A query on the dependency between virtualbox VM and the ISO image attached at boot

[pv1973]

I am new to virtualbox. I have installed virtualbox on my Windows 10 laptop and created a Redhat 8 server VM. I would like to do further configurations on my VM such as adding a TFTP server et al., and also create another VM for Redhat 8 client and do similar additional configurations. But I have the following questions based on the standard procedure for booting VMs, which is by means of the ISO image:

i) Do the changes that we make to individual VMs remain persistent after the ISO image is detached?
ii) Since I am using the same ISO image for both client and server VMs, how are the changes in configuration for a server VM distinguished from those for a client VM inside virtualbox?

[mpack]

I have the following questions based on the standard procedure for booting VMs, which is by means of the ISO image

The ISO is the standard means of installing a guest OS to a local hard disk. Once the install is done the ISO is no longer needed, as the VM boots from and stores data to its local hard disk (virtual, in the case of a VM). Of course the ISO does need to contain a bootable image if you want to boot into an OS installer in an otherwise blank VM. Being bootable is not a requirement of ISO images in general.

[pv1973]

My experience is that each time you shutdown the VM, the ISO gets detached and the next time you need to start the VM, you need to attach the ISO again from within Settings->Storage->Controller IDE which shows Empty before attaching the ISO. So if the ISO is only needed for installation, which I presume is done for the VM, why is it that I need to attach the ISO every time to start the VM?

[scottgus1]

Check carefully that you're really installing the OS and not just LiveCD-testing the OS. Look up some videos on how to install your OS to a PC, do the same for a VM on any hypervisor.

In my experience, when running a true installation of a Linux OS, the ISO is not needed when the VM reboots. You're probably missing something in the install process.

If you truly feel you are installing, please write down exactly every step you are taking to install the OS. Maybe we might see something.

[mpack]

which I presume is done for the VM

Does that mean you think OS installation happens automatically? No.

A VM is no different from any other PC. Boot from the installer and follow the onscreen instructions to install the OS. Don't worry when you see warnings about previous contents of your drive being erased - it's referring to the virtual drive, which is already blank.