CentOS virt - Sep 2012 - How do boot a xen domu into run level 1

Hi,

I have a C5.8 machine with several DomU's. I fubared the fstab on one of
them
and I need to get it into single user mode.

Does anyone know how to do that? I tried adding single to the extras line
in /etc/xen/machine_name but it still tries to start in level 3.

To make things worse, the root partition is on LVM.

Alternatively, does anyone know how to access the image from DomU? I tried
to use kpartx but when I run VGscan, I do not get the lvm activated.

Regards,

-- 
Tom			me at tdiehl.org		Spamtrap address	 		me123 at tdiehl.org

You could loop mount the messed up disk on the host or you could mount
the messed up disk on another DomU and change it.

On Thu, 2012-09-20 at 08:58 -0400, me at tdiehl.org
wrote:
> Hi,
> 
> I have a C5.8 machine with several DomU's. I fubared the fstab on one
of them
> and I need to get it into single user mode.
> 
> Does anyone know how to do that? I tried adding single to the extras line
> in /etc/xen/machine_name but it still tries to start in level 3.
> 
> To make things worse, the root partition is on LVM.
> 
> Alternatively, does anyone know how to access the image from DomU? I tried
> to use kpartx but when I run VGscan, I do not get the lvm activated.
> 
> Regards,
>

I am using pygrub to boot and this is how I got it to work:

  xm create -c <path to >dev3.cfg

at the boot splash select the kernel you are using to boot with..
press e to edit.
press e and edit the kernel line and put single right after the kernel 
designation....

i.e.   kernel /vmlinuz-2.6.18-274.3.1.el5xen single ro 
root=/dev/VolGroup00/LogVol00 .....
press enter to save your change.
It will return back to the  boot option menu

     pyGRUB  version 0.6
  ??????????????????????????????????????????????????????????????????????????
  ? kernel /vmlinuz-2.6.18-274.3.1.el5xen single ro 
root=/dev/VolGroup00/>               ?
  ? initrd /initrd-2.6.18-274.3.1.el5xen.img          ?
  ? ?
  ? ?
  ? ?
  ? ?
  ? ?
  ? ?
  ??????????????????????????????????????????????????????????????????????????
      Use the ^ and v keys to select which entry is highlighted.
      Press 'b' to boot, 'e' to edit the selected command in the
      boot sequence, 'c' for a command-line, 'o' to open a new
line
      after ('O' for before) the selected line, 'd' to remove
the
      selected line, or escape to go back to the main menu.

hit b to boot...


it worked for me a couple of times in succession.

Good luck.


-- 

Kevin Coleman - Network Engineer
kevin.coleman at laser2mail.com
LaserImage

On 09/20/2012 10:48 AM, Ed Heron wrote:
>    You could loop mount the messed up disk on the host or you could mount
> the messed up disk on another DomU and change it.
>
> On Thu, 2012-09-20 at 08:58 -0400, me at tdiehl.org wrote:
>> Hi,
>>
>> I have a C5.8 machine with several DomU's. I fubared the fstab on
one of them
>> and I need to get it into single user mode.
>>
>> Does anyone know how to do that? I tried adding single to the extras
line
>> in /etc/xen/machine_name but it still tries to start in level 3.
>>
>> To make things worse, the root partition is on LVM.
>>
>> Alternatively, does anyone know how to access the image from DomU? I
tried
>> to use kpartx but when I run VGscan, I do not get the lvm activated.
>>
>> Regards,
>>
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> http://lists.centos.org/mailman/listinfo/centos-virt
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On Thu, 20 Sep 2012, Kevin Coleman wrote:
> I am using pygrub to boot and this is how I got it to work:
>
> xm create -c <path to >dev3.cfg
>
> at the boot splash select the kernel you are using to boot with..
> press e to edit.
> press e and edit the kernel line and put single right after the kernel 
> designation....
>
> i.e.   kernel /vmlinuz-2.6.18-274.3.1.el5xen single ro 
> root=/dev/VolGroup00/LogVol00 .....
> press enter to save your change.
> It will return back to the  boot option menu
>
>    pyGRUB  version 0.6
> ??????????????????????????????????????????????????????????????????????????
> ? kernel /vmlinuz-2.6.18-274.3.1.el5xen single ro root=/dev/VolGroup00/>
> ?
> ? initrd /initrd-2.6.18-274.3.1.el5xen.img          ?
> ? ?
> ? ?
> ? ?
> ? ?
> ? ?
> ? ?
> ??????????????????????????????????????????????????????????????????????????
>     Use the ^ and v keys to select which entry is highlighted.
>     Press 'b' to boot, 'e' to edit the selected command in
the
>     boot sequence, 'c' for a command-line, 'o' to open a
new line
>     after ('O' for before) the selected line, 'd' to remove
the
>     selected line, or escape to go back to the main menu.
>
> hit b to boot...
>
>
> it worked for me a couple of times in succession.
Hummmmm, according to the config file, I too am using pygrub but I never see
the menu.

I tried the xm create command as you suggested but I still do not see the menu.

If I use virt-manager to make changes to the configuration, I see the
changes in /etc/xen/vm_name

I am now wondering if there is another config file some where that virt-manager
is writing to.

Am I missing something?

Regards,

-- 
Tom			me at tdiehl.org		Spamtrap address	 		me123 at tdiehl.org