[PATCH 3/3] docs: kbase: Port 'debuglogs' document from libvirt's wiki

[Daniel P. Berrangé]

On Mon, Aug 03, 2020 at 11:53:20AM +0200, Peter Krempa wrote:
> On Mon, Aug 03, 2020 at 11:44:39 +0200, Kashyap Chamarthy wrote:
> > On Thu, Jul 30, 2020 at 12:30:32PM +0200, Peter Krempa wrote:
> > 
> > (Probably this needs to be done in a separate patch from this Wiki->rST
> > conversion, but a quick point inline.)
> 
> Yes.
> 
> > 
> > [...]
> > 
> > > +How to turn on debug logs for libvirt
> > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > +
> > > +Persistent setting
> > > +^^^^^^^^^^^^^^^^^^
> > 
> > [...]
> > 
> > > +
> > > +   # LEGACY SETTINGS PRIOR LIBVIRT 4.4.0 SEE BELOW! #
> > > +   log_level = 1
> > > +   log_filters="1:qemu 3:remote 4:event 3:util.json 3:rpc"
> > > +   log_outputs="1:file:/var/log/libvirt/libvirtd.log"
> > > +
> > > +::
> > > +
> > > +   # PREFERRED SETTINGS AFTER LIBVIRT 4.4.0 #
> > > +   log_filters="3:remote 4:event 3:util.json 3:rpc 1:*"
> > 
> > The above "PREFERRED" settings doesn't capture QMP commands, does it?
> > The '1:qemu' is supposed to do it.  
> 
> It has 1:* since after 4 it supports wildcats which is equivalent to
> 1:qemu.
> 
> > FWIW, after some debugging sessions with Dan Berrangé, I have been using
> > the following filters:
> > 
> >     "1:libvirt 1:qemu 1:conf 1:security 3:event 3:json 3:file 3:object 1:util"
> 
> Didn't you debug a 4.4.0 or older libvirt?

This syntax above works fine on any version. The doc you've proposed here
needed differnet syntax for pre-4.4.0 since it is attempting to enable
wildcards via log_debug=1 or 1:*

In OSP we never try todo that as it is almost always overkill. Instead
we tell users to just explicitly list each category that is considered
important and don't use the wildcards.


Regards,
Daniel
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