Re: howto build debian xen kernel?
Jonas Meurer wrote:
On 06/02/2007 Grok Mogger wrote:
I didn't find any documentation about that topic. All howtos/tutorials/...
that talk about building a xen kernel, use the original xen kernel
sources, not the debian kernel source with patches.
You may have some need to compile your own kernel, but if you'd
be fine with a pre-made vanilla Debian kernel, you can just
install the appropriate Xen package. The right one will drop a
working Xen kernel in your /boot directory. As I recall, you'll
have to edit your GRUB menu.lst file and make an initrd with
update-initramfs afterwards. I think you want to pick one of
the packages that starts with "xen-hypervisor". There's a few
of them.
I hope this might save you some trouble.
Hello Grok,
I've installed xen-hypervisor-3.0.3-1-amd64, which includes
/boot/xen-3.0.3-1-amd64.gz.
Do i still need a xen-enabled host kernel, or may i use the current
self compiled kernel?
I saw that the current linux-source-2.6.18 from unstable contains a
menuconfig option 'Xen support'. I guess that i need to enable this,
and then use /boot/xen-3.0.3-1-amd64.gz as domain0 kernel.
Is that correct?
The description for xen-hypervisor-3.0-unstable-1-amd64 claims:
In order to boot a XEN system along with this package you also need a
kernel specifically crafted to work as the Domain 0, mediating hardware
access for XEN itself. An example config file for this kernel and
documentation on how to build it can be found in the xen-docs package.
But I cannot find any example kernel config in the xen-docs package.
greetings,
jonas
Hey Jonas,
Okay, first off....
[quoting]
The description for xen-hypervisor-3.0-unstable-1-amd64 claims:
In order to boot a XEN system along with this package you also
need a
kernel specifically crafted to work as the Domain 0, mediating
hardware
access for XEN itself. An example config file for this kernel and
documentation on how to build it can be found in the xen-docs
package.
But I cannot find any example kernel config in the xen-docs package.
[end quoting]
I know. Believe me, I know. That frustrated me to no end. I
never found any example kernel config either, nor did I find
instructions on how I was supposed to build this kernel that I
*supposedly* needed. In truth, it turned out that I never had
to build a kernel at all. Now is it just me, or does that text
not make it sound like you need to install the xen-hypervisor
package and then still take further steps to build a kernel?
Very misleading at best, flat out wrong at worst.
Anyway. Let's see if I can help...
"Do i still need a xen-enabled host kernel, or may i use the current
self compiled kernel?"
I'm not totally sure what you mean here... I think the short
answer is "yes", you're kernel needs to be xen-enabled.
"I saw that the current linux-source-2.6.18 from unstable contains a
menuconfig option 'Xen support'. I guess that i need to enable this,
and then use /boot/xen-3.0.3-1-amd64.gz as domain0 kernel.
Is that correct?"
I *think* so. I'm not totally sure I understand what you mean,
but I think you're on the right track. You have a self-compiled
kernel that you were using on a non-Xen system, and you want to
use it now with Xen? Is that it? Maybe it'll help if I just
show you what I did. I used all pre-packaged kernels that came
with Debian, no self-compiling at all. If you have some custom
kernel job you need, then maybe you can fill in the gaps around
what I did.
I did this on etch a while ago with Xen 3.0.2, and here's
basically what the process was. I hope I'm not missing
anything, I'm doing this from memory. =)
1) Install Xen-Hypervisor. This dropped a kernel in my boot
directory. "/boot/xen-3.0.2-1-i386.gz". You use this kernel
for both your Dom0 and your Guest Domains (DomU's). I guess it
also dropped a kernel called "vmlinuz-2.6.16-2-xen-686" in
/boot. Guess I forgot about that one. =P
2) Edit your "/boot/grub/menu.lst" file. I had to add an
option to boot into Xen. Here's what I added as a sample:
## ## End Default Options ##
title Xen 3.0 / XenLinux 2.6
kernel /boot/xen-3.0.2-1-i386.gz dom0_mem=256M console=vga
module /boot/vmlinuz-2.6.16-2-xen-686 root=/dev/md0 ro
console=tty0
module /boot/initrd.img-2.6.16-2-xen-686
savedefault
boot
3) I had to make the initrd you see there
("initrd.im-2.6.16-2-xen-686"). I recall trying yaird and it
not working. I did have success with update-initramfs. I can't
recall exactly what I did (sorry!), but I think it required the
xen kernel modules. I bet the xen-hypervisor package also
created a directory in "/lib/modules/" labeled something similar
to "2.6.16-2-xen-686" (my xen kernel modules). If not, you may
need to install another package to get those.
4) Now I seem to recall that being all I needed to boot into
Dom0. The one other thing (which may be "fixed" now) is that
when I tried doing any Xen commands (xm top and the like), I got
some error messages because xend wasn't running. I cannot
recall how I made it start up at boot, but it wasn't hard.
After all this, creating and getting a Guest to boot was another
long and complicated process. I could help you out with that
too if what I've written so far proves useful.
Hope this helps,
- GM
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