Re: [gentoo-user] New kernel does not boot up on remote host

[Galevsky <galevsky@gmail.com>]

2007/7/5, Albert Hopkins <marduk@gentoo.org>:
> On Thu, 2007-07-05 at 11:36 +0200, Galevsky wrote:
> > Many thanks for you suggestion. I tried a boot with no fall back, but
> > nothing added neither to boot.log nor to dmesg. I am sure to target
> > the right kernel image with no typo into grub.conf . This new kernel
> > is a =xen-sources-2.6.16.49, and I configured it making an oldconfig
> > based on current =gentoo-sources-2.6.20 running kernel. So, errors
> > cannot come from drivers or such things, but specific xen options.
> > Does anyone know any xen option able to prevent the kernel to boot up
> > ?
>
> I guess I (still) don't understand what your issue is.  So I went back
> and read your original post.  Maybe I misunderstood it.
>
>       * What do you mean by "remote host"?

I rent a dedicated host. Thus, I have no physical access to the
machine. And the reason why I used the fall-back feature into grub is
to avoid the use of a boring rescue system (via a web interface) to
take back the control of a not-responding box.

>       * If your box "does not boot" how would you expect to see a
>         boot.log or dmesg ? They don't exist if the system has not
>         booted.  In fact "does not boot" implies that you can't even log
>         in to check for dmesg or boot logs.  Perhaps you can explain
>         what it is exactly you mean by "does not boot".

When I try to boot on the new kernel, I set it as the "default" one in
grub.conf and reboot the box. And I wait for a few minutes. Then I try
to log on, praying to find the box responding.

First, with grub fall-back activated, the boot had fallen back and I
was able to read the logs that contained the running kernel logs, but
no info about the kernel boot that failed. That was the matter of my
first mail: how to read  the reasons of the first kernel-boot-attempt
failure.

Secondly, you advised me to turn fall back off. I do. The box is no
more responding after reboot, and I have to launch the "rescue system"
to log on my box, and read the /var/log/*. I thought previously that
some pb happened -I didn't know when exactly-... and was waiting for
more info in log files. But files were empty. So, I conclude that the
boot procedure failed (and you too ;o)).

Finally, I have to find out why my kernel is not booting. I tuned up
well my previous kernel, a gentoo-sources-2.6.20 -this kernel runs
currently my box very well- and the kernel I want to boot now is a
xen-sources-2.6.16. I made an oldconfig on /proc/config.gz of the
2.6.20 running kernel, and fill in xen-dom0 specific options as
indicated on the wiki tutorial [1]. So, I guess I did something wrong
with the dom0 xen config, and asked for advice on xen specific options
with my second post.

>       * Usually there is an error message on the console if there is a
>         boot loader/kernel issue with booting.
>       * Also you never posted your grub.conf.
>
> So hopefully you can come up with a specific explanation of "does not
> boot" as well as your config and any console messages you get.  Else
> this becomes a "blind leading the blind" issue.

I have no console message to provide you, I just know that my remote
box is not responding when I try to boot another kernel (If you know
the way to get logs, I'll be grateful :o)). And I checked the
/var/log/* to be sure that the kernel was not running but just missing
any network feature so that I could not log on the box despite the
kernel was actually running.

As for my grub.conf + 'ls -l /boot' , I will provide you in a while (I
need to go home before), but I am not sure it is relevant. (just to
check for typo I guess).

> --
> Albert W. Hopkins
>
> --
> gentoo-user@gentoo.org mailing list

Many thanks to take care of my problem :o)

Gal'

[1]: http://gentoo-wiki.com/HOWTO_Xen_and_Gentoo
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