Boot problem with Xen DomU after kernel upgrade

[Mathias Weidner]

Setting:

- Xen Dom0 running Ubuntu Server 12.04
- Xen DomU running Ubuntu Server 12.04

$ lsb_release -rd
Description: Ubuntu 12.04.1 LTS
Release: 12.04

$ apt-cache policy grub2-common
grub2-common:
  Installed: 1.99-21ubuntu3.4
  Candidate: 1.99-21ubuntu3.4
  Version table:
 *** 1.99-21ubuntu3.4 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1.99-21ubuntu3 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

$ apt-cache policy xen-utils-4.1
xen-utils-4.1:
  Installiert: 4.1.2-2ubuntu2.4
  Kandidat: 4.1.2-2ubuntu2.4
  Versionstabelle:
 *** 4.1.2-2ubuntu2.4 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise-updates/universe amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ precise-security/universe amd64 Packages
        100 /var/lib/dpkg/status
     4.1.2-2ubuntu2 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages

DomU was installed with Netboot-Image on a LVM volume. Bootloader than changed to pygrub.

--- Xen configuration for machine ---
name = "openldaptest"
memory = 256
disk = ['phy:/dev/camion/openldaptest,xvda,w']
vif = ['bridge=xenbr0']
bootloader = "pygrub"
---

Did `apt-get dist-upgrade` inside the DomU with kernel upgrade and after `init 6` the DomU would not boot anymore.

Starting pygrub manually:

    $ sudo /usr/bin/pygrub -n /dev/camion/openldaptest
    Using <class 'grub.GrubConf.Grub2ConfigFile'> to parse
    /boot/grub/grub.cfg
    WARNING:root:Unknown directive load_video
    WARNING:root:Unknown directive terminal_output
    WARNING:root:Unknown directive else
    WARNING:root:Unknown directive else
    WARNING:root:Unknown directive else
    WARNING:root:Unknown directive else
    WARNING:root:Unknown directive else
    WARNING:root:Unknown directive export
    WARNING:root:Unknown image directive recordfail
    WARNING:root:Unknown image directive gfxmode
    WARNING:root:Unknown image directive recordfail
    WARNING:root:Unknown directive submenu
    WARNING:root:Unknown image directive recordfail
    WARNING:root:Unknown image directive gfxmode
    WARNING:root:Unknown image directive recordfail
    Traceback (most recent call last):
      File "/usr/bin/pygrub", line 763, in <module>
        raise RuntimeError, "Unable to find partition containing kernel"
    RuntimeError: Unable to find partition containing kernel

The message 'Unknown directive submenu' was the first different from a working DomU.

So I mounted the the system partition, copied a backup over /boot/grub/grub.cfg and manually changed it to the version of the new kernel on all occurences of the version number. After that I unmounted the system partition and could start the DomU again. I then did login on the DomU and removed the old kernel with `apt-get purge`. This time after `init 6` the DomU booted fine.

So after all it is working but the process of upgrading the kernel is suboptimal.

[Launchpad Janitor (janitor)]

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

[Olli (patteh)]

On my system I found an unmatched curly bracket in /boot/grub/grub.cfg after the end of the last menuentry of this submenu for older kernels:

menuentry 'Ubuntu, with Linux 3.2.0-36-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
        [ ...SNIP...]
        initrd /boot/initrd.img-3.2.0-36-generic
}
} <------ BAD BOY
### END /etc/grub.d/10_linux ###

I uncommented "BAD BOY" and everything was fine.

Olli

[Olli (patteh)]

Forget about my last comment. The bracket is correct. Just remove the submenu entry in grub.cfg an the DomU will boot again.