Xen users - Apr 2009 - export single partitions to xen 3.1.2 domU

I have some old xen instances which were installed under
Xen 3.1.0 with the following Disk configuration

disk = [ ''phy:LG0/LV11,sda1,w'',
''phy:LG0/LV12,sda2,w'',''phy:LG0/LV13,sda3,w''
]

Each one of these is a single partition, with a single file system.

I am now trying to run redhat/centos/scientific linux 5.2 and convert
these old domU''s over.

I run a lot of stuff on redhat/centos/scientific linux but
I have used the virt-manager to install all of them, and they are
all set up using the xvda type file system in which each exported
partition has got a partition table.
disk = [ "phy:/dev/LG0/LV0,xvda,w",
"phy:/dev/LG0/LV16,xvdb,w" ]


Is there any way to mountt single partitions
  under the new software, if so, how?

I tried to export the three partitions above as xvda,xvdb, xvdc
and change the fstab and the grub information in domU accordingly,
no luck

I also tried to just do things as before with sda1,sda2,sda3,
also no luck.

In all cases  I get this error

mount: could not find filesystem ''/dev/root''
Setting up other filesystems.
Setting up new root fs
setuproot: moving /dev failed: No such file or directory
no fstab.sys, mounting internal defaults
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Switching to new root and running init.
unmounting old /dev
unmounting old /proc
unmounting old /sys
switchroot: mount failed: No such file or directory
Kernel panic - not syncing: Attempted to kill init!

---

I suppose I could move all existing file systems to new ones
of the new format but would really like to avoid that if I can.

Steve Timm


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

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On Wed, Apr 22, 2009 at 11:20 AM, Steven Timm <timm@fnal.gov>
wrote:
>
> I have some old xen instances which were installed under
> Xen 3.1.0 with the following Disk configuration
>
> disk = [ ''phy:LG0/LV11,sda1,w'',
''phy:LG0/LV12,sda2,w'',''phy:LG0/LV13,sda3,w''
> ]
>
> Each one of these is a single partition, with a single file system.
>
> I am now trying to run redhat/centos/scientific linux 5.2 and convert
> these old domU''s over.
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
fine.
> disk = [ "phy:/dev/LG0/LV0,xvda,w",
"phy:/dev/LG0/LV16,xvdb,w" ]
>
>
> Is there any way to mountt single partitions
>  under the new software, if so, how?
If your question is "how to mount these new domU fs on dom0", then
it''s a bit tricky.
One possible solution:
http://lists.xensource.com/archives/html/xen-users/2009-01/msg00718.html

Another alternative is to map that disk to dom0. Something like :
- shutdown domU
- modprobe xenblk
- xm block-attach 0 phy:/dev/LG0/LV0 xvda w

This should give you xvda on dom0, along with its partitions (xvda1,
xvda2, etc.). After you''re done using it, detach the block device with
"xm block-list" and "xm block-detach"

Regards,

Fajar

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Just as a clarification, as I read the various manuals,
it seems that the key difference is that
the enterprise linux 5.2/xen 3.1.2 (labeled 3.0.3 as it comes from Redhat) 
is running libvirt, and my previous setup that I''m trying to
upgrade to that was not.

So does anyone know how to export a single partition to a
libvirt-enabled xen domU that''s otherwise installed already, or
how to take a non-libvirt domU with 3 such partitions and turn it
into one that is\

Steve


On Tue, 21 Apr 2009, Steven Timm wrote:
>> I have some old xen instances which were installed under
> Xen 3.1.0 with the following Disk configuration
>
> disk = [ ''phy:LG0/LV11,sda1,w'',
''phy:LG0/LV12,sda2,w'',''phy:LG0/LV13,sda3,w''
]
>
> Each one of these is a single partition, with a single file system.
>
> I am now trying to run redhat/centos/scientific linux 5.2 and convert
> these old domU''s over.
>
> I run a lot of stuff on redhat/centos/scientific linux but
> I have used the virt-manager to install all of them, and they are
> all set up using the xvda type file system in which each exported
> partition has got a partition table.
> disk = [ "phy:/dev/LG0/LV0,xvda,w",
"phy:/dev/LG0/LV16,xvdb,w" ]
>
>
> Is there any way to mountt single partitions
> under the new software, if so, how?
>
> I tried to export the three partitions above as xvda,xvdb, xvdc
> and change the fstab and the grub information in domU accordingly,
> no luck
>
> I also tried to just do things as before with sda1,sda2,sda3,
> also no luck.
>
> In all cases  I get this error
>
> mount: could not find filesystem ''/dev/root''
> Setting up other filesystems.
> Setting up new root fs
> setuproot: moving /dev failed: No such file or directory
> no fstab.sys, mounting internal defaults
> setuproot: error mounting /proc: No such file or directory
> setuproot: error mounting /sys: No such file or directory
> Switching to new root and running init.
> unmounting old /dev
> unmounting old /proc
> unmounting old /sys
> switchroot: mount failed: No such file or directory
> Kernel panic - not syncing: Attempted to kill init!
>
> ---
>
> I suppose I could move all existing file systems to new ones
> of the new format but would really like to avoid that if I can.
>
> Steve Timm
>
>
> ------------------------------------------------------------------
> Steven C. Timm, Ph.D  (630) 840-8525
> timm@fnal.gov  http://home.fnal.gov/~timm/
> Fermilab Computing Division, Scientific Computing Facilities,
> Grid Facilities Department, FermiGrid Services Group, Assistant Group
Leader.
>
-- 
------------------------------------------------------------------
Steven C. Timm, Ph.D  (630) 840-8525
timm@fnal.gov  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group Leader.

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

On Wed, Apr 22, 2009 at 3:39 PM, Steven Timm <timm@fnal.gov>
wrote:
> Just as a clarification, as I read the various manuals,
> it seems that the key difference is that
> the enterprise linux 5.2/xen 3.1.2 (labeled 3.0.3 as it comes from Redhat)
> is running libvirt, and my previous setup that I''m trying to
> upgrade to that was not.
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
setup.
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
fine."
>
> So does anyone know how to export a single partition to a
> libvirt-enabled xen domU that''s otherwise installed already, or
First method is to shutdown domU and edit its config file. They''re
still located under /etc/xen.
Second method is to use "xm block-attach" (or virsh attach-disk). You
may still have to edit the config file afterwards.
> how to take a non-libvirt domU with 3 such partitions and turn it
> into one that is\
Put the config file on /etc/xen, run "xm create" or "xm new"

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On Wed, 22 Apr 2009, Fajar A. Nugraha wrote:
> On Wed, Apr 22, 2009 at 3:39 PM, Steven Timm <timm@fnal.gov> wrote:
>> Just as a clarification, as I read the various manuals,
>> it seems that the key difference is that
>> the enterprise linux 5.2/xen 3.1.2 (labeled 3.0.3 as it comes from
Redhat)
>> is running libvirt, and my previous setup that I''m trying to
>> upgrade to that was not.
>
> 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
> setup.
Are you suggesting that
xm create, which I always use to launch the domain,
behaves differently depending on whether libvirt is running 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
> fine."
>
Except that I want to move the kernel inside the domU and boot
using pygrub, which I wasn''t doing on this system before.

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.

Ideas?

>>
>> So does anyone know how to export a single partition to a
>> libvirt-enabled xen domU that''s otherwise installed already,
or
>
> First method is to shutdown domU and edit its config file. They''re
> still located under /etc/xen.
That''s what I''m trying.. there is no way to get any sda device
to show up at all.  Would it be different if I stopped libvirt?
> Second method is to use "xm block-attach" (or virsh attach-disk).
You
> may still have to edit the config file afterwards.
virsh attach-disk according to its man page says that
this will make a full disk which still has to be formatted
and partitioned.  Is this not the case?
>
>> how to take a non-libvirt domU with 3 such partitions and turn it
>> into one that is\
>
> Put the config file on /etc/xen, run "xm create" or "xm
new"
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>
-- 
------------------------------------------------------------------
Steven C. Timm, Ph.D  (630) 840-8525
timm@fnal.gov  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group Leader.

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

On Wed, Apr 22, 2009 at 4:27 PM, Steven Timm <timm@fnal.gov>
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
>> setup.
>
> 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
>> fine."
>>
> 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"

vcpus=8
vcpu_avail=1
cpus="1-7"

disk =	[
	''phy:/dev/rootVG/radrootlv,hda1,w'',
	''phy:/dev/rootVG/radswaplv,hda2,w'',
	]
vif =	[
	''mac=00:16:3E:F3:AE:C0, bridge=br102'',
	]
vfb =[''type=vnc,vnclisten=0.0.0.0'']
bootloader="/usr/bin/pygrub"
#================================
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
#================================default=0
timeout=5
hiddenmenu
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.

Here''s anlother example, which is what I did to turn jailtime.org
image (which uses sda1) to a pygrub-supported domU:
http://lists.xensource.com/archives/html/xen-users/2009-03/msg00372.html
> 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.

Regards,

Fajar

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On Wed, 22 Apr 2009, Fajar A. Nugraha wrote:
> On Wed, Apr 22, 2009 at 4:27 PM, Steven Timm <timm@fnal.gov> 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
>>> setup.
>>
>> 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
>>> fine."
>>>
>> 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"
>
> vcpus=8
> vcpu_avail=1
> cpus="1-7"
>
> disk =	[
> 	''phy:/dev/rootVG/radrootlv,hda1,w'',
> 	''phy:/dev/rootVG/radswaplv,hda2,w'',
> 	]
> vif =	[
> 	''mac=00:16:3E:F3:AE:C0, bridge=br102'',
> 	]
> vfb =[''type=vnc,vnclisten=0.0.0.0'']
> bootloader="/usr/bin/pygrub"
> #================================>
> 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
> #================================> default=0
> timeout=5
> hiddenmenu
> 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.

Steve
Timm



>
> Here''s anlother example, which is what I did to turn jailtime.org
> image (which uses sda1) to a pygrub-supported domU:
> http://lists.xensource.com/archives/html/xen-users/2009-03/msg00372.html
>
>> 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.
>
> Regards,
>
> Fajar
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>
-- 
------------------------------------------------------------------
Steven C. Timm, Ph.D  (630) 840-8525
timm@fnal.gov  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group Leader.


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