** Description changed: [ Impact ] When booting an affected Ubuntu Server installer ISO on a system where a multipath device is used as a LVM PV, installing Ubuntu is not possible. Such a situation happens when a previous *LVM* installation of any OS (i.e., not necessarily Ubuntu) was done on a multipath disk, present on the system. The symptoms typically include: * a crash of the Subiquity client * the following error in the journal: ``` 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 ``` * the VG device mapper node exists (e.g., ubuntu-vg) but the multipath one does not (e.g., mpatha) Explanation ----------- Although LVM support is included in the initramfs of the installer ISO, multipath support is not. As a result, during the transition out of the initramfs, LVM VGs are activated using an individual underlying path device instead of the consolidated multipath device mapper node. Example ------- Let's assume /dev/sda and /dev/sdb refer to the same disk via different paths. It is intended that sda and sdb are consolidated under a multipath device node, which in turn should be used as a PV. Excepted result in the live environment --------------------------------------- /dev/sda --> consolidated under mpatha /dev/sdb --> consolidated under mpatha /dev/mapper/mpatha --> used as the PV of ubuntu-vg /dev/mapper/ubuntu-vg --> the VG that uses mpatha as the PV Actual result on affected ISO ----------------------------- /dev/sda --+ /dev/sdb ----> one of these is used as the PV for ubuntu-vg /dev/mapper/mpatha <-- does not exist /dev/mapper/ubuntu-vg (uses /dev/sda or /dev/sdb as the PV) [ Proposed fix ] * Since 25.10, we added support to multipath in the initramfs of the Ubuntu Server ISOs. I propose doing the same for 24.04.5. * This would correspond to: - * a livecd-rootfs upload, ensuring multipath-tools-boot is installed when building the installer's initramfs. - * a multipath-tools upload to fix: - * a bug making the multipathd process linger when executed in the installer environment. - * a bug making multipathd refuse to start if no bindings file is present (i.e., bug 2120444) + * a livecd-rootfs upload, ensuring multipath-tools-boot is installed when building the installer's initramfs. + * a multipath-tools upload to fix: + * a bug making the multipathd process linger when executed in casper's initramfs (because we use nfs-* scripts and not local-* scripts) + * a bug making multipathd refuse to start if no bindings file is present (i.e., bug 2120444) [ Test Plan ] - TODO + 1. Get an Ubuntu Server ISO built using livecd-rootfs and multipath-tools-boot + 2. Ensure the ISO includes multipath support: + # mkdir /tmp/test-initramfs + # unmkinitramfs /mnt/loop/casper/initrd /tmp/test-initramfs/ + # find -name multipathd + ./usr/sbin/multipathd + + 3. Get a test-bed ready by install an OS (for instance Ubuntu Server 26.04) using multipath + LVM. + $ kvm-test --install --iso /srv/iso/ubuntu-26.04-live-server-amd64.iso --disk-interface scsi-multipath --recreate-target + + 4. (optional). Boot the 24.04.4 server ISO and experience the issue: + $ kvm-test --install --iso /srv/iso/ubuntu-24.04.4-live-server.amd64.iso -- disk-interface scsi-multipath --reuse-target + + 5. Boot the fixed ISO and ensure the installation can proceed to the + end. + + $ kvm-test --install --iso /srv/iso/ubuntu-24.04.4-live- + server.amd64.iso -- disk-interface scsi-multipath --reuse-target + + The kvm-test script can be found here at + https://github.com/canonical/subiquity/blob/main/scripts/kvm-test.py or + in ppa:ogayot/subiquity [ Where problems could occur? ] * Bringing multipath support in the installer's initramfs could slightly slow down the boot process of the ISO. Nevertheless, 25.10 and 26.04 Ubuntu Server ISOs have had multipath-support in the initramfs, and no measurable slow down has been experienced. The change is affecting ubuntu-server only. - * The multipath-tools fix is a bit more involved. It affects all systems, not just ISOs. + * The multipath-tools fixes are a bit more involved. They can in theory affect all systems using multipath, not just installer ISOs. That said, the number of setups that use both multipath and nfs-* scripts should be very low. Most setups use local-* scripts instead - with the exception of casper's initramfs that we have in installer ISOs. [ Other Info ] * For existing affected ISOs, there is a workaround but not a user-friendly one: 1. open a shell in the installer environment (one can hit F2 in the Subiquity TUI) 2. Delete the relevant VG using `dmsetup remove`: $ sudo dmremove /dev/mapper/<vg> 3. Restart multipathd using: $ sudo systemctl restart multipathd 4. Finally, restart Subiquity: $ sudo snap restart subiquity * Alternatively, users can wipe the affected disk and then restart he installer (but this involves manually erasing data from the disk). [ Original 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
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2080474 Title: [SRU] cannot install Ubuntu Server over a multipath disk used as an LVM PV To manage notifications about this bug go to: https://bugs.launchpad.net/subiquity/+bug/2080474/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
