[Users] Cannot add another host to "all-in-one" datacenter

Hello all, I installed an oVirt datacenter via "all-in-one" plugin, which means everything currently runs on one machine. I would like to add another host to this datacenter, it has it's own storage for virtual machine images, but oVirt refuses to add it with error "Cannot add more than one Host to "Local Storage" Data Center". Is it possible to configure this somewhere and add the host to the local_datacenter? Thank you in advance for response. Regards, Adam