[libvirt] problem attaching/detaching disk

Shi Jin jinzishuai at gmail.com
Fri Mar 4 21:35:33 UTC 2011 

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.

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.
>
>


-- 
Shi Jin, Ph.D.
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