Local Admin rights on a Domain Controller


I have a question regarding user permissions to take backups of Domain controllers. I followed the forum post  Account permissions needed for protecting machine? and that works great for non DC servers.  But now I need to get the DC connected with the NON domain Admin account.  On DC's there is no local administrators group, and I do not want to give this account domain admin privileges.  What permissions do I need to have to allow a full backup and will allow exporting of the VMs.