Bootable buildd xenial images go to initramfs on boot

[Michał Sawicz]

This image:

http://cloud-images.ubuntu.com/daily/server/buildd/daily/xenial/current/xenial-server-cloudimg-amd64-disk.img

Fails to boot, with either UEFI or MBR:

```
error: can't find command `hwmatch'.
error: no such device: root.
```

Then it goes straight into initramfs.

Every once in a while there's more context written:

```
mount: can't find /root in /etc/fstab
mount: mounting /dev on /root/dev failed: No such file or directory
mount: mounting /run on /root/run failed: No such file or directory
run-init: current directory on the same filesystem as the root: error 0
Target filesstem doesn't have requested /sbin/init.
run-init: current directory on the same filesystem as the root: error 0
...
No init found. Try passing init= bootarg.
```

[Joshua Powers (powersj)]

Per LP: #1915571 as soon as I set console=ttyS0 in the kernel cmdline, the image is able to boot in qemu with output to the console. As such, I think this is really a duplicate of bug LP: #1915571.

To test this out I downloaded the image, modified /boot/grub/grub.cfg to remove quiet and add "console=ttyS0", and then booted the image with:

qemu-system-x86_64 \
  -cpu host -machine type=q35,accel=kvm -m 2048 \
  -nographic \
  -snapshot \
  -netdev id=net00,type=user,hostfwd=tcp::2222-:22 \
  -device virtio-net-pci,netdev=net00 \
  -drive if=virtio,format=qcow2,file=xenial-server-cloudimg-amd64-disk.img \
  -drive if=virtio,format=raw,file=seed.img

Prior to this change, I did not get any output to the console and it appeared like the image was not booting.

I'll mark this as incomplete for now. Thoughts?

[Michał Sawicz (saviq)]

Hey, making the ttyS0 change did enable the serial console, of course, but I'm still dropped into initramfs on ttyS0, whether importing the image into virt-manager or using your line (without seed.img).

My qemu line:

qemu-system-x86_64 \
  -cpu host -machine type=q35,accel=kvm -m 2048 \
  -snapshot \
  -netdev id=net00,type=user,hostfwd=tcp::22222-:22 \
  -device virtio-net-pci,netdev=net00 \
  -drive if=virtio,format=qcow2,file=xenial-test.qcow2

And after Ctrl+Alt+3:

Begin: Will now check file system ... fsck from util-linux 2.27.1
Checking all file systems.
done.
mount: can't find /root in /etc/fstab
done.
Begin: Running /scripts/local-bottom ... done.
Begin: Running /scripts/init-bottom ... mount: mounting /dev on /root/dev failed: No such file or directory
done.
mount: mounting /run on /root/run failed: No such file or directory
run-init: current directory on the same filesystem as the root: error 0
Target filesystem doesn't have requested /sbin/init.
run-init: current directory on the same filesystem as the root: error 0
run-init: current directory on the same filesystem as the root: error 0
run-init: current directory on the same filesystem as the root: error 0
run-init: current directory on the same filesystem as the root: error 0
run-init: current directory on the same filesystem as the root: error 0
No init found. Try passing init= bootarg.

BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs)

[Joshua Powers (powersj)]

Marking confirmed

# Steps to reproduce

1. wget http://cloud-images.ubuntu.com/daily/server/buildd/daily/xenial/current/xenial-server-cloudimg-amd64-disk.img
2. Modify /etc/boot/grub.cfg to add "console=ttyS0" to kernel command line
3. Boot using the following qemu CLI:

qemu-system-x86_64 \
  -cpu host -machine type=q35,accel=kvm -m 2048 \
  -snapshot \
  -nographic \
  -netdev id=net00,type=user,hostfwd=tcp::22222-:22 \
  -device virtio-net-pci,netdev=net00 \
  -drive if=virtio,format=qcow2,file=xenial-server-cloudimg-amd64-disk.img

# Expected behavior

Boot to login

# Actual behavior

Boot drops to an initramfs busy box console

[Gauthier Jolly (gjolly)]

Hi,

Checking the cmdline, the root filesystem is not set:

/boot/vmlinuz-4.4.0-21-generic root= ro quiet splash $vt_handoff

If I change it to "root=PARTUUID=fb561bdb-b68a-44ae-a884-a5fd70f80cf7" it's booting.

I see also two other errors during boot:

[ 0.075065] core perfctr but no constraints; unknown hardware!
fsck: error 2 (No such file or directory) while executing fsck.ext4 for /dev/vda1
fsck exited with status code 8

The fsk issue is also present in the bionic images I tried but not the perfctr one.

I just think something went/was wrong when grub was updated during build.