Installer reboot fails

Hello all. I’m new to discourse, so please give me guidance if I’m approaching this topic wrong.

I brought this issue up over in [ubuntu] Installer doesn't reboot: Failed unmounting cdrom.mount but haven’t really gotten very far in figuring out what needs to be done about it. Over the past couple of days, the issue has come up again as I wiped my home lab to put a fresh install of Ubuntu Server 24.04 on it. As noted in my forum post, this is not specific to a certain piece of hardware or a certain version of Ubuntu.

After completing the installer, for a few years I’ve noted the “[Failed]” message about ejecting a nonexistent cdrom when you select the reboot option on the last screen of the installer. Normally, it doesn’t cause any problems. But, more recently, I’ve noticed that it can cause problems. When using VMs, there are scenarios where the subsequent message about removing boot media and pressing enter are not displayed, and some of those scenarios prevent a graceful reboot.

When I installed Ubuntu Server 24.04 on my home lab base machine (twice, because I’m trying to test various things out), the installer reached the same old “[Failed]” message, but didn’t provide an option to remove the media and reboot. On top of that, I could not even do anything like Ctrl+Alt+Del, switching to an alternate terminal, or pressing the power button to get the machine to gracefully power off or reboot. I had to press-and-hold to do a hard power-off. The system was installed and the disks were unmounted, so no damage was done. But, this does not seem like “normal” behavior, even though I’m seeing these sorts of issues pop up at the end of the install regardless of the install environment. I’ve seen this in pretty much every install I’ve done, including bare metal on a workstation-turned-homelab, bare metal Dell servers, and virtualized in KVM (via virt-install), VirtualBox, and VMWare.

If I use a fully automated installer, it works fine. But if I’m doing any kind of manual install, then at a minimum a “[FAILED]” message is displayed, and in a worst case scenario the machine is unable to gracefully reboot. I’m running normal installs in normal environments. I can’t be the only person that has been seeing this, and I’ve been seeing it for multiple major version releases of Ubuntu. Is anyone else seeing this? Is there a rationale for it?