[virt-tools-list] Re: [libvirt] Create a new VM from an existent image?

[Cole Robinson]

Jun Koi wrote:
> On Tue, Jul 21, 2009 at 11:40 AM, Cole Robinson<crobinso at redhat.com> wrote:
>> Jun Koi wrote:
>>> On Tue, Jul 21, 2009 at 11:07 AM, Jun Koi<junkoi2004 at gmail.com> wrote:
>>>> On Tue, Jul 21, 2009 at 10:45 AM, Jun Koi<junkoi2004 at gmail.com> wrote:
>>>>> On Mon, Jul 20, 2009 at 1:19 AM, Cole Robinson<crobinso at redhat.com> wrote:
>>>>>> (taking to virt-tools-list, this isn't relevant to libvirt)
>>>>>>
>>>>>> Jun Koi wrote:
>>>>>>> On Sun, Jul 19, 2009 at 1:59 AM, Cole Robinson<crobinso at redhat.com> wrote:
>>>>>>>> Jun Koi wrote:
>>>>>>>>> On Fri, Jul 17, 2009 at 10:42 PM, Cole Robinson<crobinso at redhat.com> wrote:
>>>>>>>>>> Jun Koi wrote:
>>>>>>>>>>> Hi,
>>>>>>>>>>>
>>>>>>>>>>> To use libvirt, I am strying to use virt-install to create a new VM
>>>>>>>>>>> from an existent (KVM) VM image. I did the following steps:
>>>>>>>>>>>
>>>>>>>>>>> 1) run libvirtd with "libvirtd -d" (I use the latest libvirt git tree)
>>>>>>>>>>>
>>>>>>>>>>> 2) Run virt-install (0.400.3) with my existent image in img/img.winxp
>>>>>>>>>>>
>>>>>>>>>>> # virt-install --import -n winxp -f img/img.xp3 --vnc --hvm
>>>>>>>>>>> --accelerate --ram 800
>>>>>>>>>>>
>>>>>>>>>> That looks fine.
>>>>>>>>>>
>>>>>>>>>>> However, this step returns error like:
>>>>>>>>>>>
>>>>>>>>>>> "ERROR    Could not find usable default libvirt connection."
>>>>>>>>>>>
>>>>>>>>>> If 'virsh --connect qemu:///system' doesn't work, you probably didn't
>>>>>>>>>> configure your libvirt install correctly.
>>>>>>>>>>
>>>>>>>>> But it works! So the problem stays elsewhere.
>>>>>>>>>
>>>>>>>>> Do you have any suggestion?
>>>>>>>>>
>>>>>>>> Hmm, then you probably need this patch to virtinst, since our URI detection
>>>>>>>> likely isn't as thorough as libvirt:
>>>>>>>>
>>>>>>>> http://hg.et.redhat.com/cgi-bin/hg-virt.cgi/applications/virtinst--devel/rev/030fbc6df74f
>>>>>>>>
>>>>>>> I got the latest code from hg tree, and installed that.  But running
>>>>>>> "virt-install" (without option) returns the error message:
>>>>>>>
>>>>>>> Traceback (most recent call last):
>>>>>>>   File "/usr/local/bin/virt-install", line 36, in <module>
>>>>>>>     from virtinst.VirtualCharDevice import VirtualCharDevice
>>>>>>> ImportError: No module named VirtualCharDevice
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> How to fix this problem?
>>>>>>>
>>>>>> There must be an install issue, you shouldn't have this issue. My guess is
>>>>>> /usr/local/bin/virt-install isn't looking at the newly installed virtinst libs.
>>>>>>
>>>>>> What command did you use to install? What distro are you on? What does:
>>>>>>
>>>>>> python -c 'import virtinst; print virtinst'
>>>>>>
>>>>>> show? It should list the path to the newly installed virtinst, the one via
>>>>>> your distro.
>>>>> It prints out: <module 'virtinst' from 'virtinst/__init__.py'>""
>>>>>
>>>>> I checked again, and see that virt-install was installed into
>>>>> /usr/local/bin, which might not be the right place? It should be in
>>>>> /usr/bin, right? So how to install virt-install there?
>>>>>
>>>>> If that matters, I install virt-install by running "python setup.py
>>>>> install". I am on Ubuntu 904, and I heard that Python 2.6.2 on this
>>>>> distro has some problems with installation, so that they always put
>>>>> code into /usr/local/ (??)
>>>> I tried to install virt-install again, with command:
>>>>
>>>> python setup.py install --prefix=/usr
>>>>
>>>> Then I run "virt-install" again (without option). This time I got the
>>>> below error:
>>>>
>>>> Traceback (most recent call last):
>>>>  File "/usr/bin/virt-install", line 36, in <module>
>>>>    from virtinst.VirtualCharDevice import VirtualCharDevice
>>>> ImportError: No module named VirtualCharDevice
>>>>
>>>>
>>>> So it is still the same problem as before. Do you have any hint?
>>>>
>>>> My impression is that so far, libvirt stuff is not well supported in
>>>> Ubuntu, but only in Fedora Core.
>>> I had another attempt on another Ubuntu (8.04), and it seems to work
>>> this time. Ubuntu 804 use older Python 2.5.2, and that makes the
>>> difference?
>>>
>> Not sure exactly. Sounds like the newer Ubuntu version changed how python
>> packages are installed by default, and something is slipping up. The above
>> error message likely means that 'virt-install' couldn't find the newly
>> installed virtinst libs. Maybe a PYTHONPATH problem?
>>
>> Either way, if you find out how to install virtinst from source on the newer
>> ubuntu version, let us know.
>>
>>> However, when I run the below command to import an existent KVM image:
>>>
>>> virt-install --import -n xp3 -f img/img.xp3 --vnc --hvm --accelerate
>>> --ram 1000 --prompt
>>>
>>> I got the question: "How large would you like the disk img/img.xp3 to be?"
>>>
>>> This is really confused to me: it seems virt-install is trying to
>>> create a new image, while all i want to do is to *import* image (I
>>> already specified --import above), but not to create a new one.
>>>
>>> How to fix this?
>>>
>> I'm not sure, I can't reproduce on my system with a latest checkout. Does that
>> file path definitely exist? Can you attach the output of that command with the
>> --debug flag?
>>
> 
> It seems that the problem is because I didnt give the full path to the
> existent image above?
> 
> I tried again, this time give virt-install the full path to the image,
> and it seems to work now.
> 
> Is it better if virt-install can figure it out the full path, even if
> we specify the relative path?
> 

virt-install can already handle relative paths, and that is what I tested when
trying to reproduce your problem. I'm not sure what went wrong on your end.

>> Also, if you are importing an XP image, you will probably want to specify
>> --os-variant winxp to get the proper defaults.
>>
> 
> How does this help, and what virt-install does with --os-variant option here??
> 

It sets up things like ACPI, APIC, clock setting (windows needs 'localtime'),
desired disk and network models (like virtio if using recent linux).

- Cole