[libvirt] [PATCH v3 00/12] Add user namespace support for libvirt lxc

[Richard Weinberger]

Am 11.06.2013 05:12, schrieb Gao feng:
> On 06/11/2013 04:51 AM, Richard Weinberger wrote:
>> Am 10.06.2013 21:53, schrieb Richard Weinberger:
>>> Am 10.06.2013 21:17, schrieb Richard Weinberger:
>>>> Hi!
>>>>
>>>> Am 04.06.2013 13:03, schrieb Daniel P. Berrange:
>>>>>> It's still under review. needs some ACK.
>>>>>> If you can help to test or ACK this patchset, it will be very helpful. :)
>>>>>>
>>>>>> Actually, I just want to ping...
>>>>>
>>>>> I've been away on holiday for 2 weeks, so not had a chance to review
>>>>> it yet. I'll get to it this week. I hope we'll get this in the 1.0.6
>>>>> release this month.
>>>>
>>>> Finally I've found some time to test version 4 of the userns patch set.
>>>> But I'm unable to create a container.
>>>>
>>>> ---cut---
>>>> linux:~ # LANG=C /opt/libvirt/bin/virsh -c lxc:/// create c1.conf
>>>> error: Failed to create domain from c1.conf
>>>> error: Interner Fehler guest failed to start: PATH=/bin:/sbin TERM=linux container=lxc-libvirt container_uuid=3f86c48b-b027-4838-ba17-6202a1d7398b
>>>> LIBVIRT_LXC_UUID=3f86c48b-b027-4838-ba17-6202a1d7398b LIBVIRT_LXC_NAME=c1 /bin/bash
>>>> error receiving signal from container: Input/output error
>>>> ---cut---
>>>>
>>>> lxcContainerWaitForContinue() in src/lxc/lxc_controller.c fails with EIO.
>>>> Maybe because the clone()'ed child dies and the file descriptor used for synchronization becomes invalid.
>>>>
>>>> Here my container config:
>>>> ---cut---
>>>> <domain type='lxc'>
>>>>     <name>c1</name>
>>>>     <memory>102400</memory>
>>>>     <os>
>>>>       <type>exe</type>
>>>>       <init>/bin/bash</init>
>>>>     </os>
>>>>     <idmap>
>>>>           <uid start='0' target='100000' count='100000'/>
>>>>           <gid start='0' target='100000' count='100000'/>
>>>>     </idmap>
>>>>     <devices>
>>>>       <console type='pty'/>
>>>>           <filesystem type='mount'>
>>>>             <source dir='/root/c1/rootfs'/>
>>>>             <target dir='/'/>
>>>>           </filesystem>
>>>>     </devices>
>>>> </domain>
>>>> ---cut---
>>>>
>>>> Any ideas how to debug this further?
>>>> This is Linux 3.9.0 with all namespaces enabled.
>>>
>>> Whoops, forgot to add the libvirtd debug output:
>>>
>>> ---cut---
>>> 2013-06-10 19:41:24.661+0000: 29211: debug : virCommandRunAsync:2241 : About to run
>>> PATH=/usr/lib64/mpi/gcc/openmpi/bin:/sbin:/usr/sbin:/usr/local/sbin:/root/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games LIBVIRT_DEBUG=1 LIBVIRT_LOG_OUTPUTS=1:stderr
>>> /opt/libvirt/lib/libvirt_lxc --name c1 --console 20 --security=none --handshake 23 --background
>>> 2013-06-10 19:41:24.663+0000: 29211: debug : virFileClose:90 : Closed fd 24
>>> 2013-06-10 19:41:24.663+0000: 29211: debug : virCommandRunAsync:2246 : Command result 0, with PID 29303
>>> 2013-06-10 19:41:24.664+0000: 29303: debug : virFileClose:90 : Closed fd 3
>>> 2013-06-10 19:41:24.665+0000: 29303: debug : virFileClose:90 : Closed fd 4
>>> 2013-06-10 19:41:24.666+0000: 29303: debug : virFileClose:90 : Closed fd 5
>>> 2013-06-10 19:41:24.666+0000: 29303: debug : virFileClose:90 : Closed fd 6
>>> 2013-06-10 19:41:24.667+0000: 29303: debug : virFileClose:90 : Closed fd 7
>>> 2013-06-10 19:41:24.667+0000: 29303: debug : virFileClose:90 : Closed fd 8
>>> 2013-06-10 19:41:24.668+0000: 29303: debug : virFileClose:90 : Closed fd 9
>>> 2013-06-10 19:41:24.668+0000: 29303: debug : virFileClose:90 : Closed fd 10
>>> 2013-06-10 19:41:24.668+0000: 29303: debug : virFileClose:90 : Closed fd 11
>>> 2013-06-10 19:41:24.668+0000: 29303: debug : virFileClose:90 : Closed fd 12
>>> 2013-06-10 19:41:24.668+0000: 29303: debug : virFileClose:90 : Closed fd 13
>>> 2013-06-10 19:41:24.669+0000: 29303: debug : virFileClose:90 : Closed fd 14
>>> 2013-06-10 19:41:24.669+0000: 29303: debug : virFileClose:90 : Closed fd 15
>>> 2013-06-10 19:41:24.670+0000: 29303: debug : virFileClose:90 : Closed fd 16
>>> 2013-06-10 19:41:24.670+0000: 29303: debug : virFileClose:90 : Closed fd 17
>>> 2013-06-10 19:41:24.670+0000: 29303: debug : virFileClose:90 : Closed fd 18
>>> 2013-06-10 19:41:24.671+0000: 29303: debug : virFileClose:90 : Closed fd 19
>>> 2013-06-10 19:41:24.671+0000: 29303: debug : virFileClose:90 : Closed fd 22
>>> 2013-06-10 19:41:24.790+0000: 29211: debug : virCommandRun:2115 : Result status 0, stdout: '(null)' stderr: '(null)'
>>> ---cut---
>>>
>>> Looks like libvirt_lxc was executed and died silently.
>>
>> Found the problem. /opt/libvirt/var/log/libvirt/lxc/c1.log contained the info I needed.
>> Search permissions for /root were missing. m(
>> Would be nice if virsh would be able to tell one this...
>>
>
> :)
> have fun with user namespace & libvirt.
> And thanks for your test.

Yeah. So far it looks very good.
I was able to convert my containers from my custom lxc/userns setup to libvirt+userns.

One more question, is it by design that virsh lxc-enter-namespace does not setup
uid/gid mappings?

Thanks,
//richard