Re: [vserver] Bind Mount into VServer fails due to permission problems

From: Herbert Poetzl <>
Date: Sat 14 Nov 2009 - 15:40:58 GMT
Message-ID: <>

On Fri, Nov 13, 2009 at 03:05:08PM +0100, Thomas Gebhardt wrote:
> Dear Herbert,

> > IMHO the chdir happens _before_ the --bind mount should
> > be affective, maybe you mounted it already there or
> > you have a problem with the barrier flag (note that
> > the debian 2.6.26 branch is broken and requires manual
> > fixes to all the attribute flags when switching to or
> > from such a kernel), besides that, I'd suggest to get
> > a more recent util-vserver snapshot ...

> ok, I changed linux-image- and
> util-vserver-basic-debian_0.30.216-pre2849 (which were advertised
> on this list recently), but that didn't change anything.

> > things which might work:

> > - you can do the bind mount before the the guest is
> > started (either permanently or via one of the
> > guest start scripts) and exclude the path from the
> > namespace cleanup

> > - you could put the actual nfs mount in the guest's
> > fstab.remote, as long as mounting itself can happen

> I tried these alternatives with "various" success: sometimes
> it worked, then suddenly it ceased to work. By sniffing the
> network traffic I noticed that the ip source address of the
> nfs requests changed from the vserver ip to the host ip
> some minutes after the vserver was started. This seems to be
> the reason for my permission problems.

> I also tried to mount the nfs share within the
> vserver manually (with SYS_ADMIN, SECURE_MOUNT, BINARY_MOUNT
> [b|c]capabilities enabled):

> mount -t nfs nfsserver:/home /home

> but the source ip address of the resulting nfs traffic was
> the host(!) address, not the vserver address.

> It might be worth to mention that the ip address of the vserver
> is bound to a vlan device while the host ip runs on native eth0.
> I can't see that this fact is of any influence for the flaw, however

okay, I guess we need more details about your setup,
specifically the nfs part (server, client, versions)
and of course, somebody to help with testing ....


> Thanks, Thomas
Received on Sat Nov 14 15:43:24 2009

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