[Bug 2080474] Re: ubuntu installation failing for systems having SAN disk

[Olivier Gayot]

I did further analysis on amd64 + qemu today.

I figured that the EBUSY error is caused by LVM creating a DM entry
(e.g. ubuntu--vg-ubuntu--lvm on a typical install) using paths such as
/dev/sda and /dev/sdb - before multipathd has a chance to start and
create the /dev/mapper/mpatha device.

After boot:

$ multipath -ll
$ pvs
  WARNING: Not using device /dev/sdb3 for PV [...]
  WARNING: PV [...] prefers device /dev/sda3 because device is used by LVM.
  PV         VG        Fmt  Attr PSize  PFree
  /dev/sda3  ubuntu-vg lvm2 a--  <6.25g    0
$ journalctl -u multipathd
ubuntu-server multipathd[941]: mpatha: addmap [0 16777216 multipath 0 0 2 1 service-time 0 1 1 8:0 1 service-time 0 1 1 8:16 1]
ubuntu-server multipathd[941]: libdevmapper: ioctl/libdm-iface.c(1990): device-mapper: reload ioctl on mpatha (252:1) failed: Device or resource busy
ubuntu-server multipathd[941]: dm_addmap: libdm task=0 error: Device or resource busy
ubuntu-server multipathd[941]: mpatha: ignoring map
$ ls /dev/mapper/
control ubuntu--vg-ubuntu--lv

At this point restarting multipathd does not help - it still fails with
EBUSY.

However, after removing the /dev/mapper entry created by LVM and
restarting multipathd, the situation becomes as expected, and the
installation can proceed.

$ dmsetup remove /dev/mapper/ubuntu--vg-ubuntu--lv
$ systemctl restart multipathd
$ multipath -ll
mpatha (0QEMU_QEMU_HARDDISK_MPIO) dm-0 QEMU,QEMU HARDDISK
size=8.0G features='0' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=1 status=active
| `- 0:0:0:0 sda 8:0  active ready running
`-+- policy='service-time 0' prio=1 status=enabled
  `- 0:0:1:0 sdb 8:16 active ready running
$ ls /dev/mapper
control  mpatha  mpatha-part1  mpatha-part2  mpatha-part3  ubuntu--vg-ubuntu--lv
$ pvs
  PV                       VG        Fmt  Attr PSize  PFree
  /dev/mapper/mpatha-part3 ubuntu-vg lvm2 a--  <6.25g    0


I wonder if we should make multipathd run before LVM? And is it going to address the issue originally reported - or only what we were able to reproduce using qemu on amd64.

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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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