On 08/24/22 17:55, Richard W.M. Jones wrote:
> On Wed, Aug 24, 2022 at 05:25:50PM +0200, Laszlo Ersek wrote:
>> On 08/24/22 16:13, Richard W.M. Jones wrote:
>>> On Wed, Aug 24, 2022 at 04:12:04PM +0200, Laszlo Ersek wrote:
>>>> I've started looking into RHBZ 1590721 for virt-p2v.
>>>>
>>>> For p2v development, quick local testing is helpful. "make
>>>> run-virt-p2v-directly" seems to be working great; however, the VM-based
>>>> test methods seem to have developed problems, since I last looked.
>>>>
>>>> Namely:
>>>>
>>>> - "make run-virt-p2v-in-a-vm" boots quickly, but the GUI does not come up.
>>>>
>>>> - "make run-virt-p2v-in-an-nvme-vm" boots *incredibly slowly*. I
>>>> checked, and the host CPU utilization during guest boot was around 20%
>>>> (and KVM was enabled). I don't understand how or why, but exposing the
>>>> "physical machine" disk over NVMe slows guest boot to a crawl -- it
>>>> looks strangely "IO-bound". I don't recall this from the time I added
>>>> this Makefile target!
>>>>
>>>> Do these symptoms look familiar?
>>>
>>> Yes I had noticed this. I did look at it briefly but couldn't work
>>> out what was going wrong.
>>
>> Thanks for confirming!
>>
>> I think I've found something, at least in relation to the first issue
>> (i.e., run-virt-p2v-in-a-vm booting quickly, but not launching the p2v
>> service). The problem seems to be the following:
>>
>> - Both the "physical machine" disk (fedora.img) and the bootable p2v
>> disk (virt-p2v.img) are based on Fedora 35. The former because of commit
>> 3b59d4acb82f ("Use fedora-35 as the test physical machine", 2022-05-10),
>> the latter because my host system runs Fedora 35, and so
>> virt-p2v-make-disk picks F35.
>>
>> - Consequently, both the "hd0" drive and the "usb0" drive are based on
>> the same Fedora 35 virt-builder template.
>>
>> - The grub command line (part of *both* images) specifies the *same*
>> kernel parameter "root=UUID=fae2...".
>>
>> - This filesystem UUID exists *twice* in the virtual machine however,
>> once in "hd0" and another time in "usb0" -- duplicate UUID.
>>
>> - The guest kernel ends up mounting / loading the root filesystem from
>> "hd0", that is, the "physical machine" Fedora 35 image, which does not
>> have anything injected that's related to p2v.
>
> Ah yes, I remember being extremely confused by why it was booting the
> wrong guest, and also I remember this exact bug having happened long
> ago in the past. Can we re-randomize the file system UUID of one of
> them when creating the test disks?
I'd like to implement it in a separate script.
Do I have to list that script under EXTRA_DIST?
What other Makefile macros?
Thanks!
Laszlo
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