Open Stack

Hi,

So I was the developer who added support for LXC support initially, I
have some comments in line

 On Tue, 6 Dec 2011 12:04:53 -0800 (PST)
Dong-In David Kang <dkang at isi.edu> 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 at isi.edu>:
> > > >> 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.
>

We are running libvirt 0.9.7 in Ubuntu for Pangolin  and I expect to
have 0.9.8 before Pangolin is released.

>   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?
> 
> > 
> > > >> - LXC doesn't currently support volume attachment through
> > > >> libvirt. We were
> > > >> able to implement a workaround by invoking "lxc-attach" inside
> > > >> of OpenStack
> > > >> instead (e.g., see
> > > >> <https://github.com/usc-isi/nova/blob/hpc-testing/nova/virt/libvirt/connection.py#L482>.
> > > >> But to be able to use lxc-attach, we had to upgrade the Linux
> > > >> kernel in
> > > >> RHEL6.1 from 2.6.32 to 2.6.38. This kernel isn't supported by
> > > >> SGI, which
> > > >> means that we aren't able to load the SGI numa-related kernel
> > > >> modules.
> > 
> > Can you clarify what you mean by volume attachment ?
> > 
> > Are you talking about passing through host block devices, or hotplug
> > of
> > further filesystems for the container ?
> > 
> 
>  We tried both libvirt-0.9.3 and libvirt-0.9.7.
> For both versions, attachvolume called by OpenStack failed when the
> target instance is an LXC instance. In
> nova/virt/libvirt/connection.py, virt_dom.attachDevice(xml) failed
> for an LXC instance. virt_dom.attachDevice(xml) is calling libvirt
> API.
> 
>  By volume attachment, yes, we mean passing through host block
> devices that is dynamically created by nova-volume service (using
> iscsi).
> 

This is on my todo list for essex. 

> > > > 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.
> 
>  Thanks,
> 
>  David.
> 
> 
> > Regards,
> > Daniel
> > --
> > |: http://berrange.com -o-
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> 
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