brainstorming for UDS-N - Cloud Infrastructure

Stéphane Graber stgraber at
Wed Sep 29 15:55:11 BST 2010

On Wed, 2010-09-29 at 09:25 -0500, Jamie Strandboge wrote:
> On Tue, 2010-09-28 at 20:05 -0400, Stéphane Graber wrote:
> > On Tue, 2010-09-28 at 21:59 +0200, Allison Randal wrote:
> > > Server topics are included in all the other tracks, but the UDS team
> > > called out cloud technology for special attention. It's an area where
> > > Ubuntu is one of the leading players in driving innovation, which means
> > > it's a big opportunity for us as a community to make a difference in the
> > > world at large. This includes being a good guest and being a good host,
> > > as well as evaluating new technologies.
> > > 
> > > What's high on your list for this area?
> > > Allison
> > 
> > I guess an important topic when thinking of server is virtualization and
> > contextualization both for flexibility and security.
> > 
> > I believe we can greatly improve our VM server solution (my biggest wish
> > at the moment is for some kind of ACLs on VMs running in libvirt) and
> > prepare to have a rocking solution for the next LTS.
> > 
> When using qemu/kvm, libvirt can use the AppArmor security driver to
> confine VMs to only the files they need. This provides guest isolation
> and userspace host protection. This is on by default in Ubuntu's libvirt
> since Karmic and is also upstream.

I agree that libvirt itself can't do any scary changes on the system
when using apparmor. What I was more thinking about is the case where
you have a shared virtualization server with multiple users running VMs.

Something that's seen in other VM infrastructure is that ability to let
users create VM and manage them while still preventing them from
accessing/altering anyone else's VM running on that same host.

> > Contextualization is also something I use everyday as the current policy
> > at my employer is to have a full container per service. That means that
> > I currently administer a few hundreds VZ containers just for our
> > internal infrastructure (a few thousands if including customers).
> > 
> > Containers offer a lot of flexibility at a very low cost and can be used
> > to greatly improve everyone's security even on the desktop.
> > That's really something I believe we should focus more on and I know
> > there's an existing interest from both the Server and Security team.
> > We also have the chance to have Daniel Lezcano (upstream for LXC) at UDS
> > this time.
> AIUI, containers as currently implemented in the vanilla kernel should
> not be considered secure at this point (at least for root). There are
> apparently rather large patchsets that the different container upstreams
> use to address these issues. I'm not up on all the details though, but
> they can surely be googled.

Yes, currently my biggest issue with LXC (as it's in the upstream
kernel) is the lack of filtering of /proc.
Anyone can basically access /proc/sysrq-trigger or anything in /sys
giving hardware access in some cases.

OpenVZ doesn't have that issue as both /proc and /sys are filtered so
only the bare minimal is available blocking a container root user from
being able to do anything on the host.

That's mostly why we are still staying on 8.04 here as it's the only
Ubuntu release with an update OpenVZ kernel. We'll consider switching to
LXC once these missing "features" are implemented.

Anyway, the current kernel container implementation is still a lot
better than using any regular chroot and I'm pretty sure that LXC
upstream is willing to address these remaining issues to see containers
being used more and more both on the server and the desktop.

Stéphane Graber
Ubuntu developer
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