[lxc-users] [Unable to start using lvm backend]

[Serge Hallyn]

Yes, unprivileged users cannot manipulate the lvm devices on the host.

You can still use user namespaces though.  I have a few containers on my main
server which do that.  They each run in a unique uid range, but are started by
root, so that they can use lvm (actually luks-encrypted lvm) backends.

Just add the lxc.id_map lines as per usual to containers which are owned by
root.  And make sure to allocate the ranges to root in /etc/sub[ug]id.

-serge

Quoting Andrea Masi (eraclitux at gmail.com):
> The problem seems related to unprivileged containers that seems cannot work
> with -B lvm.
> Must we assume that lvm backed store (and maybe others) actually cannot
> work with unprivileged containers?
> 
> 
> 2015-01-23 17:02 GMT+01:00 Andrea Masi <eraclitux at gmail.com>:
> 
> > Hi,
> > I'm using lxc 1.0.6 on ubuntu 14.04.
> > I've no problems creating/running on dir backing store but when I use lvm
> > I cannot start containers getting these errors:
> >
> > lxc-start 1422026234.562 ERROR    bdev - failed to determine fs type for
> > '/dev/lxc/lvm-cont'
> > lxc-start 1422026234.563 ERROR    lxc_conf - failed to determine fs type
> > for '/dev/dm-0'
> > lxc-start 1422026234.564 ERROR    lxc_conf - failed to mount rootfs
> > lxc-start 1422026234.564 ERROR    lxc_conf - failed to setup rootfs for
> > 'lvm-cont'
> > lxc-start 1422026234.565 ERROR    lxc_conf - Error setting up rootfs mount
> > after spawn
> > lxc-start 1422026234.565 ERROR    lxc_start - failed to setup the container
> > lxc-start 1422026234.566 ERROR    lxc_sync - invalid sequence number 1.
> > expected 2
> > lxc-start 1422026234.566 ERROR    lxc_start - failed to spawn 'lvm-cont'
> > lxc-start 1422026234.574 ERROR    lxc_start_ui - The container failed to
> > start.
> > lxc-start 1422026234.575 ERROR    lxc_start_ui - Additional information
> > can be obtained by setting the --logfile and --logpriority options.
> >
> > I've tried different template createds with -t download for example:
> > lxc-create -t download -n lvm-cont -B lvm -- -d ubuntu -r utopic -a amd64
> >
> > I can manually mount with no problem /dev/lxc/lvm-cont
> >
> > Any idea on what can it be wrong?
> >
> > Thanks.
> >
> > --
> > www.eraclitux.com
> >
> 
> 
> 
> -- 
> www.eraclitux.com

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