On Wed, Nov 11, 2015 at 04:57:59PM +0100, Marek Marczykowski-Górecki wrote:
> On Tue, Sep 15, 2015 at 11:21:00AM -0600, Jim Fehlig wrote:
> > Daniel P. Berrange wrote:
> > > On Tue, Sep 15, 2015 at 10:57:50AM -0600, Jim Fehlig wrote:
> > >
> > >> Daniel P. Berrange wrote:
> > >>
> > >>> On Tue, Sep 15, 2015 at 09:26:23AM -0600, Jim Fehlig wrote:
> > >>>
> > >>>
> > >>>> Instead of a hardcoded DEBUG log level, use the overall
> > >>>> daemon log level specified in libvirtd.conf when opening
> > >>>> a log stream with libxl. libxl is very verbose when DEBUG
> > >>>> log level is set, resulting in huge log files that can
> > >>>> potentially fill a disk. Control of libxl verbosity should
> > >>>> be placed in the administrator's hands.
> > >>>>
> > >>>> Signed-off-by: Jim Fehlig <jfehlig@xxxxxxxx>
> > >>>> ---
> > >>>> src/libxl/libxl_conf.c | 18 +++++++++++++++++-
> > >>>> 1 file changed, 17 insertions(+), 1 deletion(-)
> > >>>>
> > >>>>
> > >>> ACK, this makes sense as default behaviour. As a future enhancement
> > >>> you might also consider supporting a config setting in /etc/libvirt/libxl.conf
> > >>> to explicitly control the libxl library logging behaviour independantly.
> > >>>
> > >>>
> > >> I had actually thought of adding it there first, but then took this
> > >> approach assuming it would be more receptive upstream :-). Personally,
> > >> I'm on the fence. I like the idea of a single knob to control log level
> > >> throughout the daemon, making it a bit easier on admins. On the other
> > >> hand, individual knobs are more friendly to those pouring through logs.
> > >> I can add a knob in libxl.conf if preferred.
> > >>
> > >
> > > After thinking about it some more, I could actually see value in
> > > create a dedicated virLogSource() instance, solely for libxl
> > > library messages. If we then created a virLogSourceGetPriority()
> > > method, you could query that to see if to turn on logging for
> > > the libxl library. That would ultimately allow you to turn on
> > > debug for just the libxl library if desired, eg
> > >
> > > static virLogSource virLogLibXL = {
> > > .name = "libxl.libxl_library",
> > > ....
> > > }
> > >
> > > LIBVIRT_LOG_FILTERS="1:libxl_library"
> > >
> >
> > Ah, good idea. I'll look into it.
>
> Is it done anywhere? If not, how can I help?
>
> This the above change (setting libxl log level to libvirtd global one),
> makes almost impossible to get libxl debug, because the rest of libvirtd
> trashes the logs (hundreds virEvent* and virObject* messages, at
> "info"(!) level).
Presumably that's because you are using LIBVIRT_DEBUG=1 or setting
log_debug=1 in /etc/libvirt/libvirtd.log. That is generally discouraged
because it turns on all logging, which is essentially unusably verbose.
It is also better to use more specific log settings, eg when I debug
the QEMU driver I usually use
log_filters="1:qemu 1:security 3:event 3:object 1:util"
log_outputs="1:file:/var/log/libvirt/libvirtd.log"
This generates log messages from every source file in qemu and
security directories, and also log messages from every file
in the util/ directory *except* for event & object files.
So it is much more managable to read.
The log filter strings just do a wildcard match against the
VIR_LOG_INIT("...."); lines in each source file, so you can
make things more or less specific as you desire.
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list