[Libcg-devel] [libvirt]: Not able to login to container when cgroup is enabled

[Daniel P. Berrange]

On Wed, Oct 07, 2009 at 08:12:02PM +0530, Dhaval Giani wrote:
> On Wed, Oct 07, 2009 at 06:57:48AM -0700, Dan Smith wrote:
> > R> can you help me here ?
> > 
> > Probably not, I'm not familiar with cgconfig nor the latest cgroup
> > support in libvirt.
> > 
> > R> 14:47:24.556: warning : qemudStartup:565 : Unable to create cgroup
> > R> for driver: No such device or address
> > 
> > My guess is that this means you don't have the cgroup filesystem
> > mounted, or it's mounted in a way that prevents libvirt from doing its
> > work.  IIRC, there are things you can do to the system that require a
> > reboot to undo.  If cgconfig is setting up the cgroups in such a way,
> > you might need to reboot between stopping cgconfig and trying libvirt
> > by itself.
> > 
> 
> Or the cgroups are being setup in funny fashion. Rishi, what does your
> config file look like?
> 
> > R> But when i start cgconfig service, then i am not able to open
> > R> console for my container.
> > 
> > Again, knowing nothing of cgconfig, I can only speculate that it's
> > doing something to prevent accessing the console pty.
> > 
> 
> cgconfig does nothing apart from setup the cgroup filesystem as
> mentioned in the configuration files.
> 
> > I would push on the libcgroup folks to help figure out what it's doing
> > (either by default or with your config) to prevent that and then go
> > from there.
> > 
> 
> Would appreciate any help from the libvirt folks who have worked on the
> cgroup support in libvirt.

The most likely suspect is that the cgroups controllers were mounted or
unmounted after libvirtd started. A restart of libvirtd ought to resolve
the problem if this is indeed the case

Daniel;
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