[libvirt] [Xen-devel] [PATCH] libxl: support domainReset

Ian Campbell Ian.Campbell at citrix.com
Tue Aug 5 18:45:48 UTC 2014


On Tue, 2014-08-05 at 17:12 +0100, Wei Liu wrote:
> On Tue, Aug 05, 2014 at 04:30:47PM +0100, Ian Campbell wrote:
> > On Tue, 2014-08-05 at 09:10 -0600, Jim Fehlig wrote:
> > > Ian Campbell wrote:
> > > > On Tue, 2014-08-05 at 08:06 -0600, Jim Fehlig wrote:
> > > >   
> > > >> Ian Campbell wrote:
> > > >>     
> > > >>> On Tue, 2014-08-05 at 10:55 +0200, Olaf Hering wrote:
> > > >>>   
> > > >>>       
> > > >>>> The original report was that 'Reset' does not work from GUI, like
> > > >>>> virt-manager or virsh. I think the expected outcome is like pushing the
> > > >>>> reset button on a physical board. Xen doesnt do it that way, no idea
> > > >>>> about others.
> > > >>>>     
> > > >>>>         
> > > >>> Sounds like you want libxl_domain_reboot then, perhaps with a fallback
> > > >>> on ERROR_NOPARAVIRT for an HVM guest to sending a trigger.
> > > >>>   
> > > >>>       
> > > >> Hrm, I don't think that's right .  It should be a hard reset
> > > >>
> > > >> http://libvirt.org/html/libvirt-libvirt.html#virDomainReset
> > > >>
> > > >> destroy/start seems the correct way to implement this.
> > > >>     
> > > >
> > > > Yes, given that requirement it is. Sorry for the noise.
> > > >
> > > > Would some sort of hard reset API be useful in libxl?
> > > >   
> > > 
> > > Sure.  I think having an API that emulates a power reset button would be
> > > a nice addition to libxl's domain operations.  The destroy/start
> > > approach incurs a small bit of overhead, which would be avoided with
> > > such an API.  Clients (perhaps incorrectly) implementing their own
> > > notion of reset  would also be avoided.
> > 
> > I think this ought to become pretty easy once Wei's patches to record
> > the guest cfg in libxl are completed. Wei -- what do you think?
> > 
> 
> I don't think this "reset" API will need to record any state, i.e. this
> feature looks unrelated to my work. What do I miss?

It's a forced reboot, so the API would need to destroy and then recreate
the domain. Recreate would need to use the state your patches arrange
for libxl to store.

Ian.




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