[Bug 2080474] Comment bridged from LTC Bugzilla

[bugproxy]

------- Comment From vajain21 at in.ibm.com 2025-06-07 16:08 EDT-------
Found a possible fix for this bug
===========================

I tried adding multipath module to the installer initrd via initramfs-
tools. This had the effect of initializing multipath during early initrd
and before dm-multipath and lvm were initialized. With this change (
also a possible bug fix in initramfs-tools described below ) the dm-
multipath disks were properly probed and recognized by probert.

Possible issue with initramfs-tools
===============================

I see initramfs-tools ( to be more accurate ubuntu's multipath-tools package) only add two scripts:
* init-top to invoke multipathd
* local-bottom to kill the instance of multipathd

However since local-bottom script will only be invoked if initrd is
directly booting from a multipath disk hence its never invoked during
installation and running instance of multipathd is never killed. This
has an unfortunate side effect of  interfering with curtin's multipathd
service which fails due to an existing instance of multipathd running.

Fixing the possible issue with initramfs-tools and multipath-tools
========================================================
To fix this, I copied the local-bottom copy of multipath script to  'init-bottom' which would be invoked before curtin's init is invoked. This change ensured that early-init instance of multipathd will be terminated and new instance of multipath.service from curtin comes up fine.

Changes suggested
================
* Add multipath module to installer initrd via initramfs-tools. So that multipath volumes are initialized before lvm is initialized.
* Update multipath-tools to also add a init-bottom script to initramfs-tool scripts so that early-initrd instance of multipathd is terminated before curtin's multipathd daemon is invoked.

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https://bugs.launchpad.net/bugs/2080474

Title:
  ubuntu installation failing for systems having SAN disk

Status in subiquity:
  New
Status in The Ubuntu-power-systems project:
  Incomplete
Status in multipath-tools package in Ubuntu:
  New
Status in subiquity package in Ubuntu:
  New

Bug description:
  == Comment: - Anushree Mathur ==
  OS: 24.04 LTS (Noble Numbat)
  I started the Ubuntu installation for 24.04 LTS (Noble Numbat) on L1(HOST) having SAN disk, it failed with the following error just after I chose the disk.

  Ubuntu 24.04 LTS ubuntu-server hvc0

  
  connecting...  
  waiting for cloud-init...  
  generating crash report
  report saved to /var/crash/1724388235.797082424.ui.crash
  Traceback (most recent call last):
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/client/controllers/filesystem.py", line 273, in _guided_choice
      self.ui.set_body(FilesystemView(self.model, self))
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 485, in __init__
      self.refresh_model_inputs()
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/ui/views/filesystem/filesystem.py", line 540, in refresh_model_inputs
      self.avail_list.refresh_model_inputs()
    File "/snap/subiquity/5745/lib/python3.10/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/5745/lib/python3.10/site-packages/subiquity/ui/views/filesystem/helpers.py", line 32, in summarize_device
      anns = labels.annotations(device) + labels.usage_labels(device)
    File "/snap/subiquity/5745/usr/lib/python3.10/functools.py", line 889, in wrapper
      return dispatch(args[0].__class__)(*args, **kw)
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/common/filesystem/labels.py", line 100, 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/5745/usr/bin/subiquity", line 8, in <module>
      sys.exit(main())
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/cmd/tui.py", line 158, in main
      asyncio.run(run_with_loop())
    File "/snap/subiquity/5745/usr/lib/python3.10/asyncio/runners.py", line 44, in run
      return loop.run_until_complete(main)
    File "/snap/subiquity/5745/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
      return future.result()
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/cmd/tui.py", line 156, in run_with_loop
      await subiquity_interface.run()
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquity/client/client.py", line 403, in run
      await super().run()
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquitycore/tui.py", line 351, in run
      await super().run()
    File "/snap/subiquity/5745/lib/python3.10/site-packages/subiquitycore/core.py", line 134, in run
      raise exc
  RuntimeError: coroutine raised StopIteration

  Ubuntu 24.04 LTS ubuntu-server hvc0

  
  connecting...  
  ProblemType: Bug
  Architecture: ppc64el
  CrashDB: {'impl': 'launchpad', 'project': 'subiquity'}

  I tried following 2 installation methods, it is failing in both the ways: 
  1) kexec method
  2) attaching vdvd and starting installer

  NOTE: It is happening only when the system has SAN disks otherwise this installation worked fine.
  I will be attaching the crash report for this!

  == Comment:- Hariharan T S ==
  Verified the following cases. 
  Installation on Disk from VIOS  - PASSED
  Installatoin on Disk from VIOS and system had Disks from SAN - FAILED
  Installation on Disk from SAN and system ahd Disk from VIOS - FAILED

  == Comment:- Vaibhav Jain ==
  Problem seems to happening when Subuquity enters the disk partition view. The system has a SAN disk and an existing Mullti Path DM volume on it.

  Mirroring to distro

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