[lxc-users] Creating a container as non root

[Cal Leeming [Simplicity Media Ltd]]

It's also worth mentioning that fakeroot/fakechroot have some nasty issues
with debootstrap;
https://bugs.launchpad.net/ubuntu/+source/fakechroot/+bug/1265857

One theory I'm exploring is building "base images" on a machine that does
have root, by running debootstrap on every flavor/arch then using
mksquashfs to compress it down into an image. You could then use unsquashfs
to force whatever uid/gid you wanted, then fakechroot/fakeroot to make
whatever changes you need to the container before launching. The downside
is that there is no public mirror that offers this at the moment (other
than the latest 13.x ubuntu, which contains a filesystem.squashfs you can
extract, but it's 700mb). You could create your own set of base images,
then wrap scripts around them to create the templates, but this is
absolutely not going to work out of the box, there is a lot of tedious work
involved.

I'm planning on doing a better write up about this (as its something I'm
actively working on), will update this thread at a later date.

Hope this helps a bit

Cal




On Thu, Jan 9, 2014 at 3:39 PM, Michael H. Warfield <mhw at wittsend.com>wrote:

> On Thu, 2014-01-09 at 08:08 +0200, Kevin Wilson wrote:
> > Hello,
> > I believe that creating a container as non root user should be
> straight-forward.
>
> Sigh...  I'm afraid not...
>
> Funny, Serge and I just had a couple of comments in exchange about this
> very thing with regards to templates.  He's been working on getting
> containers to run under unprivileged users and I know the Fedora and
> CentOS templates will not even run under a non-user (they check).  His
> remark was that most templates will not and can not, including the
> Ubuntu template.  Problem with the Ubuntu template (and, presumably the
> Debian template) is the use of debboot which, in turn, uses mknod to
> create devices for the container - and you're then toast.
>
> The problem there is that there are going to be privileged operations
> (chown, mknod, etc) that are simply going to require privileges in the
> host which are not available to the non-priv user.
>
> I'm not so sure about the busybox template but I wouldn't be optimistic.
> It does look like it checks to see if it's in a user namespace and uses
> mknod if not and does something else if it is.  So, it looks like it
> SHOULD work.  But you have to have user namespaces set up to work.
>
> Once a container is created, it should be possible to run it under a
> non-priv user if you have a recent enough kernel along with the latest
> lxc tools.  But it seems likely we could ever navigate the morass of
> creating a template using lxc-create as a non-priv user.
>
> > I added a user named "test" and I am trying to create a container (see
> > below the sequence). I am running latest lxc git
> > (built from source, as root)  on Fedora 20.
>
> > useradd test
> > su test
> >
> > lxc-create -t busybox -n busyboxTest
> > I get:
> >
> > You lack access to /home/test/.local/share/lxc/
> > I ran;
> > mkdir -p /home/test/.local/share/lxc/
> >
> > Then again:
> > lxc-create -t busybox -n busyboxTest
> > lxc-create: Permission denied - failed to create directory
> '/run/user/0/lock/'
> >
> > failed to create lock
> > System error loading container
> >
> > What should I do ?
> >
> > Regards,
> > Kevin
>
> Regards,
> Mike
> --
> Michael H. Warfield (AI4NB) | (770) 978-7061 |  mhw at WittsEnd.com
>    /\/\|=mhw=|\/\/          | (678) 463-0932 |
> http://www.wittsend.com/mhw/
>    NIC whois: MHW9          | An optimist believes we live in the best of
> all
>  PGP Key: 0x674627FF        | possible worlds.  A pessimist is sure of it!
>
>
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