Ubuntu25.10: Ubuntu host installation is failing while doing installation on multiple[2 or more] multipath SAN disks!

[bugproxy]

== Comment: #0 - Anushree Mathur <email address hidden> - 2025-11-28 03:12:11 ==
ENV :
HOST OS : Ubuntu 25.10

Host installation is crashing with following crash when we do installation on multiple[2 or more] SAN disks and we see -EBUSY error with specific mpath disk.

generating crash report
report saved to /var/crash/1760429899.735880613.ui.crash
Traceback (most recent call last):
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/controllers/filesystem.py", line 296, in _guided_choice
    self.ui.set_body(FilesystemView(self.model, self))
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 485, in __init__
    self.refresh_model_inputs()
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 544, in refresh_model_inputs
    self.used_list.refresh_model_inputs()
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 417, in refresh_model_inputs
    for obj, cells in summarize_device(device, filter):
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/helpers.py", line 32, in summarize_device
    anns = labels.annotations(device) + labels.usage_labels(device)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/usr/lib/python3.12/functools.py", line 909, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/common/filesystem/labels.py", line 101, in _annotations_vg
    member = next(iter(vg.devices))
             ^^^^^^^^^^^^^^^^^^^^^^
StopIteration

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/snap/subiquity/6868/usr/bin/subiquity", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/cmd/tui.py", line 161, in main
    asyncio.run(run_with_loop())
  File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/base_events.py", line 687, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/cmd/tui.py", line 159, in run_with_loop
    await subiquity_interface.run()
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/client.py", line 426, in run
    await super().run()
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquitycore/tui.py", line 390, in run
    await super().run()
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquitycore/core.py", line 133, in run
    raise exc
  File "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/controllers/filesystem.py", line 300, in show_guided_and_redraw
    await self._guided_choice(choice)
RuntimeError: coroutine raised StopIteration
                                                                                                          ^[[29;1R^[[29;106R
Ubuntu Questing Quokka (development branch) ubuntu-server hvc

Explaining whole scenario:

When I tried to install my P11 lpar with Ubuntu with SAN disk
1) 4 SAN disks are there
2) I installed on mpatha (installation worked fine)
3) I installed on mpathb (installation worked fine)
4) When i rebooted the system connected to the console and then I tried to reinstall the system it gave the error message [-EBUSY] and then installation crashed

My analysis:

In the background, after each boot I was entering the shell and was checking for the multipath status:
1) In the first attempt when i checked it gave all four disks
2) After mpatha installation also all disks were listed in multipath -ll
3) After mpathb installation also all disks were there
4) When I tried the reinstallation after this I saw that multipath service itself gave the error as :

[2168]: updated bindings file /etc/multipath/bindings
[2168]: mpathb: addmap [0 230686720 multipath 1 queue_if_no_path 1 alua 2 1 ser>
[2168]: libdevmapper: ioctl/libdm-iface.c(1995): device-mapper: reload ioctl on>
[2168]: dm_addmap: libdm task=0 error: Device or resource busy
[2168]: mpathb: ignoring map
[2168]: mpathb: addmap [0 230686720 multipath 1 queue_if_no_path 1 alua 2 1 ser>
[2168]: libdevmapper: ioctl/libdm-iface.c(1995): device-mapper: reload ioctl on>
[2168]: dm_addmap: libdm task=0 error: Device or resource busy
[2168]: mpathb: ignoring map
: Started multipathd.service - Device-Mapper Multipath Device Controller.

5) With multipath -ll I was not able to see mpathb there
6) multipath service is not failing to restart but it is throwing this error message because mapping is not happening properly!
I feel because of some stale metadata present on the mapathb at the time of installation which shouldn't have been there, it has happened.

I tried this exact same scenario even on my P10 lpar which had 2 disks and I observed same kind of behavior!

Reproducibility with this exact scenario is 95%.
Reference bug is https://bugzilla.linux.ibm.com/show_bug.cgi?id=208604 but now the scenario has been changed!

[Frank Heimes (fheimes)]

... and I assume it's the same reason why I cannot connect to Launchpad via
the launchpadlib API

Error accessing Launchpad!
 (403, b'Forbidden')

On Mon, Dec 1, 2025 at 6:09 AM Launchpad Bug Tracker <
<email address hidden>> wrote:

> bugproxy (bugproxy) has assigned this bug to your team "Ubuntu on IBM
> Power Systems Bug Triage" for Ubuntu:
>
> == Comment: #0 - Anushree Mathur <email address hidden> - 2025-11-28
> 03:12:11 ==
> ENV :
> HOST OS : Ubuntu 25.10
>
> Host installation is crashing with following crash when we do
> installation on multiple[2 or more] SAN disks and we see -EBUSY error
> with specific mpath disk.
>
> generating crash report
> report saved to /var/crash/1760429899.735880613.ui.crash
> Traceback (most recent call last):
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/client/controllers/filesystem.py",
> line 296, in _guided_choice
> self.ui.set_body(FilesystemView(self.model, self))
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py",
> line 485, in __init__
> self.refresh_model_inputs()
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py",
> line 544, in refresh_model_inputs
> self.used_list.refresh_model_inputs()
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/filesystem.py",
> line 417, in refresh_model_inputs
> for obj, cells in summarize_device(device, filter):
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/ui/views/filesystem/helpers.py",
> line 32, in summarize_device
> anns = labels.annotations(device) + labels.usage_labels(device)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
> File "/snap/subiquity/6868/usr/lib/python3.12/functools.py", line 909,
> in wrapper
> return dispatch(args[0].__class__)(*args, **kw)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/common/filesystem/labels.py",
> line 101, in _annotations_vg
> member = next(iter(vg.devices))
> ^^^^^^^^^^^^^^^^^^^^^^
> StopIteration
>
> The above exception was the direct cause of the following exception:
>
> Traceback (most recent call last):
> File "/snap/subiquity/6868/usr/bin/subiquity", line 8, in <module>
> sys.exit(main())
> ^^^^^^
> File
> "/snap/subiquity/6868/lib/python3.12/site-packages/subiquity/cmd/tui.py",
> line 161, in main
> asyncio.run(run_with_loop())
> File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/runners.py", line
> 194, in run
> return runner.run(main)
> ^^^^^^^^^^^^^^^^
> File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/runners.py", line
> 118, in run
> return self._loop.run_until_complete(task)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> File "/snap/subiquity/6868/usr/lib/python3.12/asyncio/base_events.py",
> line 687, in run_until_complete
> return future.result()
> ^^^^^^^^^^^^^^^
> File
> "/snap/subiquity/6868/...

[Frank Heimes (fheimes)]

(please ignore comment #1, that was an accident)

Based on this bug I tried to recreate the case again, but still on a different platform.
So I setup a system with 2 SCSI LUNs attached via multipath,
and I was able to complete an installation of Ubuntu 25.10.

Here is how it looks like:
ubuntu@special06:~$ sudo multipath -ll
[sudo: authenticate] Password:
mpatha (3600507630bffd3d70000000000000005) dm-0 IBM,2107900
size=96G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
`-+- policy='service-time 0' prio=50 status=active
  |- 0:0:0:1074085888 sda 8:0 active ready running
  |- 0:0:1:1074085888 sdb 8:16 active ready running
  |- 1:0:0:1074085888 sdc 8:32 active ready running
  `- 1:0:1:1074085888 sdd 8:48 active ready running
mpathb (3600507630bffd3d70000000000000107) dm-4 IBM,2107900
size=96G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
`-+- policy='service-time 0' prio=50 status=active
  |- 3:0:0:1074216961 sdg 8:96 active ready running
  |- 3:0:1:1074216961 sdh 8:112 active ready running
  |- 2:0:0:1074216961 sde 8:64 active ready running
  `- 2:0:1:1074216961 sdf 8:80 active ready running
ubuntu@special06:~$ sudo dmsetup ls --tree
mpatha-part1 (252:1)
 └─mpatha (252:0)
    ├─ (8:48)
    ├─ (8:32)
    ├─ (8:16)
    └─ (8:0)
mpathb (252:4)
 ├─ (8:80)
 ├─ (8:64)
 ├─ (8:112)
 └─ (8:96)
ubuntu--vg-ubuntu--lv (252:3)
 └─mpatha-part2 (252:2)
    └─mpatha (252:0)
       ├─ (8:48)
       ├─ (8:32)
       ├─ (8:16)
       └─ (8:0)

Maybe your multipath setup is a bit different (I have 4 HBAs, two per LUN, you may have just 2 HBAs that server both of your two LUNs), and you may have installed the OS across your two LUNS ? (I Haven, for two LUNs are attached to the system, but the install was only on a single one).

So could you please share more details about your multipath setup and disk layout (to be able to recreate more exactyl on my side?)

[Frank Heimes (fheimes)]

In the past we had once issues with installing on SCSI LUNs that already have data on it from a previous installation (the probert component of the installer was not always able to properly read/interpret that data).
Due to this I just did a reinstall on the same system with the two LUNs, now that they are no longer clean and have some data on it, and the installation succeeded again.

So if you could share more details on how your particular system is setup, multipath, # of HBAs, amount of LUNS (2 or more), installation distributed across the LUNs, or only installed on one, etc. - that could be helpful for another recreation attempt.

[Frank Heimes (fheimes)]

It would also be interesting to know if you are using the SCSI LUNs with LVM on top or without.