ですがAlmaLinuxを選択しました。Rocky Linuxからも移行でき汎用性があると判断しました。
以下はサイトより引用
Usage
In order to convert your EL8 operating system to AlmaLinux do the following:
Make a backup of the system. We didn’t test all possible scenarios so there is a risk that something goes wrong. In such a situation you will have a restore point.
Download the almalinux-deploy.sh script:
$ curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
Run the script and check its output for errors:
$ sudo bash almalinux-deploy.sh
…
Migration to AlmaLinux is completed
Ensure that your system was successfully converted:
check release file
$ cat /etc/redhat-release
AlmaLinux release 8.4 (Electric Cheetah)
check that the system boots AlmaLinux kernel by default
$ sudo grubby –info DEFAULT | grep AlmaLinux
title=”AlmaLinux (4.18.0-305.el8.x86_64) 8.4″
１０分ほどの更新作業で完了です。merge作業なくて簡単でした。secondary nameserverでしばらく運用して徐々に移行していきます。:-)