Comment by najeh for You can not use virtual box for compute But you can use virtual box for your controller In the lab you should use strong hardware for controller and small hardware for compute node but in operation it is diffrent

@novainfinite can i use physical machine for the for compute and contoller nodes installation to set up my private cloud. controller= physical machine1= 8 Gib ram / ubuntu-server OS compute= physical machine 2/3= 8 Gib ram /ubuntu-server OS