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@test2 ~]$ /usr/libexec/qemu-kvm -version

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@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
>>>
>>
>>
>
>