Arch Linux

cafce25

Member

Registered: 2021-03-21

Posts: 1

Timed out waiting for device /dev/.<truncated-uuid> under Hyper-V

tl;dr I've got an arch installation that doesn't mount under Hyper-V with strange references to sorta /dev/by-uuid like paths.

During the holidays I've been messing with a maybe somewhat contrived way to install arch: Instead of creating a bootable media (because I don't have an usb stick with me) I connected my new SSD directly to a Hyper-V VM with another linux (alma linux though I doubt it's relevant). I partitioned the disk and then copied the current bootstrap image (archlinux-bootstrap-x86_64.tar.zst) to the root. I subsequently arch-chrooted into that partition, installed a kernel, bootloader (grub) and other essentials.

Since I wanted to experiment enabling secure boot I installed the signed PreLoader (and HashTool) from AUR and made grub a standalone efi executable with the config embedded.

When I had everything in what I thought to be working order (yeah actually a couple of boot check, dang forgot XYZ, re-chroot install missing bit cycles in between) I attached the drive to a fresh VM with only that disk attached and tried to boot it which… didn't work:

[ TIME ] Timed out waiting for device /dev/.352628-ff99-4697-be0e-4720ac3880a9.
[DEPEND] Dependency failed for Cryptography Setup for root.
[DEPEND] Dependency failed for Local Encrypted Volumes.
[ TIME ] Timed out waiting for device /dev/.0689be-11cf-4fd2-9033-b470078b2796.
[DEPEND] Dependency failed for /sysroot.
[DEPEND] Dependency failed for Initrd Root File System.
[DEPEND] Dependency failed for Mountpoints Configured in the Real Root.
[DEPEND] Dependency failed for Initrd Root Device.
[DEPEND] Dependency failed for File System .0689be-11cf-4fd2-9033-b470078b2796.
You are in emergency mode. After logging in, type "journalctl -xb" to view
system logs, "systemctl reboot" to reboot, or "exit"
to continue bootup.

Cannot open access to console, the root account is locked.
See sulogin(8) man page for more details.

Press Enter to continue.

Now the thing is those missing device paths look eerily similar to the actual UUIDs in use here:

# /etc/crypttab.initramfs

root UUID=33352628-ff99-4697-be0e-4720ac3880a9 none timeout=90

# /etc/fstab

# /dev/mapper/root
UUID=480689be-11cf-4fd2-9033-b470078b2796       /               btrfs           rw,relatime,ssd,space_cache=v2,subvol=/root/arch        0 0

# /dev/sdb1
UUID=D4DD-FEE9          /boot           vfat            rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro        0 2

As you can see the missing devices are truncated versions of the encrypted and unencrypted root partition respectively but instead of an expected /dev/by-uuid/33352628-ff99-4697-be0e-4720ac3880a9 or /dev/by-uuid/480689be-11cf-4fd2-9033-b470078b2796 somehow the by-uuid/xx part got replaced by a single dot.

I kept messing with this setup in the VM a bit but couldn't find anything but no dice.

In a last ditch effort I just tried booting the disk on the bare system and to my surprise it just worked… Even the secure boot bart which I expected to cause me some headaches just worked.
This is the point where I'm at a loss. The configuration seems to be ok since the bare metal is able to boot it. But Hyper-V is able to boot different bootable media or installations just fine so that doesn't seem to be it either.
But something in the combination of my frankenstein arch with Hyper-V seems to hiccup and thus it fails to find my drive.

Has anyone encountered something like this or otherwise a clue if/how I can boot from that drive under Hyper-V?