Beware that CentOS 8 is not yet supported by Virtualmin. There is a pretty major outstanding issue that I haven’t been able to resolve yet, that prevents Webmin from restarting reliably (which needs to happen pretty frequently). You will have problems using Virtualmin on CentOS 8 at this point.
But, there is a repo for it and I think most of the software is there (though we’re deprecating suexec support, and moving to only supporting php-fpm execution mode, so you’ll need to be aware of that).
I guess this is a quite old installation? If it were installed anytime after Virtualmin 6, it would have the new repos that have CentOS 8. Repos for new installs are under the /vm/6 subdirectory. e.g. http://software.virtualmin.com/vm/6/gpl/centos/8/x86_64/
You may want to just uninstall the old virtualmin-release and install the new one in that directory.
But, again, CentOS 8 is not supported yet. We won’t be able to help you with problems (because you will definitely have problems and they are all gonna be related to the one big problem we’re aware of…they will be minor problems, but they will be weird, and we won’t know how to guide you on fixing them).
Im just about to get a new server … was undecided about whether to choose centos 7 or centos 8 but if theres virtualmin/centos 8 problems ill get centos 7 installed. Must admit bit scared … previously using centos 6 … that was challenging enough.