Re: [Xen-users] K/Ubuntu 11.04 and XEN 4.1 - Possible?

[Mark Dokter <dokter@xxxxxxxxxxxxx>]

On 05/19/2011 07:22 AM, Fajar A. Nugraha wrote:
> On Thu, May 19, 2011 at 11:41 AM, Outback Dingo <outbackdingo@xxxxxxxxx> 
> wrote:
>>
>>
>> On Thu, May 19, 2011 at 12:30 AM, Fajar A. Nugraha <list@xxxxxxxxx> wrote:
>>>
>>> On Thu, May 19, 2011 at 11:23 AM, Outback Dingo <outbackdingo@xxxxxxxxx> 
>>> wrote:
>>>>
>>>> Ok running Kubuntu 11.04, is it possible to get XEN 4.1 installed to 
>>>> virtual a laptop running Kubuntu ?
>>>
>>> The generic answer would be "yes, if you compile xen hypervisor, tools, and 
>>> dom0 kernel from source".
>>> AFAIK there's no packaged version (yet) for either Debian or Ubuntu with 
>>> complete features (e.g. no tap: support in Debian's dom0 kernel)
>>
>> Well there is this...   
>> https://launchpad.net/~dokter/+archive/xen-4.1/+build/2492795
> 
> 
> Worth to try. Let us know how it goes.
> Although judging from package names and sizes, it still doesn't
> include dom0 kernel yet, so you have to compile it manually.
> 

Hey there!
I wanted to announce that ppa to the list already, but I didn't since
there are still some issues. Now that somebody seems to be willing to
try this stuff I'll drop some notes on my experiences:

The packages are basically the same as in debian unstable. I just
grabbed the source and recompiled it in a natty environment.
The only changes I made are:
- LIBS="" in the rules file, to get rid of some linker errors while
compiling
- added qemu-common as a dependency because /usr/share/qemu is provided
by that package in ubuntu.

The issues (which can be circumvented if known) are:
- Don't search for /etc/init.d/xencommons (as mentioned by xen
documentation) because the debianized init scripts don't use that (but
they work well by starting all daemons needed by xm and xl commands).

- The packages don't create the /var/lib/xen directory. Just create it
yourself.

- The xl command doesn't play nicely (it does on debian unstable though):
  * xl create <config> doesn't work with file:/<path-to-img>
configuration. Error message is:
qemu: could not open vbd '/local/domain/0/backend/vbd/7/51744/mode' or
hard disk image '/dev/xen/blktap-2/tapdev0' (drv 'phy' format 'raw')

(I was wondering about "drv 'phy'" although I specified file:/)

  * xl create <config> works when used with phy:/<path-to-dev> but
strangely the networking is troublesome in this scenario: The vifX.0
device in dom0 gets removed from the bridge after the domU is booted.
This can be fixed by a 'brctl addif <bridge-dev> vifX.0' and 'ifconfig
vifX.0 up'

- The xm commands work well. So until the strange behaviour of xl is
sorted out, use that.

- There's no kernel image provided by the ppa. I got some errors when I
tried to port the debian kernel image and didn't get around to figure
out how to make my own kernel source package that could be compiled by
launchpad service.

- The kernel image shouldn't be that hard to create:
  * grab the git source from the xen/stable-2.6.32.x tree
  * use ubuntu kernel config as a base (should have all settings needed
by your laptop) and add the necessary xen options.
  * use 'fakeroot make-kpkg --initrd --append-to-version=<whatever>
--revision=<whatever> kernel-image kernel-headers
  * this gives you a linux-image and a linux-headers package that should
work just fine


>>>>
>>>> I seriously dont want to use Vbox or KVM
>>>
>>> Why?
>>
>> Vbox and FreeBSD CURRENT dont play well, and i run XEN / XCP in the lab no 
>> sense in using multiple technologies
>>
> 
> AFAIK when you enable VT and use general hardware (e.g. PIIX IDE
> controller) in virtualbox, it should be similar to XEN HVM (when
> running without PV drivers) or KVM, so you might be able to reuse the
> same guest image for any virtualization technology.
> 

I'd recommend a desktop virtualisation like vbox too for virtualizing on
a desktop system. I tried to use xen on my workstation for testing
purposes, but ran into some troubles with the nvidia binary driver.

>>>
>>>
>>>>
>>>> , and need to run other OS for development, so XEN virtualization
>>>> on a 8 core laptop with 16 gig memory seem the best bet for mobile 
>>>> development
>>>
>>> Since it's a laptop, I actually suggest you just use 64bit OS and 
>>> virtualbox. Saves lots of headache.
>>
>> Currently running 64bit Kubuntu, just need XEN on it
> 
> Usually the hardest part is dom0 kernel. Here's the kernel config I
> use for RHEL5 dom0, you might be able to reuse some part of it:
> http://pastebin.com/vvqmb5sN (except CONFIG_SYSFS_DEPRECATED and
> CONFIG_SYSFS_DEPRECATED_V2. It's only needed for older userland like
> RHEL5).
> 
> The wiki is somewhat outdated, but you might be able to find some
> useful info there: http://wiki.xensource.com/xenwiki/XenParavirtOps
> 

That's a good source. Additionally, [1] was also very useful to me.
There are many different os/virtalization combinations described by that
blog. Unfortunately xen 4.1 got less attention there lately.

> Judging from other posts on this list, the usual question that comes
> afterward is "how to enable hardware acceleration for graphic card
> (e.g. nvidia)" or "how to passthrough the graphic card to a Windows
> domU". Both of which are problematic right now. That's why I suggested
> you use Virtualbox.
> 
> In any case, good luck, let us know how it goes.
> 

I wish you good luck too - especially if you try my xen packages, I'd
like to hear about it :)

> --
> Fajar
> 

hth, Mark

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