[libvirt] problem attaching/detaching disk

Mon Mar 7 05:28:12 UTC 2011

At 03/05/2011 05:35 AM, Shi Jin Write:
> Although the attach/detach problem has been solved, I fond the driver name
> issue still causes problems restoring from a saved VM with disk attached.

I can reproduce this a bug of libvirt: we can not restore the VM from the file
we saved.

Thank you for reporting this problem.
I will make a patch to fix it.

Thanks.
Wen Congyang

> 
> For example, once saved, the checkpoint file would contains
>  <disk type='file' device='disk'>
>       <driver name='file' type='qcow2'/>
>       <source
> file='/vrstorm/cloud/PrivateAccounts/74d37709b07be4bbae228dfc273e4339/volumes/vol-126'/>
>       <target dev='vdf' bus='virtio'/>
>       <alias name='virtio-disk5'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
> function='0x0'/>
>     </disk>
> 
> And then the restore would fail:
> 
> [cloudadmin at test2 images]$ virsh restore checkpoint
> error: Failed to restore domain from checkpoint
> error: internal error unsupported driver name 'file' for disk
> '/vrstorm/cloud/PrivateAccounts/74d37709b07be4bbae228dfc273e4339/volumes/vol-126'
> 
> 
> If I simply edit the checkpoint file to change file to qemu:<driver
> name='qemu' type='qcow2'/>
> 
> Then it works.
> 
> [cloudadmin at test2 images]$ virsh restore checkpoint
> Domain restored from checkpoint
> 
> 
> So there is indeed a problem with the driver name. Maybe I should
> start a new thread on it?
> 
> 
> Shi
> 
> 
> On Fri, Mar 4, 2011 at 11:44 AM, Shi Jin <jinzishuai at gmail.com> wrote:
> 
>> Finally, everything works for if I simply change my template to use the
>> /usr/libexec/qemu-kvm instead of /usr/bin/kvm, which is a symbolic link to
>> it.
>> Not sure why it matters but that does solve all the mysteries.
>>
>> Shi
>>
>> On Fri, Mar 4, 2011 at 9:56 AM, Shi Jin <jinzishuai at gmail.com> wrote:
>>
>>> It seems that your qemu does not support monitor command 'drive_add'.
>>>> What's version of your qemu?
>>>>
>>>> Thank you. Here is my version
>>> [cloudadmin at test2 ~]$ /usr/libexec/qemu-kvm -version
>>> QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2), Copyright (c)
>>> 2003-2008 Fabrice Bellard
>>>
>>> I finally think it is a permission issue. If I run commands as root and
>>> get kvm run by the default qemu user, both attach-disk and detach-disk works
>>> like your case.
>>>
>>> However, if I set to run as another user, such as cloudamin, attach-disk
>>> works but detach-disk does not.
>>> My libvirtd.conf has
>>> unix_sock_group = "cloudadmin"
>>> unix_sock_rw_perms = "0770"
>>> auth_unix_ro = "none"
>>> auth_unix_rw = "none"
>>> log_level = 3
>>> log_outputs="3:file:/var/log/libvirt/libvirtd.log"
>>>
>>> and qemu.conf has
>>> user = "cloudadmin"
>>> group = "cloudadmin"
>>> dynamic_ownership = 0
>>>
>>> All images are owned by the cloudadmin:cloudadmin.
>>>
>>> Is there a problem with this setup?
>>>
>>> Thank you very much.
>>> Shi
>>>
>>>>  > 15:31:52.902: debug : virEventRunOnce:595 : Poll got 1 event
>>>>
>>>>> 15:31:52.902: debug : virEventDispatchTimeouts:405 : Dispatch 3
>>>>> 15:31:52.902: debug : qemuMonitorAddDevice:1878 : mon=0x7f3628341370
>>>>>
>>>> device=virtio-blk-pci,bus=pci.0,addr=0x6,drive=drive-virtio-disk1,id=virtio-disk1
>>>>
>>>> When 'drive_add' failes, we do not call qemuMonitorAddDevice(). But it is
>>>> called.
>>>>
>>>>> 15:31:52.902: debug : virEventDispatchHandles:450 : Dispatch 8
>>>>> 15:31:52.902: debug : qemuMonitorCommandWithHandler:230 : Send command
>>>>> 'device_add
>>>>>
>>>> virtio-blk-pci,bus=pci.0,addr=0x6,drive=drive-virtio-disk1,id=virtio-disk1'
>>>>> for write with FD -1
>>>>
>>>> What's the reply of command 'device_add'? Can you provide it. I think it
>>>> should fail.
>>>>
>>>> Thanks.
>>>> Wen Congyang
>>>>
>>>>>
>>>>> Than you very much.
>>>>>
>>>>> Shi
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Mar 3, 2011 at 10:12 PM, Wen Congyang <wency at cn.fujitsu.com>
>>>> wrote:
>>>>>
>>>>>> At 03/04/2011 01:00 PM, Shi Jin Write:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>     <disk type='file' device='disk'>
>>>>>>>>       <driver name='qemu' type='qcow2' cache='none'/>
>>>>>>>>      <source file='/var/lib/libvirt/images/rhel6rc_64.img'/>
>>>>>>>>      <target dev='hda' bus='ide'/>
>>>>>>>>      <alias name='ide0-0-0'/>
>>>>>>>>      <address type='drive' controller='0' bus='0' unit='0'/>
>>>>>>>>    </disk>
>>>>>>>>    <disk type='file' device='cdrom'>
>>>>>>>>      <driver name='qemu' type='raw'/>
>>>>>>>>      <source file='/var/lib/libvirt/images/test.iso'/>
>>>>>>>>      <target dev='hdc' bus='ide'/>
>>>>>>>>      <readonly/>
>>>>>>>>      <alias name='ide0-1-0'/>
>>>>>>>>      <address type='drive' controller='0' bus='1' unit='0'/>
>>>>>>>>    </disk>
>>>>>>>>     <disk type='file' device='disk'>
>>>>>>>>      <driver name='file' type='qcow2'/>
>>>>>>>>       <source file='/var/lib/libvirt/images/test3.img'/>
>>>>>>>>       <target dev='vdb' bus='virtio'/>
>>>>>>>>       <alias name='virtio-disk1'/>
>>>>>>>>      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>>>>>>>> function='0x0'/>
>>>>>>>>    </disk>
>>>>>>>>    <controller type='ide' index='0'>
>>>>>>>>      <alias name='ide0'/>
>>>>>>>>      <address type='pci' domain='0x0000' bus='0x00' slot='0x01'
>>>>>>>> function='0x1'/>
>>>>>>>>    </controller>
>>>>>>>>
>>>>>>>>
>>>>>>>> Thank you very much. It is exactly the same output as mine,
>>>> particularly
>>>>>>>  <driver name='file' type='qcow2'/>
>>>>>>> I thought it has to be name='qemu' to detach properly but since you
>>>>>> didn't
>>>>>>> have a problem, I am very lost on why mine didn't work.
>>>>>>>
>>>>>>> My libvirtd.log shows (with debugging turned on)
>>>>>>> 14:43:18.965: debug : qemuMonitorCommandWithHandler:235 : Receive
>>>> command
>>>>>>> reply ret=0 errno=0 33 bytes 'Device 'virtio-disk1' not found^M
>>>>>>> '
>>>>>>> 14:43:18.965: debug : virEventDispatchTimeouts:405 : Dispatch 3
>>>>>>> 14:43:18.965: debug : virEventDispatchHandles:450 : Dispatch 8
>>>>>>> 14:43:18.965: error : qemuMonitorTextDelDevice:2314 : operation
>>>> failed:
>>>>>>> detaching virtio-disk1 device failed: Device 'virtio-disk1' not
>>>> found^M
>>>>>>>
>>>>>>> Do you know what the "device not found" error means?
>>>>>>
>>>>>> It seems attaching virtio-disk1 failed.
>>>>>> Can you provide the log when you attach virtio-disk1?
>>>>>>
>>>>>> Thanks.
>>>>>> Wen Congyang
>>>>>>
>>>>>>>
>>>>>>> Thanks.
>>>>>>>
>>>>>>> Shi
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Shi Jin, Ph.D.
>>>
>>>
>>
>>
>> --
>> Shi Jin, Ph.D.
>>
>>
> 
> 