kvm cannot boot xen guest using lvm

This booting error is because the Xen PV guest image uses the Xen kernel, this is not compatible with anything but a host running a Xen kernel.

I did a kpartx -av virtual.img and then it created some partitions that showed up in fdisk.

I mounted it and did a chroot into it and removed the xen kernel and installed a normal kernel but Xen still shows the same kernel in Grub (only the Xen one).

This is strange but it seems like this Xen PV guest has some sort of hidden or file based virtual /boot because I can't even see the newly installed kernel.

It's obvious that Xen must have a virtual-boot partition in the form of an image for grub somewhere on the main root filesystem but I cannot find it and as usual the Xen documentation does not refer to this or makes it too hard to find.

fdisk -l VPS.img

Disk VPS.img: 0 MB, 0 bytes 255 heads, 63 sectors/track, 0 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0008c4a7 Device Boot Start End Blocks Id System VPS.img1 * 1 13 104391 83 Linux VPS.img2 14 1305 10377990 8e Linux LVM Partition 2 has different physical/logical endings: phys=(1023, 254, 63) logical=(1304, 254, 63)

I didn't notice the VPS.img1 which was created as loop0p1 with kartpx which is actually a separate boot partition. Copy your non-xen kernel to the mounted Partition #1. Edit the boot line to reflect the non-Xen kernel and initrd

*Important note

Remove the console=/dev/xvc0 from the kernel line or the kernel will not even start to boot (this should be removed permanently). Also make sure you do a kpartx -dv VPS.img before booting and deactivate any LVM partitions from it or groups.

kpartx -dv VPS.img
device-mapper: remove ioctl on loop0p2 failed: Device or resource busy
ioctl: LOOP_CLR_FD: Device or resource busy
can't del loop : /dev/loop0

vgchange -a n /dev/VolGroup00

kpartx -dv VPS.img

del devmap : loop0p2
del devmap : loop0p1
loop deleted : /dev/loop0

For some reason I'm getting a kernel panic:

switchroot: mount failed: No such file or directory

Kernel panic - not syncing: Attempted to kill init

I believe this is because the Centos initrd for the non-Xen kernel was installed using chroot and doesn't understand it needs /dev/mapper

I used the non-Xen kernel with the Xen initrd and the process gets farther but can't access the volume groups still due to it looking for non-existent modules.

I need to create a proper initrd in Centos

cd /boot/
[root@2 boot]# ls
config-2.6.18-238.el5xen        lost+found                      System.map-2.6.18-308.24.1.el5
config-2.6.18-308.24.1.el5      message                         vmlinuz-2.6.18-238.el5xen
grub                            symvers-2.6.18-238.el5xen.gz    vmlinuz-2.6.18-308.24.1.el5
initrd-2.6.18-238.el5xen.img    symvers-2.6.18-308.24.1.el5.gz xen.gz-2.6.18-238.el5
initrd-2.6.18-308.24.1.el5.img System.map-2.6.18-238.el5xen    xen-syms-2.6.18-238.el5
[root@2 boot]# mv initrd-2.6.18-308.24.1.el5.img initrd-2.6.18-308.24.1.el5.img.old
[root@2 boot]# mkinitrd initrd-2.6.18-308.24.1.el5.img 2.6.18-308.24.1.el5
error opening /sys/block: No such file or directory
error opening /sys/block: No such file or directory
No module xenblk found for kernel 2.6.18-308.24.1.el5, aborting.

before chrooting, do a mount -o bind /sys /root/mnt/sys

mkinitrd --with lvm --force-lvm-probe -v -f initrd-2.6.18-308.24.1.el5.img 2.6.18-308.24.1.el5
Creating initramfs
Looking for deps of module ehci-hcd
Looking for deps of module ohci-hcd
Looking for deps of module uhci-hcd
Looking for deps of module ext3: jbd
Looking for deps of module jbd
Looking for driver for device VolGroup00/LogVol00
Looking for driver for device VolGroup00/LogVol01
Looking for deps of module ide-disk
Looking for deps of module dm-mem-cache
Looking for deps of module dm-region_hash: dm-mod dm-log
Looking for deps of module dm-mod
Looking for deps of module dm-log: dm-mod
Looking for deps of module dm-message
Looking for deps of module dm-raid45: dm-message dm-mod dm-mem-cache dm-log dm-region_hash
Looking for deps of module lvm
No module lvm found for kernel 2.6.18-308.24.1.el5, aborting.

mkinitrd -v -f initrd-2.6.18-308.24.1.el5.img 2.6.18-308.24.1.el5Creating initramfs
Looking for deps of module ehci-hcd
Looking for deps of module ohci-hcd
Looking for deps of module uhci-hcd
Looking for deps of module ext3: jbd
Looking for deps of module jbd
Looking for driver for device VolGroup00/LogVol00
Looking for driver for device VolGroup00/LogVol01
Looking for deps of module ide-disk
Looking for deps of module dm-mem-cache
Looking for deps of module dm-region_hash: dm-mod dm-log
Looking for deps of module dm-mod
Looking for deps of module dm-log: dm-mod
Looking for deps of module dm-message
Looking for deps of module dm-raid45: dm-message dm-mod dm-mem-cache dm-log dm-region_hash
Using modules: /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ehci-hcd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ohci-hcd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/uhci-hcd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/fs/jbd/jbd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/fs/ext3/ext3.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mem-cache.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mod.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-log.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-region_hash.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-message.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-raid45.ko
/sbin/nash -> /tmp/initrd.124034/bin/nash
/sbin/insmod.static -> /tmp/initrd.124034/bin/insmod
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ehci-hcd.ko' [elf32-i386] to `/tmp/initrd.124034/lib/ehci-hcd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ohci-hcd.ko' [elf32-i386] to `/tmp/initrd.124034/lib/ohci-hcd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/uhci-hcd.ko' [elf32-i386] to `/tmp/initrd.124034/lib/uhci-hcd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/fs/jbd/jbd.ko' [elf32-i386] to `/tmp/initrd.124034/lib/jbd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/fs/ext3/ext3.ko' [elf32-i386] to `/tmp/initrd.124034/lib/ext3.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mem-cache.ko' [elf32-i386] to `/tmp/initrd.124034/lib/dm-mem-cache.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mod.ko' [elf32-i386] to `/tmp/initrd.124034/lib/dm-mod.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-log.ko' [elf32-i386] to `/tmp/initrd.124034/lib/dm-log.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-region_hash.ko' [elf32-i386] to `/tmp/initrd.124034/lib/dm-region_hash.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-message.ko' [elf32-i386] to `/tmp/initrd.124034/lib/dm-message.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-raid45.ko' [elf32-i386] to `/tmp/initrd.124034/lib/dm-raid45.ko' [elf32-i386]
/sbin/dmraid.static -> /tmp/initrd.124034/bin/dmraid
/sbin/kpartx.static -> /tmp/initrd.124034/bin/kpartx
Adding module ehci-hcd
Adding module ohci-hcd
Adding module uhci-hcd
Adding module jbd
Adding module ext3
Adding module dm-mem-cache
Adding module dm-mod
Adding module dm-log
Adding module dm-region_hash
Adding module dm-message
Adding module dm-raid45

this did it, the mnt proc and dev

mount -o bind /proc mnt/proc/
[root@12 ~]# mount -o bind /dev mnt/dev/
[root@12 ~]# chroot mnt
[root@12 /]# cd /boot/
[root@12 boot]# mkinitrd -v -f initrd-2.6.18-308.24.1.el5.img 2.6.18-308.24.1.el5
Creating initramfs
Looking for deps of module ehci-hcd
Looking for deps of module ohci-hcd
Looking for deps of module uhci-hcd
Looking for deps of module ext3: jbd
Looking for deps of module jbd
Looking for driver for device mapper/loop0p2
Found DM device mapper/loop0p2
Looking for deps of module ide-disk
Looking for deps of module dm-mod
Looking for deps of module dm-mirror: dm-mod dm-log
Looking for deps of module dm-log: dm-mod
Looking for deps of module dm-zero: dm-mod
Looking for deps of module dm-snapshot: dm-mod
Looking for deps of module dm-mem-cache
Looking for deps of module dm-region_hash: dm-mod dm-log
Looking for deps of module dm-message
Looking for deps of module dm-raid45: dm-message dm-mod dm-mem-cache dm-log dm-region_hash
Using modules: /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ehci-hcd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ohci-hcd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/uhci-hcd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/fs/jbd/jbd.ko /lib/modules/2.6.18-308.24.1.el5/kernel/fs/ext3/ext3.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mod.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-log.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mirror.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-zero.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-snapshot.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mem-cache.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-region_hash.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-message.ko /lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-raid45.ko
/sbin/nash -> /tmp/initrd.125242/bin/nash
/sbin/insmod.static -> /tmp/initrd.125242/bin/insmod
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ehci-hcd.ko' [elf32-i386] to `/tmp/initrd.125242/lib/ehci-hcd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/ohci-hcd.ko' [elf32-i386] to `/tmp/initrd.125242/lib/ohci-hcd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/usb/host/uhci-hcd.ko' [elf32-i386] to `/tmp/initrd.125242/lib/uhci-hcd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/fs/jbd/jbd.ko' [elf32-i386] to `/tmp/initrd.125242/lib/jbd.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/fs/ext3/ext3.ko' [elf32-i386] to `/tmp/initrd.125242/lib/ext3.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mod.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-mod.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-log.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-log.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mirror.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-mirror.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-zero.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-zero.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-snapshot.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-snapshot.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-mem-cache.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-mem-cache.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-region_hash.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-region_hash.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-message.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-message.ko' [elf32-i386]
copy from `/lib/modules/2.6.18-308.24.1.el5/kernel/drivers/md/dm-raid45.ko' [elf32-i386] to `/tmp/initrd.125242/lib/dm-raid45.ko' [elf32-i386]
/sbin/lvm.static -> /tmp/initrd.125242/bin/lvm
/sbin/dmraid.static -> /tmp/initrd.125242/bin/dmraid
/sbin/kpartx.static -> /tmp/initrd.125242/bin/kpartx
Adding module ehci-hcd
Adding module ohci-hcd
Adding module uhci-hcd
Adding module jbd
Adding module ext3
Adding module dm-mod
Adding module dm-log
Adding module dm-mirror
Adding module dm-zero
Adding module dm-snapshot
Adding module dm-mem-cache
Adding module dm-region_hash
Adding module dm-message
Adding module dm-raid45

The above got it booting but during init or after it says

INIT: Id "co" respawning too fast: disabled for 5 minutes

This is an easy fix, just edit:

vi /etc/inittab

Type: "/^co" or navigate to the line that has:

co:2345:respawn:/sbin/agetty xvc0 9600 vt100-nav

Comment the above line out, then uncomment the following which will be commented out below the co line:

1:2345:respawn:/sbin/mingetty tty1 2:2345:respawn:/sbin/mingetty tty2 3:2345:respawn:/sbin/mingetty tty3 4:2345:respawn:/sbin/mingetty tty4 5:2345:respawn:/sbin/mingetty tty5 6:2345:respawn:/sbin/mingetty tty6

After that, reboot and your conversion from Xen PV is over and your system should be working perfectly now.

As we can see, having a separate boot partition and LVM really complicate the migration process.

Tags:

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