If you are using open-source Xen or KVM virtualization, we now have CentOS 7 images available for download. Just login to Cloudmin and go to Cloudmin Settings -> New System Images, search for CentOS 7 and download the one that matches your preferred virtualization type.
Both images include only the base distribution, so you will need to install Webmin or Virtualmin after creating a virtual system from them. Instead of XFS, both use EXT4 on the root filesystem for better compatibility with host systems that don’t support XFS.
Please note that a 64-bit host system is needed to run these images, as CentOS no longer supports 32-bit installs.