Re: [libvirt] [Qemu-devel] Re: Libvirt debug API

[Jes Sorensen]

On 04/22/10 20:47, Anthony Liguori wrote:
> On 04/12/2010 07:23 AM, Jamie Lokier wrote:
>> Some simple but versatile hook ideas:
>>
>>     -<emulator-append-option>   (no space splitting, one option,
>> appended)
>>     -<emulator-append-options>  (space splitting multiple options)
>>     -<emulator-prepend-option>
>>     -<emulator-prepend-options>
>>     -<emulator-setenv name="NAME">VALUE</emulator-setenv>
> 
> I'd strongly suggest not focusing on manipulating command line
> arguments.  I think in the not too distant future, few people will pass
> command line arguments as opposed to just using configuration files.
> 
> We are very close to being able to cover 90% of current users via the
> config file.

There will always be a place for adding command line parameters for
debugging purposes. When you try to debug a problem, the first port of
call is to look at the command line arguments libvirt uses to launch
qemu and replicate those with addons. It's a nightmare today and you end
up losing networking and other things. Having an optional debug options
thing that one can set quickly from virt-manager would make it so much
easier to retry different settings fast while replicating the setup that
is normally run.

Having to manually edit xml files for making changes is just not a
viable solution.

Speaking of which, one problem with the current XML format is that it
relies on hard-coding the path to QEMU. Instead if should rely on the
system default and provide an optional tag for debugging purposes. That
would make it easier to migrate specifications from one OS to another,
without manually having to edit the QEMU tag.

Cheers,
Jes