@SimonBM for RHCSA you would need 2 VMs whereas for RHCE I think you need 3 VMs ( 1 Control node , 2 managed nodes ) - 1-2 CPU, 4 GB RAM and 20GB storage should do the job perfectly fine.
You can use virt-mamager or you can use virtualBox - whatever suits you.
Keeping all your virtual machines on the same internal network is the easiest way to manage them. This lets your control node connect to each managed host using its IP address or hostname, just like it would in a real-world production environment.
To make this simple setup work well, first set each VM to use an internal network. Next, give each machine a static IP address for consistency. Then, update the /etc/hosts file on your control node to define names for each machine. Finally, be sure to set up passwordless SSH between your control node and all the managed hosts. This will save you a lot of time.
practice RHCSA or RHCE stuffs based on exam objectives.
