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Re: [Xen-users] Re: export single partitions to xen 3.1.2 domU

On Wed, 22 Apr 2009, Fajar A. Nugraha wrote:

On Wed, Apr 22, 2009 at 4:27 PM, Steven Timm <timm@xxxxxxxx> wrote:
Libvirt (for most purposes) is just a frontend. You can dump libvirt
altogether if you like (which is what I did) and manage domUs using xm
commands. That way (if you want to) it can be just like your previous

Are you suggesting that
xm create, which I always use to launch the domain,
behaves differently depending on whether libvirt is running or not?

No. What I'm saying is that if you don't like libvirt or have problems
using it, then don't use it.
xm will work regardless whether libvirt is available or not.

Which is why I told you earlier

"If by "convert" you mean "run these old dom0 on new version of dom0",
then you don't have to do anything. Old domU config should run just

Except that I want to move the kernel inside the domU and boot
using pygrub, which I wasn't doing on this system before.

Now we're getting somewhere : It's not related libvirt. At all. :)
pyggrub does NOT require libvrt to be available in any way, shape, or form.
Here's my domU config file, using similar disk layout as yours (e.g.
hda1 instead of hda, sda, or xvda)

memory = "500"
maxmem = "8000"


disk =  [
vif =   [
        'mac=00:16:3E:F3:AE:C0, bridge=br102',
vfb =['type=vnc,vnclisten=']

Here's /etc/fstab on that domU :
/dev/hda1               /                       ext3
defaults,noatime        1 1
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
sysfs                   /sys                    sysfs   defaults        0 0
/dev/hda2               swap                    swap    defaults        0 0

Here's /boot/grub/menu.lst (which is a symlink to grub.conf) on domU's fs
title Red Hat Enterprise Linux Server (2.6.18-128.1.6.el5xen)
        root (hd0,0)
        kernel /boot/vmlinuz-2.6.18-128.1.6.el5xen ro root=/dev/hda1
        initrd /boot/initrd-2.6.18-128.1.6.el5xen.img

Here's /etc/modprobe.conf (required to build initrd correctly)
alias eth0 xennet
alias scsi_hostadapter xenblk

After checking those files you either need to create initrd inside
domU, or copy dom0's initrd to domU.

Thanks a lot.  The right modprobe.conf and remaking the initrd
was the key.  I had actualy installed the new kernel-xen inside
the domU before the reboot, which triggers a mkinitrd but
without the right modprobe.conf it didnt' make it right.
One of my nodes is back up  in the new configuration
and the other one should be soon.


Here's anlother example, which is what I did to turn jailtime.org
image (which uses sda1) to a pygrub-supported domU:

You are right that if I try to start
the unmodified xen domU config on the new dom0  (with
disabled libvirtd) I can do it.
but if I try to change anything--
even shift to pygrub with same disk configuration, things don't work.

Again, problem not directly related to libvirt.



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Steven C. Timm, Ph.D  (630) 840-8525
timm@xxxxxxxx  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group Leader.

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