Fresh Bionic install hangs forever at 66% waiting for os-prober

[Evan Hoffman]

Installing Ubuntu 18.04 cleanly on boxes that have 14.04, the installer hangs at the end during "update grub" at 66%, forever, until I switch to another console and kill the pid of "dmsetup". Issue is described in more detail here: https://jrs-s.net/2019/05/31/ubuntu-18-04-hung-at-update-grub-66/ . I am doing a netboot preseed install using the 4.15.0-62 kernel and initrd from October 2019. When provisioning ~15 boxes at a time, 90% - 100% of them are afflicted by this. If I power cycle them and PXE them into the installer again when hung they usually run to completion.

[Chris Guiver (guiverc)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1854839

Please execute this on one box that had this issue. It'll provide some hardware details and hopefully some clues as to the issue.

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Evan Hoffman (ehoffman24)]

I may have found a workaround/fix for this. I noticed that /etc/grub.d/30-os_prober has a GRUB_DISABLE_OS_PROBER variable that will skip probing for other OSes on the machine, so I added GRUB_DISABLE_OS_PROBER=true to the kernel options and the installer proceeded to completion on a machine that was consistently hanging at 66%/osprober. I'm using foreman for the provisioning so my pxegrub2 template looks like this now:

menuentry '<%= template_name %>_uefi' {
  linuxefi <%= @kernel %> auto=true netcfg/choose_interface=<%= @host.primary_interface.identifier %>np0 url=<%= foreman_url('provision')%> ramdisk_size=10800 root=/dev/rd/0 rw auto hostname=<%= @host.name %> GRUB_DISABLE_OS_PROBER=true <%= options %>
  initrdefi <%= @initrd %>
}

As soon as I added this option, the install completed. Have only tested it on this single box, will update again if this doesn't fix it on future machines.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dimitri John Ledkov (xnox)]

also, you probably want to wipe your drive clean prior to install. This will most likely help os-prober to not hang.

Also one can preseed that to do as an early action (like in pre-partman command)