Kernel Update for Xen Dom0

[Steven Smith]

Hi,

Is there a "best practices" procedure for updating the xen Dom0 environment
(kernel)? The installation of Fedora 16 with xen 4 was a breeze and it has
been running and performing well for ~ eight Months.  Performing an update
on the Dom0 kernel, however, does not seem to be covered in the standard
documentation. Using Yum to update the kernel does not rebuild or change the
xen.gz and the new kernel will not boot the xen dom0.   Does anyone have any
experience with this?   

Best Regards, 

Steven

[Pasi Kärkkäinen]

On Mon, May 28, 2012 at 04:22:50PM +0200, Steven G. Smith wrote:
>     Hi,
>  
>     Is there a "best practices" procedure for updating the xen Dom0
>     environment (kernel)? The installation of Fedora 16 with xen 4 was a
>     breeze and it has been running and performing well for ~ eight Months.
>     Performing an update on the Dom0 kernel, however, does not seem to be
>     covered in the standard documentation. Using Yum to update the kernel does
>     not rebuild or change the xen.gz and the new kernel will not boot the xen
>     dom0.   Does anyone have any experience with this?
>   
I think you need to edit /etc/default/grub

GRUB_DEFAULT="Xen"
GRUB_CMDLINE_XEN="dom0_mem=1024M loglvl=all guest_loglvl=all"

Or whatever settings you need for your environment.
Then run: grub2-mkconfig -o /boot/grub2/grub.cfg

That should do it.

-- Pasi

[Steven Smith]

>  Date: Mon, 28 May 2012 22:04:24 +0300
>  From: pasik(a)iki.fi
>  To: stevengs(a)hotmail.com
>  CC: xen(a)lists.fedoraproject.org
>  Subject: Re: [Fedora-xen] Kernel Update for Xen Dom0
>  
>  On Mon, May 28, 2012 at 04:22:50PM +0200, Steven G. Smith wrote:
>  >    Hi,
>  > 
>  >    Is there a "best practices" procedure for updating the xen Dom0
>  >    environment (kernel)? The installation of Fedora 16 with xen 4 was a
>  >    breeze and it has been running and performing well for ~ eight Months.
>  >    Performing an update on the Dom0 kernel, however, does not seem to be
>  >    covered in the standard documentation. Using Yum to update the kernel does
>  >    not rebuild or change the xen.gz and the new kernel will not boot the xen
>  >    dom0.   Does anyone have any experience with this?
>  > 
>  
>  I think you need to edit /etc/default/grub
>  
>  GRUB_DEFAULT="Xen"
>  GRUB_CMDLINE_XEN="dom0_mem=1024M loglvl=all guest_loglvl=all"
>  
>  Or whatever settings you need for your environment.
>  Then run: grub2-mkconfig -o /boot/grub2/grub.cfg
>  
>  That should do it.
>  
>  -- Pasi
>   
Hi Pasi,  Thanks for your support.  It is not an issue with Grub (as far as i can
tell).  I appended the standard grub command line defaults with pcie-aspx=off at initial
install, due to some issues I have with my Mobo/HBA combination.   RUB_TIMEOUT=5
GRUB_DISTRIBUTOR="Fedora"
GRUB_DEFAULT=saved
GRUB_CMDLINE_LINUX="rd.md=0 rd.dm=0  KEYTABLE=de quiet SYSFONT=latarcyrheb-sun16 rhgb
rd.luks=0 rd.lvm.lv=vg_myserver/lv_myserver_root rd.lvm.lv=vg_myserver/lv_myserver_swap
LANG=en_US.UTF-8 pcie_aspm=off"
 When i update the kernel with yum, the kernel is built, the (many) grub entries are added
(all appended correctly).  Everything looks good.  I can boot the non-xen kernel fine..
starts up, correct version of kernel.  But starting the new xen dom0 kernel does not work.
 It just hangs, even with manual command-line entries.  I can boot the old xen dom0 kernel
without any problems, and it runs as before.  What is held in the xen-4.1.x.gz file?  I
had expected this gz to be rebuilt or at least touched.. but it is not.  What are the
usual steps required to upgrade the dom0 kernel manually?  Must it be done from the
xendom0 or the stand alone kernel?  Are any special steps needed?  (yum update is
apparently insufficient).  Is there a special order to be adhered to? uname
(current):Linux myserver.mydomain.local 3.2.1-3.fc16.x86_64 #1 SMP Mon Jan 23 15:36:17 UTC
2012 x86_64 x86_64 x86_64 GNU/Linux xm info: (current):
host                   : myserver.mydomain.local
release                : 3.2.1-3.fc16.x86_64
version                : #1 SMP Mon Jan 23 15:36:17 UTC 2012
machine                : x86_64
nr_cpus                : 4
nr_nodes               : 1
cores_per_socket       : 4
threads_per_core       : 1
cpu_mhz                : 3110
hw_caps                :
178bf3ff:efd3fbff:00000000:00001310:00802001:00000000:000037ff:00000000
virt_caps              : hvm
total_memory           : 7934
free_memory            : 2
free_cpus              : 0
xen_major              : 4
xen_minor              : 1
xen_extra              : .2
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p
hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
xen_commandline        : placeholder
cc_compiler            : gcc version 4.6.2 20111027 (Red Hat 4.6.2-1) (GCC)
cc_compile_by          : mockbuild
cc_compile_domain      : phx2.fedoraproject.org
cc_compile_date        : Fri Feb  3 22:02:40 UTC 2012
xend_config_format     : 4
 the newly compiled non-booting kernel is:  3.3.1-3.fc16.x86_64   Best Regards,Steven

[Pasi Kärkkäinen]

On Tue, May 29, 2012 at 01:38:09PM +0200, Steven Smith wrote:
>  
>     When i update the kernel with yum, the kernel is built, the (many) grub
>     entries are added (all appended correctly).  Everything looks good.  I can
>     boot the non-xen kernel fine.. starts up, correct version of kernel.  But
>     starting the new xen dom0 kernel does not work.  It just hangs, even with
>     manual command-line entries.  I can boot the old xen dom0 kernel without
>     any problems, and it runs as before.  What is held in the xen-4.1.x.gz
>     file?  I had expected this gz to be rebuilt or at least touched.. but it
>     is not.  What are the usual steps required to upgrade the dom0 kernel
>     manually?  Must it be done from the xendom0 or the stand alone kernel?
>     Are any special steps needed?  (yum update is apparently insufficient).
>     Is there a special order to be adhered to?
>  
>     uname (current):
>     Linux myserver.mydomain.local 3.2.1-3.fc16.x86_64 #1 SMP Mon Jan 23
>     15:36:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
>  
>     the newly compiled non-booting kernel is:  3.3.1-3.fc16.x86_64
>   
Oh, yes, the latest kernel has some bug when running as dom0.
I wonder if it's this one: https://bugzilla.redhat.com/show_bug.cgi?id=804347

Konrad probably knows/remembers..

Meanwhile you should set up a serial console so you can capture the crash logs:
http://wiki.xen.org/wiki/XenSerialConsole

So please post the full Xen hypervisor + dom0 Linux kernel verbose debug log here.

-- Pasi

[Konrad Rzeszutek Wilk]

On Tue, May 29, 2012 at 03:29:48PM +0300, Pasi Kärkkäinen wrote:
>  On Tue, May 29, 2012 at 01:38:09PM +0200, Steven Smith wrote:
>  > 
>  >    When i update the kernel with yum, the kernel is built, the (many) grub
>  >    entries are added (all appended correctly).  Everything looks good.  I can
>  >    boot the non-xen kernel fine.. starts up, correct version of kernel.  But
>  >    starting the new xen dom0 kernel does not work.  It just hangs, even with
>  >    manual command-line entries.  I can boot the old xen dom0 kernel without
>  >    any problems, and it runs as before.  What is held in the xen-4.1.x.gz
>  >    file?  I had expected this gz to be rebuilt or at least touched.. but it
>  >    is not.  What are the usual steps required to upgrade the dom0 kernel
>  >    manually?  Must it be done from the xendom0 or the stand alone kernel?
>  >    Are any special steps needed?  (yum update is apparently insufficient).
>  >    Is there a special order to be adhered to?
>  > 
>  >    uname (current):
>  >    Linux myserver.mydomain.local 3.2.1-3.fc16.x86_64 #1 SMP Mon Jan 23
>  >    15:36:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
>  > 
>  >    the newly compiled non-booting kernel is:  3.3.1-3.fc16.x86_64
>  > 
>  
>  Oh, yes, the latest kernel has some bug when running as dom0.
>  I wonder if it's this one: https://bugzilla.redhat.com/show_bug.cgi?id=804347 
I think it is. I just booted vmlinuz-3.3.6-3.fc16.x86_64 and it had no such
trouble.

>  
>  Konrad probably knows/remembers..
>  
>  Meanwhile you should set up a serial console so you can capture the crash logs:
>  http://wiki.xen.org/wiki/XenSerialConsole
>  
>  So please post the full Xen hypervisor + dom0 Linux kernel verbose debug log here.
>  
>  -- Pasi
>  
>  --
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