Re: [Xen-users] Xen 4.0 Custom kernels

[Net Warrior <netwarrior863@xxxxxxxxx>]

Well.. good news

I was able to boot the DomU server, I found an example in Virtuatoia  related to my problem, the trick was this

mkinitrd --omit-scsi-modules --with=xennet --with=xenblk --preload=xenblk, I was using mkinitrd without any parameters  only  -f to overwrite , path to the image and the kernel version, that was for the Dom0.

Now, I happy :D, lets rock.

Thanks for your time and support guys

Best Regards

2010/5/17 Net Warrior <netwarrior863@xxxxxxxxx>

Well.. I'm having the same error

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!

Pid: 1, comm: init Not tainted 2.6.31.13 #16
Call Trace:
[<c105beb6>] panic+0x46/0x100
[<c105e856>] do_exit+0x626/0x6d0
[<c105e931>] do_group_exit+0x31/0x90
[<c105e99f>] sys_exit_group+0xf/0x20
[<c102a069>] syscall_call+0x7/0xb

----

CONFIG_XEN_NETDEV_FRONTEND=m

CONFIG_XEN_BLKDEV_FRONTEND=m

config file 

disk = [ 'phy:VG-NW/root,xvda1,w','phy:VG-NW/swap,xvda2,w' ]

root = "/dev/xvda1 ro"

fstab for DomU

/dev/xvda1 / ext3 defaults 1 1
tmpfs /dev/shm tmpfs defaults 0 0
none /dev/pts devpts gid=5,mode=620 0 0
#devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/xvda2 swap swap defaults 0 0

Do not know what's missing, I'll keep trying.

Thanks for your time and support.

Best Regards

2010/5/17 Net Warrior <netwarrior863@xxxxxxxxx>

Hi There.

Thank you very much for your assistance, I'll try to compile it as module and give it a try , for sure I know is compiled embeded.

Will report as soon as I get some results.

Best Regards

2010/5/17 Pasi Kärkkäinen <pasik@xxxxxx>

On Mon, May 17, 2010 at 12:29:59AM -0300, Net Warrior wrote:
>    Hi There.

>    Sorry for the delay, here is the config file for DomU , Only the options I
>    modified, the rest is as it is, by default.
>    # Kernel image file.
>    kernel = "/boot/vmlinuz-2.6.31.13"
>
>    # Optional ramdisk.
>    ramdisk = "/boot/initrd-2.6.31.13.img"
>
>    memory = 64
>
>    # A name for your domain. All domains must have different names.
>    name = "Netwarrior"
>
>    vif = [ '' ]
>    disk = [ 'phy:VG-NW/root,sda1,w','phy:VG-NW/swap,sda2,w' ]
>    # Set root device.
>    root = "/dev/sda1 ro"
>

Wrong. You should be using xvda1 and xvda2 instead of sda1 and sda2.
pvops kernels only support xvd* disk names in the guest.

>    # Sets runlevel 4.
>    extra = "4"
>    How do I know which hardware Xen ( Dom0 ) is providing to the DomU ?
>

Also check the 2.6.31.13 kernel .config if xen-blkfront is built-in or compiled as a module.
If it's compiled as a module then you need to have an initrd that actually loads it!

-- Pasi

>    Thank you very much.
>    Regards

>    2010/5/14 Pasi Kärkkäinen <[1]pasik@xxxxxx>
>
>      On Fri, May 14, 2010 at 07:47:33AM -0300, Net Warrior wrote:
>      >    Hi There.
>      >    The hardware is the same, so I asume that the initramfs used for
>      Dom0
>      >    could be used for DomU as well
>      >
>
>      No, the hardware is not the same!
>
>      domU only has "virtual" hardware provided by Xen, which is totally
>      different
>      from the physical hardware dom0 has access to!
>
>      , and yes I specified the root partition in
>      >    the DomU config file as well something like root /dev/sda1 ro ,
>      should I
>      >    use xdev as well in there?
>      >    Thanks for your time and support.
>      >
>
>      Please paste your /etc/xen/<guest> cfgfile.
>
>      -- Pasi
>
>      >    Best Regards

>      >    2010/5/14 Pasi Kärkkäinen <[1][2]pasik@xxxxxx>

>      >
>      >      On Thu, May 13, 2010 at 07:40:51PM -0300, Net Warrior wrote:
>      >      > Hi there guys
>      >      >
>      >      > As a test, I started using the same kernel and initramfs like
>      in Dom0
>      >      > which i know it works, but when starting up DomU I've get.
>      >      >
>      >      > switchroot: mount failed: No such file or directory
>      >      > Kernel panic - not syncing: Attempted to kill init!
>      >      > Pid: 1, comm: init Not tainted 2.6.31.13 #14
>      >      >
>      >
>      >      So the dom0 initrd image is not suitable for domU, ie. it doesn't
>      load
>      >      xen block frontend driver.. most probably. So the domU kernel is
>      >      not able to access the virtual disks provided to it.
>      >      > I've got the same error while setting up Dom0 and was a problem
>      with
>      >      > the scsi modules which I included in the kernel and not in the
>      >      > initramfs, my bad !!
>      >      >
>      >      > My config file looks this.
>      >      >
>      >
>       #----------------------------------------------------------------------------
>      >      > # Kernel image file.
>      >      > kernel = "/boot/vmlinuz-2.6.31.13"
>      >      >
>      >      > # Optional ramdisk.
>      >      > ramdisk = "/boot/initrd-2.6.31.13.img"
>      >      >
>      >      > disk = [ 'phy:VG-NW/root,sda1,w','phy:VG-NW/swap,sda2,w' ]
>      >      >
>      >
>      >      You should use xvda1 and xvda2 here, not sda1 and sda2.
>      >      the sd* naming is deprecated for xen PV guests.
>      >      > Also copied the /lib/modules/kernel_version to the *guest*
>      partition.
>      >      >
>      >      > What am I missing?
>      >      >
>      >
>      >      You need to create an initrd image that is suitable for the domU.
>      >
>      >      Also did you specify root= parameter for the domU kernel?
>      >      -- Pasi
>      >
>      >      > Thanks for your time and support
>      >      > Regards
>      >      >
>      >      >
>      >      >
>      >      >
>      >      >
>      >      >
>      >      >
>      >      >

>      >      > 2010/5/13, Pasi Kärkkäinen <[2][3]pasik@xxxxxx>:

>      >      > > On Thu, May 13, 2010 at 02:38:40PM -0300, Net Warrior wrote:
>      >      > >> Hi Pasi.
>      >      > >>
>      >      > >> Did not know I could use the Vanila Kernel for DomU usage, I
>      >      thought
>      >      > >> it has to be patched somehow as well.. so good news, I'll
>      try to
>      >      > >> compile a custom one using the latest stable from

>      [3][4]kernel.org and

>      >      leave
>      >      > >> the Dom0 which is working as it is.
>      >      > >>
>      >      > >
>      >      > > I recommend using the latest stable 2.6.32.x kernel for the
>      domU.
>      >      > >
>      >      > > If you're building a 32bit domU kernel remember it needs to
>      be PAE
>      >      (64G mem
>      >      > > support),
>      >      > > otherwise you won't see the pvops Xen domU options at all in
>      the
>      >      kernel
>      >      > > configuration.
>      >      > >
>      >      > > There are no special requirements for 64bit domU kernel.
>      >      > >
>      >      > > -- Pasi
>      >      > >
>      >      > >> Thanks for your time and support
>      >      > >> Regards
>      >      > >>
>      >      > >>
>      >      > >>
>      >      > >>
>      >      > >>

>      >      > >> 2010/5/13, Pasi Kärkkäinen <[4][5]pasik@xxxxxx>:

>      >      > >> > On Thu, May 13, 2010 at 12:38:00PM -0300, Net Warrior
>      wrote:
>      >      > >> >>    Hi there guys.
>      >      > >> >>
>      >      > >> >>    I'm using CentOS 5.4, I was able to compile my custom
>      Dom0
>      >      kernel
>      >      > >> >> and
>      >      > >> >> boot
>      >      > >> >>    it, now I've got some doubts.
>      >      > >> >>
>      >      > >> >>    I'd like to compile a custom DomU image, the problem
>      is that
>      >      when I
>      >      > >> >> do,
>      >      > >> >>    make kernels KERNELS="linux-2.6-xen0 linux-2.6-xenU"
>      it tries
>      >      to
>      >      > >> >> download
>      >      > >> >>    the kernel
>      >      > >> >>    from the HG repository which seems to have old 2.6.18
>      >      kernels, I
>      >      > >> >> want
>      >      > >> >> to
>      >      > >> >>    use the GIT repository which is alrealdy downloaded
>      and is
>      >      the
>      >      > >> >> source I
>      >      > >> >>    used to complile Dom0 using
>      >      > >> >>    kernel 2.6.33.13.
>      >      > >> >>
>      >      > >> >
>      >      > >> > specifying KERNELS="linux-2.6-xen0 linux-2.6-xenU" will
>      compile
>      >      > >> > linux-2.6.18-xen,
>      >      > >> > that's how it should be.
>      >      > >> >
>      >      > >> > If you don't specify KERNELS= at all, then it'll build
>      >      linux-2.6.31.x
>      >      > >> > kernel.
>      >      > >> > Or alternatively you can specify KERNELS="linux-2.6-pvops"
>      to get
>      >      the
>      >      > >> > same
>      >      > >> > result.
>      >      > >> >
>      >      > >> >>    Question:
>      >      > >> >>    Which files do I have to modify or how do I have to
>      proceed
>      >      to
>      >      > >> >> achieve
>      >      > >> >>    what I want?
>      >      > >> >>
>      >      > >> >
>      >      > >> > Did you know you can use the *default* (vanilla)

>      [5][6]kernel.org

>      >      Linux
>      >      > >> > kernels as
>      >      > >> > Xen PV domU?
>      >      > >> > No patches needed for that, the upstream kernels will work
>      for
>      >      domU.
>      >      > >> >
>      >      > >> >>    Under /usr/src/xen-4.0.0/buildconfigs I can see some
>      files
>      >      which
>      >      > >> >> define
>      >      > >> >>    some stuff depending on what I chose but not sure if
>      it's
>      >      safe to
>      >      > >> >> mees
>      >      > >> >>    with this.
>      >      > >> >>
>      >      > >> >>    Thanks for your time and support.
>      >      > >> >
>      >      > >> > Hopefully that helps.
>      >      > >> >
>      >      > >> > -- Pasi
>      >      > >> >
>      >      > >> >
>      >      > >
>      >
>      > References
>      >
>      >    Visible links

>      >    1. mailto:[7]pasik@xxxxxx
>      >    2. mailto:[8]pasik@xxxxxx
>      >    3. [9]http://kernel.org/
>      >    4. mailto:[10]pasik@xxxxxx
>      >    5. [11]http://kernel.org/

>
> References
>
>    Visible links
>    1. mailto:pasik@xxxxxx
>    2. mailto:pasik@xxxxxx

>    3. mailto:pasik@xxxxxx
>    4. http://kernel.org/
>    5. mailto:pasik@xxxxxx
>    6. http://kernel.org/
>    7. mailto:pasik@xxxxxx
>    8. mailto:pasik@xxxxxx
>    9. http://kernel.org/
>   10. mailto:pasik@xxxxxx
>   11. http://kernel.org/

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