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Thread: Xen kernel not loading via Grub

  1. #1
    Join Date
    Nov 2010
    Beans
    5

    Xen kernel not loading via Grub

    Greetings Gurus!

    I've loaded a machine with 10.10 server amd64 installing only the core system and OpenSSH server. I've been following the instructions at https://help.ubuntu.com/community/Xe...Ubuntu%2010.10) which appear to be pretty new and had some hiccups with the make world which was resolved by installing additional modules and changing one of the git lines regarding local or remote branches. So the make world and sudo make install steps appear to run successfully and now I need to change grub to boot the Xen kernel.

    The instructions say to add the following to 40_custom (with my fs-uuid) and sudo update-grub:

    menuentry "Xen 4.0 2.6.32.25 pvops" {
    insmod part_msdos
    insmod ext2
    set root=(hd0,msdos1)
    search --no-floppy --fs-uuid --set 294e6dee-238e-42c2-814f-fb47aaa45571
    multiboot /boot/xen.gz
    module /boot/vmlinuz-2.6.32.25 root=/dev/sda1
    module /boot/initrd-2.6.32.25.img
    }

    Right out of the gate, I worry about the success of the menuentry due to the fact that the module lines refer to files that don't exist. Here's my /boot directory:

    sawozny@xen-host:/boot$ ls -la
    total 37150
    drwxr-xr-x 4 root root 1024 2010-12-11 12:12 .
    drwxr-xr-x 22 root root 4096 2010-12-11 10:58 ..
    -rw-r--r-- 1 root root 700570 2010-10-16 21:11 abi-2.6.35-22-server
    -rw-r--r-- 1 root root 69063 2010-12-11 14:33 config-2.6.32.26
    -rw-r--r-- 1 root root 122712 2010-10-16 21:11 config-2.6.35-22-server
    drwxr-xr-x 3 root root 4096 2010-12-11 14:37 grub
    -rw-r--r-- 1 root root 11746215 2010-12-11 10:26 initrd.img-2.6.35-22-server
    drwxr-xr-x 2 root root 12288 2010-12-11 09:13 lost+found
    -rw-r--r-- 1 root root 165084 2010-09-24 14:16 memtest86+.bin
    -rw-r--r-- 1 root root 167264 2010-09-24 14:16 memtest86+_multiboot.bin
    -rw-r--r-- 1 root root 2375083 2010-12-11 14:33 System.map-2.6.32.26
    -rw-r--r-- 1 root root 2365429 2010-10-16 21:11 System.map-2.6.35-22-server
    -rw-r--r-- 1 root root 1335 2010-10-16 21:14 vmcoreinfo-2.6.35-22-server
    -rw-r--r-- 1 root root 4684000 2010-12-11 14:33 vmlinuz-2.6.32.26
    -rw-r--r-- 1 root root 4388496 2010-10-16 21:11 vmlinuz-2.6.35-22-server
    -rw-r--r-- 1 root root 679132 2010-12-11 11:28 xen-4.0.1.gz
    lrwxrwxrwx 1 root root 12 2010-12-11 12:11 xen-4.0.gz -> xen-4.0.1.gz
    lrwxrwxrwx 1 root root 12 2010-12-11 12:11 xen-4.gz -> xen-4.0.1.gz
    lrwxrwxrwx 1 root root 12 2010-12-11 12:11 xen.gz -> xen-4.0.1.gz
    -rw-r--r-- 1 root root 10388082 2010-12-11 11:28 xen-syms-4.0.1
    sawozny@xen-host:/boot$

    I get 10 new boot entries right after my original default entries that result in either an error or a reboot. Here they are:

    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN syms-4.0.1
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN syms-4.0.1 (recovery mode)
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN 4
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN 4 (recovery mode)
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN 4.0
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN 4.0 (recovery mode)
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN 4.0.1
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN 4.0.1 (recovery mode)
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN xen
    - Ubuntu, GNU/Linux, with 2.6.32.26 and XEN xen (recovery mode)

    I'm assuming these arrived because of the new files and symlinks update-grub found in my /boot directory. The update-grub ALSO doesn't run cleanly which is probably part of why these non-functional grub entries exist.

    Here are the results of the update-grub with the errors that make me nervous:

    sawozny@xen-host:~$ sudo update-grub
    [sudo] password for sawozny:
    Generating grub.cfg ...
    Found linux image: /boot/vmlinuz-2.6.35-22-server
    Found initrd image: /boot/initrd.img-2.6.35-22-server
    Found linux image: /boot/vmlinuz-2.6.32.26
    dpkg: version '/boot/xen.gz' has bad syntax: invalid character in version number
    Found linux image: /boot/vmlinuz-2.6.32.26
    dpkg: version '/boot/xen.gz' has bad syntax: invalid character in version number
    Found linux image: /boot/vmlinuz-2.6.32.26
    dpkg: version '/boot/xen.gz' has bad syntax: invalid character in version number
    Found linux image: /boot/vmlinuz-2.6.32.26
    dpkg: version '/boot/xen.gz' has bad syntax: invalid character in version number
    Found linux image: /boot/vmlinuz-2.6.32.26
    Found linux image: /boot/vmlinuz-2.6.32.26
    Found memtest86+ image: /memtest86+.bin
    done
    sawozny@xen-host:~$

    So, I decided to press on with the instructions and install EXT4 support with the following commands:

    - make linux-2.6-pvops-config CONFIGMODE=menuconfig #where I went into the menus and added any EXT4 module I could find
    - make linux-2.6-pvops-build
    - sudo make linux-2.6-pvops-install

    Then I ran another sudo update-grub and rebooted, trying the custom menu entry. When I do, this is what I get:

    - error: couldn't open file.
    - error: you need to load the multiboot kernel first (this line appears twice)

    Back to my earlier point, I tried to modify the lines added to 40_custom to match files that actually exist in my boot directory, but after another sudo update-grub, the error message on boot is the same.

    If anyone has any idea what's gone wrong here, I'd appreciate any assistance you can offer. I don't mind doing the research, but I can't find a good resource on modifying grub to boot Xen kernels. If anyone knows of any, I'd appreciate being pointed in the right direction. These instructions, as published in the Ubuntu community documentation, are pretty new so Google hasn't been much of a help.

    Thanks in advance for any and all suggestions,

    Scott

  2. #2
    Join Date
    Aug 2010
    Beans
    2

    Re: Xen kernel not loading via Grub

    Hi Scott,

    since monday I'm trying to instal xen on ubuntu 10.10 either.
    I've the kernel up and running, but without X up to now.

    Regarding your problem:
    are you sure that you have set all parameters in etc/grub.d appropriate?
    note that you have to set the initrd to an existing one, as it is not build within the makefiles. maybe that's the problem.
    here are my settings, if you want, I can post you the grub.cfg part as well.

    Code:
    menuentry "Xen 4.0  2.6.32.26 pvops" {
    insmod part_msdos
    insmod ext2
    set root=(hd0,msdos1)
    search --no-floppy --fs-uuid --set 3eb65281-f30f-42c3-90c1-6bd9c98b01c0
    multiboot /boot/xen.gz
    module /boot/vmlinuz-2.6.32.26 root=/dev/sda1
    module /boot/initrd.img-2.6.32-26-generic-pae
    }
    when running update-grub I get the same errors, don't look like a big issue as my kernel is booting.

    hope that helps.

  3. #3
    Join Date
    Mar 2013
    Beans
    1

    Re: Xen kernel not loading via Grub

    Hi there,

    I'm in trouble with an issue that looks like yours, namely : I have an "error : couldn't open file" error message when lauchning Xen 4.1-amd64 from grub.

    First of all, this is my configuration :
    Ubuntun 12.10, installed in windows 7


    Here is my issues :
    I followed, of course, a number of tutorials, and came to the following point a installing Xen


    I have the xen-4.1-amd64.gz archive in /boot


    Here is what I have in /boot/grub/grub.cfg :


    ### BEGIN /etc/grub.d/20_linux_xen ###
    submenu "Xen 4.1-amd64" {
    menuentry 'Ubuntu GNU/Linux, avec Xen 4.1-amd64 et Linux 3.2.0-23-generic' --class ubuntu --class gnu-linux --class gnu --class os --class xen {
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos3)'
    search --no-floppy --fs-uuid --set=root F282A3B682A37DAB
    echo 'Chargement de Xen 4.1-amd64 ...'
    multiboot /boot/xen-4.1-amd64.gz placeholder
    echo 'Chargement de Linux 3.2.0-23-generic ...'
    module /boot/vmlinuz-3.2.0-39-generic placeholder root=/dev/mapper/control ro
    echo 'Chargement du disque mémoire initial ...'
    module /boot/initrd.img-3.2.0-39-generic
    }
    menuentry 'Ubuntu GNU/Linux, avec Xen 4.1-amd64 et Linux 3.2.0-23-generic (mode de dépannage)' --class ubuntu --class gnu-linux --class gnu --class os --class xen {
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos3)'
    search --no-floppy --fs-uuid --set=root F282A3B682A37DAB
    echo 'Chargement de Xen 4.1-amd64 ...'
    multiboot /boot/xen-4.1-amd64.gz placeholder
    echo 'Chargement de Linux 3.2.0-23-generic ...'
    module /boot/vmlinuz-3.2.0-39-generic placeholder root=/dev/mapper/control ro single
    echo 'Chargement du disque mémoire initial ...'
    module /boot/initrd.img-3.2.0-39-generic
    }
    }
    ### END /etc/grub.d/20_linux_xen ###



    And so, when grub starts, I choose "Xen 4.1-amd64",
    then
    "Ubuntu GNU/Linux, avec Xen 4.1-amd64 et Linux 3.2.0-23-generic"


    after which I got these 3 beautiful messages :
    Xen 4.1-amd64
    error : couldn't open file
    Linux-generic...
    you need to load the multiboot kernel first
    Mem init...
    you need to load the multiboot kernel first


    I guess the 2 last messages are a consequence of the first, but I can't figure why grub couldn't open Xen 4.1-amd64, that is to say /boot/xen-4.1-amd64.gz


    I'd be hugely thankful if someone could help me in any way ! Thanks in advance !

  4. #4
    Join Date
    Feb 2007
    Location
    West Hills CA
    Beans
    9,280
    Distro
    Ubuntu 14.04 Trusty Tahr

    Re: Xen kernel not loading via Grub

    So, if I understand your issue, you are trying to launch a virtualized environment inside a virtualized environment? What virtual machine is running Ubuntu 12.10 inside Windows7? Does that virtual machine allow a virtual machine OS as a guest?

    How about taking bare hardware--with no other operating system, and loading Xen?

    This is an old thread (2010) and is likely to be closed.
    -------------------------------------
    Oooh Shiny: PopularPages

    Unumquodque potest reparantur. Patientia sit virtus.

  5. #5
    Join Date
    Feb 2008
    Location
    Texas
    Beans
    15,671
    Distro
    Ubuntu 14.04 Trusty Tahr

    Re: Xen kernel not loading via Grub

    If a post is older than a year or so and hasn't had a new reply in that time, instead of replying to it, create a new thread. In the software world, a lot can change in a very short time, and doing things this way makes it more likely that you will find the best information. You may link to the original discussion in the new thread if you think it may be helpful.

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