[libvirt-users] [API reference] Are there XML-handling API to retrieve info directly from xml configure file

[Zhihua Che]

在 2012年4月11日 下午7:22，Richard W.M. Jones <rjones at redhat.com> 写道：
> On Wed, Apr 11, 2012 at 12:01:55PM +0100, Daniel P. Berrange wrote:
>> On Wed, Apr 11, 2012 at 06:41:34PM +0800, Zhihua Che wrote:
>> > BTW, Does libvirt supply any function which can return the process
>> > identifier of the domain?
>>
>> No, we don't consider the PID of the QEMU process to be part of the
>> public API, since that is a hypervisor specific implementation detail.
>> Why do you want to know that ?  Maybe there is some API you can use
>> to get do the same thing
>
> I agree with Dan that you're probably doing it for the wrong reasons
> and shouldn't need to know the PID.
>
> Nevertheless, it's pretty simple to map a running domain name to a
> qemu PID, by parsing the '-name' parameter from the process list.
> eg the following works for simple names (no spaces, metachars etc):
>
> $ sudo virsh list --all
>  Id Name                 State
> ----------------------------------
>  2 builder-rhel6        running
>
> $ ps ax | grep '[-]name builder-rhel6' | awk '{print $1}'
> 2311
>
> Rich.
>

Hi,

   I guess I miss another thing. I thought the domain xml config file
was stored in etc/libvirt/qemu/ directory.
   But I did a interesting experiment. I edited a xml config file
ubuntu-1.xml in the above directory. After defining the domain, I
removed the domain's xml config file and found
   that it could still be started by 'start ubuntu-1'. I guess the
action 'define' would parse the original config file and store it in
another 'safe' place. What's this place?
   I wish I could handle some emergence in case if I knew this place.