Re: [vserver] Problem with delete vserver with SYS_ADMIN set

From: Steve Kieu <msh.computing_at_gmail.com>
Date: Fri 26 Aug 2011 - 11:24:21 BST
Message-ID: <CAAQ-o+9HNqOqUEheMJaMs1kc0VODmz-aMz3qyo98Px_M4NeeWw@mail.gmail.com>

OK I tried to umount the volue, mkfs.ext3 on it, mount it again with option
tag removed. crate a test vserver with these MOUNT flags in ccapabilities
and strat it, stop and delete, got error. I ran strace rm -f a file inside
the vserver dir and capture its output attached.

No speacial erroe at dmesg and message at all. The error message when
running vserver delete is just thousand of lines like this

remove `/var/lib/vservers/test/sbin/udevadm': Read-only file system

I found that if I unmount the /var/lib/vservers and then mount it again, and
I am able to remove the directory. so do not need to reboot the whole server
to do that

cheers

On Thu, Aug 25, 2011 at 10:30 PM, Herbert Poetzl <herbert@13thfloor.at>wrote:

> On Thu, Aug 25, 2011 at 10:15:24PM +1000, Steve Kieu wrote:
>
> >> an what happens when you do not give those ccapabilities?
>
> > without these, it behaves normally - delete fine, no problem so
> > far. It only happens in sparc , not in x86 and x86_64.
>
> that would suggest that something inside the guest
> happens which requires those ccapabilities
>
> any idea what that could be on a 'normal' guest
> start?
>
> >> could you upload the entire log for that and keep the
> >> resulting filesystem for further investigation?
>
> > I will try tomorrow with ext3. Have migrated all vs into
> > another host so it can be free to experiment.
>
> > What log are you talking about? dmesg log or kernel.log.
>
> the log of your guest start/stop and the errors you
> get (basically a copy of the shell input/output)
> but of course, if you get some output in dmesg,
> please add that as well
>
> > Should I strace it when
> > I do a rm -rf /var/lib/vservers/NAME?
> > (after vserver NAME delete failed, I tried to manually
> > rm -rf it and same error.
>
> yes, please do so, from the information you provided
> so far, it sounds like something inside the guest is
> either modified or mounted (in some strange way) so
> this information could be quite helpful
>
> > I can work around this limitation after all we I hit the brick
> > wall - will sshfs mount from the host through vserver fstab
> > which will work fine I guess.It might even be better solution
> > in terms of security; vserver is still only virtualization for
> > sparc for now (lxc is still far more unstable in my test). so
> > it is good if this can be fixed.
>
> I'm pretty sure we can identify the issue and if it is
> actually Linux-VServer related we will fix it :)
>
> best,
> Herbert
>
> PS: if you have some time for interactive testing, you
> could pay a visit to the IRC channel and look for Bertl
>
> > Thanks,
>
> >> Repeat with mkfs.ext4 - still the same
>
> >> let's stick with ext3 for now, that's easier to debug :)
>
> > -- Steve Kieu
>

-- 
Steve Kieu

Received on Fri Aug 26 11:24:37 2011
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