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Old 11-19-2008, 11:59 AM
"Matthew Walster"
 
Default Migration from VMWare to HP Blade

Hi all,
A few months ago, I migrated some of our internal servers to HP blades, as the VMWare box they were previously running on was getting too slow.
However, it wasn't without it's problems, and eventually the only way I could get them to work was:

Install the same version of CentOS on the blade (believed to be 5.0, but /etc/redhat-release says 5.2)Took down both servers, booting them off the SystemRescueCD, mounting all the partition on /mnt/transfer etc
Ran rsync to copy all the data from one to the other - except /boot and /lib/modulesBrought the blade up, and saw that it booted fine.
However, a new kernel has been released and we tried rebooting... And it panicked. It seems to be LVM related, in that it can't mount /dev/root - and I've tried manually running mkinitrd to regenerate the initrd to no avail.

I was just wondering if anyone had encountered similar problems, and knew of any solutions?
I'm from a debian background, so am a little unused to certain aspects - when a yum upgrade installs a new kernel, where does it pull the information for boot from? A configuration stanza from within grub's menu.lst?

Regards,


Matthew Walster
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Old 11-19-2008, 02:28 PM
"Lanny Marcus"
 
Default Migration from VMWare to HP Blade

On Wed, Nov 19, 2008 at 7:59 AM, Matthew Walster <matthew@walster.org> wrote:
> A few months ago, I migrated some of our internal servers to HP blades, as
> the VMWare box they were previously running on was getting too slow.
> However, it wasn't without it's problems, and eventually the only way I
> could get them to work was:
> Install the same version of CentOS on the blade (believed to be 5.0, but
> /etc/redhat-release says 5.2)
> Took down both servers, booting them off the SystemRescueCD, mounting all
> the partition on /mnt/transfer etc
> Ran rsync to copy all the data from one to the other - except /boot and
> /lib/modules
> Brought the blade up, and saw that it booted fine.
> However, a new kernel has been released and we tried rebooting... And it
> panicked. It seems to be LVM related, in that it can't mount /dev/root - and
> I've tried manually running mkinitrd to regenerate the initrd to no avail.
> I was just wondering if anyone had encountered similar problems, and knew of
> any solutions?
> I'm from a debian background, so am a little unused to certain aspects -
> when a yum upgrade installs a new kernel, where does it pull the information
> for boot from? A configuration stanza from within grub's menu.lst?

I think you will find that in /boot/grub/grub.conf

Other, far more knowledgeable people on the list will, hopefully,
answer your questions.
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Old 11-19-2008, 02:39 PM
"Matthew Walster"
 
Default Migration from VMWare to HP Blade

2008/11/19 Lanny Marcus <lmmailinglists@gmail.com>
I think you will find that in /boot/grub/grub.conf
$ mount/dev/cciss/c0d0p2 on / type ext3 (rw,noatime)
$ sudo cat /etc/grub/menu.list #symlinked to /etc/grub/grub.conf
# grub.conf generated by anaconda## Note that you do not have to rerun grub after making changes to this file# NOTICE: *You have a /boot partition. *This means that# * * * * *all kernel and initrd paths are relative to /boot/, eg.
# * * * * *root (hd0,0)# * * * * *kernel /vmlinuz-version ro root=/dev/cciss/c0d0p2# * * * * *initrd /initrd-version.img#boot=/dev/cciss/c0d0default=0timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gzhiddenmenutitle CentOS (2.6.18-92.1.17.el5)** * * *root (hd0,0)** * * *kernel /vmlinuz-2.6.18-92.1.17.el5 ro root=/dev/cciss/c0d0p2
** * * *initrd /initrd-2.6.18-92.1.17.el5.imgtitle CentOS (2.6.18-92.1.13.el5)** * * *root (hd0,0)** * * *kernel /vmlinuz-2.6.18-92.1.13.el5 ro root=/dev/cciss/c0d0p2** * * *initrd /initrd-2.6.18-92.1.13.el5.img
title CentOS (2.6.18-53.el5)** * * *root (hd0,0)** * * *kernel /vmlinuz-2.6.18-53.el5 ro root=LABEL=/1** * * *initrd /initrd-2.6.18-53.el5.img
$ uname -a
Linux (HOSTNAME) 2.6.18-53.el5 #1 SMP Mon Nov 12 02:14:55 EST 2007 x86_64 x86_64 x86_64 GNU/Linux
And yes, I've tried altering the root= lines to match the working kernel, but that didn't work either, and it gets overwritten anyway after every kernel upgrade.


Other, far more knowledgeable people on the list will, hopefully,

answer your questions.
Thanks
Matthew Walster*
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Old 11-19-2008, 02:45 PM
"Matthew Walster"
 
Default Migration from VMWare to HP Blade

2008/11/19 Matthew Walster <matthew@walster.org>
$ sudo cat /etc/grub/menu.list #symlinked to /etc/grub/grub.conf
I, of course, meant /boot/grub/menu.lst and /boot/grub/grub.conf

Matthew Walster*
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Old 11-19-2008, 05:31 PM
Kai Schaetzl
 
Default Migration from VMWare to HP Blade

Matthew Walster wrote on Wed, 19 Nov 2008 15:39:18 +0000:

> And yes, I've tried altering the root= lines to match the working kernel,
> but that didn't work either, and it gets overwritten anyway after every
> kernel upgrade.

change default to 1 if that was your working kernel. If that doesn't help
the problem is not what/where you think it is.

Kai

--
Kai Schätzl, Berlin, Germany
Get your web at Conactive Internet Services: http://www.conactive.com



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Old 11-19-2008, 06:12 PM
"Miskell, Craig"
 
Default Migration from VMWare to HP Blade

> Hi all,
>
> A few months ago, I migrated some of our internal servers to HP
> blades, as the VMWare box they were previously running on was getting
> too slow.
>
> However, it wasn't without it's problems, and eventually the only way I
> could get them to work was:
>
> Install the same version of CentOS on the blade (believed to be 5.0, but
> /etc/redhat-release says 5.2)
> Took down both servers, booting them off the SystemRescueCD,
> mounting all the partition on /mnt/transfer etc
> Ran rsync to copy all the data from one to the other - except /boot and
> /lib/modules
> Brought the blade up, and saw that it booted fine.
>
> However, a new kernel has been released and we tried rebooting... And
> it panicked. It seems to be LVM related, in that it can't mount /dev/root -
> and I've tried manually running mkinitrd to regenerate the initrd to no
> avail.
>
> I was just wondering if anyone had encountered similar problems, and
> knew of any solutions?
Having just done the opposite (test migrating a CentOS server from physical hardware to VMWare), I have a very good idea :-) It was CentOS 4, but the basic bits should be the same

You need to edit /etc/modprobe.conf, and change the line (or lines) that start with:
"alias scsi_hostadapter"

If the server was vmware, the existing lines are probably
alias scsi_hostadapter mptbase
alias scsi_hostadapter1 mptscsih

I'm not sure what you'll have to change mptbase and mptscsih to be; on HP servers, cciss is the correct driver. Others will vary (you could try a quick basic manual install on the target hardware and see what gets put in that file by the OS installer).

After you've changed modprobe.conf, re-run mkinitrd and reboot. Should be good to go. You'll also have to watch out for HWADDR in /etc/sysconfig/network-scripts/ifcfg-eth*, either changing it to match your new hardware, or removing it entirely. Kudzu will probably take care of sorting out the network card driver entries in modprobe; follow your nose and take a guess, you'll probably get it right. Either way, mkinitrd is only necessary (in this case) to get access to your root device

Hope that helps,
Craig Miskell

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Old 11-19-2008, 07:17 PM
"Lanny Marcus"
 
Default Migration from VMWare to HP Blade

On Wed, Nov 19, 2008 at 10:39 AM, Matthew Walster <matthew@walster.org> wrote:
> 2008/11/19 Lanny Marcus <lmmailinglists@gmail.com>
>> I think you will find that in /boot/grub/grub.conf
>
> $ mount
> /dev/cciss/c0d0p2 on / type ext3 (rw,noatime)
> $ sudo cat /etc/grub/menu.list #symlinked to /etc/grub/grub.conf
> # grub.conf generated by anaconda
> #
> # Note that you do not have to rerun grub after making changes to this file
> # NOTICE: You have a /boot partition. This means that
> # all kernel and initrd paths are relative to /boot/, eg.
> # root (hd0,0)
> # kernel /vmlinuz-version ro root=/dev/cciss/c0d0p2
> # initrd /initrd-version.img
> #boot=/dev/cciss/c0d0
> default=0
> timeout=5
> splashimage=(hd0,0)/grub/splash.xpm.gz
> hiddenmenu
> title CentOS (2.6.18-92.1.17.el5)
> root (hd0,0)
> kernel /vmlinuz-2.6.18-92.1.17.el5 ro root=/dev/cciss/c0d0p2
> initrd /initrd-2.6.18-92.1.17.el5.img
> title CentOS (2.6.18-92.1.13.el5)
> root (hd0,0)
> kernel /vmlinuz-2.6.18-92.1.13.el5 ro root=/dev/cciss/c0d0p2
> initrd /initrd-2.6.18-92.1.13.el5.img
> title CentOS (2.6.18-53.el5)
> root (hd0,0)
> kernel /vmlinuz-2.6.18-53.el5 ro root=LABEL=/1
> initrd /initrd-2.6.18-53.el5.img
> $ uname -a
> Linux (HOSTNAME) 2.6.18-53.el5 #1 SMP Mon Nov 12 02:14:55 EST 2007 x86_64
> x86_64 x86_64 GNU/Linux
> And yes, I've tried altering the root= lines to match the working kernel,
> but that didn't work either, and it gets overwritten anyway after every
> kernel upgrade.
>>
>> Other, far more knowledgeable people on the list will, hopefully,
>> answer your questions.
>
> Thanks

Matthew: You're welcome. As Kai wrote earlier, you need to change the
line that says default=n to the "title" line for the kernel you want
to use (I think it defaults to 0, after a Kernel upgrade). Every time
you install a new kernel, it will change this file, so you may need to
go back and tweak it, after a kernel upgrade. Lanny
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Old 11-20-2008, 10:44 AM
"Matthew Walster"
 
Default Migration from VMWare to HP Blade

2008/11/19 Miskell, Craig <Craig.Miskell@agresearch.co.nz>

> I was just wondering if anyone had encountered similar problems, and

> knew of any solutions?

Having just done the opposite (test migrating a CentOS server from physical hardware to VMWare), I have a very good idea *:-) *It was CentOS 4, but the basic bits should be the same

Thanks for that, I'll give it a go. It's been bugging me for some time.

When I get around to testing this (preferably when it's not a peak hour!) I'll come back and let you guys know if it worked, know if there's a place I can document it? It can't just be us two that have had this issue.

Matthew Walster
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Old 11-20-2008, 12:31 PM
Kai Schaetzl
 
Default Migration from VMWare to HP Blade

Matthew Walster wrote on Thu, 20 Nov 2008 11:44:36 +0000:

> It can't just be us two that have had this issue.

I don't have this issue. It was just standard advice on how you go back to
an older kernel.

> And yes, I've tried altering the root= lines to match the working kernel,

and I gave it after reading that line. It's easy to mistype or do something
else wrong to the file when editing that much. Just changing the default to
boot that supposed to be working kernel gives much less source for
mistakes. If it then still doesn't boot it's more likely that it's got
nothing to do with the kernel version.

Kai

--
Kai Schätzl, Berlin, Germany
Get your web at Conactive Internet Services: http://www.conactive.com



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Old 11-20-2008, 07:54 PM
Phil Schaffner
 
Default Migration from VMWare to HP Blade

Matthew Walster wrote:
...
When I get around to testing this (preferably when it's not a peak
hour!) I'll come back and let you guys know if it worked, know if
there's a place I can document it? It can't just be us two that have had
this issue.


You can reply to the list with SOLVED added to the subject line for
future searchers of the list archives. This is probably not general
enough to warrant a Wiki article, although there have been a lot of
recent questions about hardware/kernel changes causing hangups and
requiring tweaks to grub, modules.conf, and needing to mkinitrd - if
someone feels up to writing a more general guide to solving such problems.


Phil

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