CentOS 7 -> 8 cluster incremental upgrade

Hi all,

I am considering upgrade of my cluster, currently based on CentOS 7, to CentOS 8. Can this be done without disrupting the running VMs? Are the scripts in remotes/ directory dependent on a system version? And also, should I upgrade the main node where the ONe daemons are running first, and then KVM nodes, or vice versa?

Also, should I do the upgrade with ONe 5.12, or migrate to 6.0 first?