libvirt users - Jul 2013 - Hotplug of disk devices in LXC failed with libvirt of version 1.0.2

Hi Daniel,

I noticed that the patch "Add support for hotplug/unplug of disk devices in
LXC" you wrote had been merged into libvirt of version 1.0.2.
But when I used this function, it report an error with details as following:

ubuntu@lxc:~$ vir attach-device instance-0000002c disk.xml --config          
error: Failed to attach device from disk.xml
error: Unable to create device /proc/18377/root/dev/sdb: Permission denied

ubuntu@lxc:~$ vir attach-device instance-0000002c disk.xml
error: Failed to attach device from disk.xml
error: Unable to create device /proc/18377/root/dev/sdb: Permission denied

ubuntu@lxc:~$ cat disk.xml
    <disk type='block' device='disk'>
      <driver type='raw' cache='none'/>
      <source dev='/dev/dm-0'/>
      <target dev='sdb' bus='scsi'/>
    </disk>

ubuntu@lxc:~$ ll /dev/dm-0
brw-rw---- 1 root disk 252, 0 Jul 15 03:39 /dev/dm-0

ubuntu@lxc:~$ dpkg -l|grep libvirt
ii  libvirt-bin                      1.0.2-0ubuntu11                           
programs for the libvirt library
ii  libvirt0                         1.0.2-0ubuntu11                           
library for interfacing with different virtualization systems
ii  python-libvirt                   1.0.2-0ubuntu11                           
libvirt Python bindings
 				
And in this lxc vm, through dmesg the following information can be seen:
ubuntu@lxc2:~$ dmesg
[433287.227288] type=1400 audit(1373874475.861:55): apparmor="DENIED"
operation="mknod" info="Failed name lookup" error=-13
parent=1 profile="/usr/sbin/libvirtd" name="dev/sdb"
pid=1541 comm="libvirtd" requested_mask="c"
denied_mask="c" fsuid=0 ouid=0

What's the real problem and How can I fix it.  I really appreciate your
help.
Thanks!
--------------
Best regards!
GuanQiang
2013-07-15

On 07/15/2013 04:01 PM, hzguanqiang wrote:
> Hi Daniel,
> 
> I noticed that the patch "Add support for hotplug/unplug of disk
devices in LXC" you wrote had been merged into libvirt of version 1.0.2.
> But when I used this function, it report an error with details as
following:
> 
> ubuntu@lxc:~$ vir attach-device instance-0000002c disk.xml --config
> error: Failed to attach device from disk.xml
> error: Unable to create device /proc/18377/root/dev/sdb: Permission denied
> 
> ubuntu@lxc:~$ vir attach-device instance-0000002c disk.xml
> error: Failed to attach device from disk.xml
> error: Unable to create device /proc/18377/root/dev/sdb: Permission denied
> 
> ubuntu@lxc:~$ cat disk.xml
>     <disk type='block' device='disk'>
>       <driver type='raw' cache='none'/>
>       <source dev='/dev/dm-0'/>
>       <target dev='sdb' bus='scsi'/>
>     </disk>
> 
You should use attach-disk not attach-device.

vir attach-disk instance-0000002c /dev/dm-0 sdb

Thanks

Hi, Gao Feng

I've tried what you said, but still exists the problem:

ubuntu@lxc:~$ vir attach-disk instance-0000002c   /dev/dm-0 sdb
error: Failed to attach disk
error: Unable to create device /proc/10366/root/dev/sdb: Permission denied

I think finding what it means by saying 'Unable to create device
/proc/10366/root/dev/sdb: Permission denied' is the key.
But anyway, thanks for your help!
>On 07/15/2013 04:01 PM, hzguanqiang wrote:
>> Hi Daniel,
>> 
>> I noticed that the patch "Add support for hotplug/unplug of disk
devices in LXC" you wrote had been merged into libvirt of version 1.0.2.
>> But when I used this function, it report an error with details as
following:
>> 
>> ubuntu@lxc:~$ vir attach-device instance-0000002c disk.xml --config
>> error: Failed to attach device from disk.xml
>> error: Unable to create device /proc/18377/root/dev/sdb: Permission
denied
>> 
>> ubuntu@lxc:~$ vir attach-device instance-0000002c disk.xml
>> error: Failed to attach device from disk.xml
>> error: Unable to create device /proc/18377/root/dev/sdb: Permission
denied
>> 
>> ubuntu@lxc:~$ cat disk.xml
>>     <disk type='block' device='disk'>
>>       <driver type='raw' cache='none'/>
>>       <source dev='/dev/dm-0'/>
>>       <target dev='sdb' bus='scsi'/>
>>     </disk>
>> 
>
>You should use attach-disk not attach-device.
>
>vir attach-disk instance-0000002c /dev/dm-0 sdb