Subiquity sometimes fails to do the post-install reboot on focal/amd64

Bug #1914285 reported by Paride Legovini
This bug affects 2 people
Affects Status Importance Assigned to Milestone

Bug Description

Starting with the 2021-02-01 ubuntu-focal-live-server-amd64 images subiquity sometimes fails to trigger a reboot when the install is done, at least when installing in a libvirt/qemu VM. The VM gets stuck at "Failed unmounting cdrom" (which is normal), see [1]. Normally the process continues with the printouts [2] and the VM reboots, but with the latest images this doesn't happen anymore about 1 time out of 3.

Reproducer via preseeded install (answers.yaml):

1. mkdir /tmp/isofail ; cd /tmp/isofail
2. download [3] and [4]
3. download the latest focal-live-server-amd64.iso
4. qemu-img create -f qcow2 disk0.qcow2 8G
5. virsh create fail.xml

Try this a few times and you should hit the reboot hang. Note: the VM gets undefined at shutdown so on "success" (bug not reproduced) it will just disappear. Just try the same command again.

This happens with a host system on Bionic, Bionic + cloud archive, Hirsute.

I could *not* reproduce it with a bare kvm/qemu install like:

kvm -m 2048 -boot d -cdrom ./focal-live-server-amd64.iso -drive file=disk.img,if=virtio -drive file=answers-utah.img,if=virtio

This command results in an install loop (the cdrom is never removed) that never got stuck in my testing.


Revision history for this message
Ubuntu QA Website (ubuntuqa) wrote :

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:

tags: added: iso-testing
Revision history for this message
Paride Legovini (paride) wrote :

This XML defines the VM in BIOS mode. They behave the same.

tags: added: fr-1107
Revision history for this message
Paride Legovini (paride) wrote :

For some reason this doesn't seem to be happening anymore. I'm setting the bug status to Incomplete for now.

Changed in subiquity:
status: New → Incomplete
Revision history for this message
Launchpad Janitor (janitor) wrote :

[Expired for subiquity because there has been no activity for 60 days.]

Changed in subiquity:
status: Incomplete → Expired
Revision history for this message
Paride Legovini (paride) wrote :

I'm fine with the expiration, I didn't hit the issue anymore.

Revision history for this message
Julio Lajara (ju2wheels) wrote :

Im having this same problem for both 20.04 and 22.04 but only with Virtualbox and not qemu/libvirt.

It makes it all the way through the late commands and then when it goes to reboot it has all sorts of file system I/O issues and doesnt complete the reboot.

The boot loop the original poster describes above is expected because of the use of EFI (you need to use efibootmgr to change the device boot order manually in the late commands since it cant automatically drop the use of the CDROM/ISO as the initial boot device).

I will attach screenshots of the errors I see from subiquity when its supposed to be restarting the instance.

Revision history for this message
Julio Lajara (ju2wheels) wrote :

subiquity failing to reboot, fs errors

Revision history for this message
Julio Lajara (ju2wheels) wrote :

subiquity failing to unmount cd/fs on reboot

Revision history for this message
Julio Lajara (ju2wheels) wrote :

OK, ive figured out how to reliably reproduce this issue. I am using Ubuntu 22.04 host, Virtualbox 7.0.6 with the extension pack.

Create an instance in Virtualbox that is configured to use UEFI BIOS and also enable x2apic (I dont know if you can do this in the GUI, but on the commandline its VBoxManage modifyvm <vm_uuid> --x2apic on`).

Boot the instance into 20.04 or 22.04 live server image and attempt to do an autoinstall by whatever method you choose.

With x2apic enabled, the subiquity install hangs on completion reboot 100% of the time with the errors referenced above for both 20.04 and 22.04 using the latest subiquity via updating as of today. If you disable x2apic, then it all works perfectly fine and autoinstall succeeds and reboots the instance ok.

Im not sure if I should just open this a separate ticket that specific outlines x2apic as problematic or not, so ill leave it here for now.

Revision history for this message
Julio Lajara (ju2wheels) wrote :

Updating the status to not expired since I have added an avenue that reliably reproduces the issue.

Changed in subiquity:
status: Expired → Confirmed
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