[libvirt-users] Get PID of a domain's QEMU instance from its domain ID

[Martin Kletzander]

On Tue, Mar 21, 2017 at 12:50:39PM +0100, Peter Krempa wrote:
>On Tue, Mar 21, 2017 at 12:06:25 +0100, Martin Kletzander wrote:
>> On Mon, Mar 20, 2017 at 02:11:21PM +0100, Thibaut SAUTEREAU wrote:
>> > Hello,
>> >
>> > I cannot find a way to retrieve PIDs of QEMU instances from libvirt domains'
>> > IDs (I'm using libvirt C API). I recognize it sounds like a bad idea doing so
>> > (and I know PIDs are explicitly made not available, as I gathered from the
>> > source code and on your IRC channel) but I need that to use the perf_event_open
>> > syscall in order to gather statistics on my QEMU/KVM guests. I also know
>> > libvirt now supports some perf events but only a few and I need more. I could
>> > submit patches to add them and I will definitely consider that but in the
>> > meantime...
>
>Looks like you are looking for:
>http://libvirt.org/formatdomain.html#elementsPerf
>
>and
>
>http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainGetPerfEvents
>
>> >
>> > What would be the best way to get those PIDs? I tried using the XML file but
>> > PID is hidden in there too. I took a look at QEMU Machine Protocol. Now I'm
>> > going to walk /proc and match on guests names but it is not that elegant.
>> > Any ideas?
>
>Just to re-iterate. We hide it because users should not fiddle with the
>VMs behind our backs.
>
>> >
>>
>> `ps aux | grep $UUID | grep -v grep` ??
>
>This will obviously work, but we won't give you an elegant way since we
>don't want you to know the pid.

I mentioned that since Thibaut knows about why we hide that, how to get
the current perf events as well as how to add new ones (at least
according to how I understood the message).
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: Digital signature
URL: <http://listman.redhat.com/archives/libvirt-users/attachments/20170321/3a73b5b1/attachment.sig>