openstack team mailing list archive

["Daniel P. Berrange" <berrange@xxxxxxxxxx>]

On Tue, Dec 06, 2011 at 12:04:53PM -0800, Dong-In David Kang wrote:
> 
> 
> ----- Original Message -----
> > On Mon, Dec 05, 2011 at 09:07:06PM -0500, Lorin Hochstein wrote:
> > >
> > >
> > > On Dec 4, 2011, at 7:46 AM, Soren Hansen wrote:
> > >
> > > > 2011/12/4 Lorin Hochstein <lorin@xxxxxxx>:
> > > >> Some of the LXC-related issues we've run into:
> > > >>
> > > >> - The CPU affinity issue on LXC you mention. Running LXC with
> > > >> OpenStack, you
> > > >> don't get proper "space sharing" out of the box, each instance
> > > >> actually sees
> > > >> all of the available CPUs. It's possible to restrict this, but
> > > >> that
> > > >> functionality doesn't seem to be exposed through libvirt, so it
> > > >> would have
> > > >> to be implemented in nova.
> > 
> > I recently added support for CPU affinity to the libvirt LXC driver.
> > It will
> > be in libvirt 0.9.8. I also wired up various other cgroups tunables
> > including
> > NUMA memory binding, block I/O tuning and CPU quota/period caps.
> 
>   Great news! 
>  We are also looking forward to seeing SElinux 'sVirt' support for
> LXC by libvirt.
> When do you think it will be available? 
> In libvirt-0.9.8?

0.9.8 is due out any day now, so not that. My goal is to get it
done by the Fedora 17 development freeze, so hopefully 0.9.9,
or 0.9.10 worst case.

>  By volume attachment, yes, we mean passing through host block devices that is dynamically created by 
> nova-volume service (using iscsi).
> 
> 
> > > > Why not address these couple of issues in libvirt itself?
> > 
> > If you let me know what issues you have with libvirt + LXC in
> > OpenStack,
> > I'll put them on my todo list.
> > 
> 
>  As Lorin said we implemented it using lxc-attach. 
> With lxc-attach we could pass the major/minor number of the (dynamically crated) devices to the LXC instance.
> And with lxc-attach we could do "mknod" inside of the LXC instance.
> I think supporting that by libvirt would be very useful.
> However, it needs lxc-attach working for the Linux kernel. 
> We had to upgrade and patch Linux kernel for that purpose.
> If there is a better way, it would be wonderful.
> But I don't know if there is a way other than using lxc-attach.

Yeah, I don't see any practical way todo hotplug with LXC without
having the kernel support merged for attaching to all types of
namespace. Once that's available it will be simple todo it via
libvirt

Regards,
Daniel
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