This article about migrating to a CentOS 7 /8 RAID mdadm array has a lot of info but I wanted to focus specifically on what newer versions of CentOS 7 require to boot mdadm and what changes are necessary on CentOS 7.8+
CentOS 7 / 8 mdadm RAID booting requirements
This assumes you are chrooting into an existing install or using it to get a new deployment ready. However, these steps can........