[UBUNTU 20.04] Unsupported setup: Directory '/boot' is located on a multi-target device-mapper device

[bugproxy]

---Problem Description---
System Update did not work on Ubuntu 20.04.6 LTS. After apt update and apt full-upgrade came the following error message:
...
Calling hook copymods
/usr/share/initramfs-tools/scripts/panic/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/local-block/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/init-top/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/local-bottom/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/init-premount/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/local-top/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/init-bottom/ORDER ignored: not executable
/usr/share/initramfs-tools/scripts/local-premount/ORDER ignored: not executable
Building cpio /boot/initrd.img-5.4.0-150-generic.new initramfs
Using config file '/etc/zipl.conf'
Run /lib/s390-tools/zipl_helper.device-mapper /boot
Error: Unsupported setup: Directory '/boot' is located on a multi-target device-mapper device
Error: Script could not determine target parameters
run-parts: /etc/initramfs/post-update.d//zz-zipl exited with return code 1

But the error message is not true. Update used to work before. It is a KVM guest. The disk is a qcow2 file not multipath. There is no separate /boot partition. It is an ext4 file system.

Filesystems:
root@lnxproxy:/# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_bistro-lv_root 12G 8.4G 2.2G 80% /
/dev/mapper/vg_bistro-lv_home 28G 12G 15G 46% /home
udev 888M 0 888M 0% /dev
tmpfs 900M 12K 900M 1% /dev/shm
tmpfs 900M 0 900M 0% /sys/fs/cgroup

Contact Information = <email address hidden>

---uname output---
Linux lnxproxy 5.4.0-150-generic #167-Ubuntu SMP Mon May 15 17:35:14 UTC 2023 s390x s390x s390x GNU/Linux

Machine Type = zKVM guest

---System Hang---
 The system was not booting any more. I attached the disk to an other system.

---Debugger---
A debugger is not configured

---Steps to Reproduce---
 Run the command update-initramfs -uv.

*Additional Instructions for <email address hidden>:
-Post a private note with access information to the machine that the bug is occuring on.

[Julian Andres Klode (juliank)]

I think the warning comes because / is on an LVM logical volume, and there is no separate /boot partition. I would have expected there to be a separate /boot partition in such a case or does zipl have native lvm support?

[Frank Heimes (fheimes)]

@juliank yes, the msg (well, more an error than a warning) is about the LVM that is w/o separate /boot.

And that made me remembering LP#1680101, pretty old, but I think we carried over the thoughts from back then to the subiquity installer as well, that does create a separate /boot by default, in case LVM is used.
Looks like this (LVM with separate /boot) is the way we want and expect it (to be on the save side).

I think such an installation is not done by the installer by default.

@ppohl May I ask if you've done a manual installation (with root and boot in LVM).
And was you system already upgraded from an older release (maybe from 18.04 or even 16.04)?

My suspicion here is now that such a setup is just not a supported one (even if it might have once worked).

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2023-06-30 04:40 EDT-------
Yes, the server was upgraded from Ubuntu 18. As far as I remember LVM without a separate /boot partition was a default proposal for the file system layout.

[Steve Langasek (vorlon)]

Can we get a copy of /var/log/installer from the affected system?

[bugproxy (bugproxy)]

------- Comment on attachment From <email address hidden> 2023-07-10 05:53 EDT-------

I attached /var/log/installer directory