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

[Xavier Gendre]

Hi Serge,

please, can you give more details about your settings of root owned 
unprivileged container with LVM backend? Indeed, I encounter the same 
problem as Andrea. I have tried to set the container as you explain but 
it fails to run...

root # grep lxc.id_map /var/lib/lxc/test/config
lxc.id_map = u 0 558752 65536
lxc.id_map = g 0 558752 65536

root # grep root /etc/sub[ug]id
/etc/subgid:root:558752:65536
/etc/subuid:root:558752:65536

root # lxc-start -n test
lxc-start: failed to determine fs type for '/dev/Pool/test'
lxc-start: failed to determine fs type for '/dev/dm-7'
lxc-start: failed to mount rootfs
lxc-start: failed to setup rootfs for 'test'
lxc-start: Error setting up rootfs mount after spawn
lxc-start: failed to setup the container
lxc-start: invalid sequence number 1. expected 2
lxc-start: failed to spawn 'test'
lxc-start: The container failed to start.
lxc-start: Additional information can be obtained by setting the 
--logfile and --logpriority options.

I use the download template with a Debian Wheezy 64 for this container.

Thanks,
Xavier

Le 25/01/2015 01:11, Serge Hallyn a écrit :
> 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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