[libvirt] libvirt-libxl driver defaulting to tap disk and not working (ubuntu 12.10 + xen 4.5 + libvirt 1.2.3 + openstack)

[Tian, Shuangtai]

Jim and Stefan

Thanks , I will check my environment again.

-----Original Message-----
From: Stefan Bader [mailto:stefan.bader at canonical.com] 
Sent: Tuesday, April 22, 2014 4:20 PM
To: Jim Fehlig; Tian, Shuangtai
Cc: libvir-list at redhat.com
Subject: Re: [libvirt] libvirt-libxl driver defaulting to tap disk and not working (ubuntu 12.10 + xen 4.5 + libvirt 1.2.3 + openstack)

On 21.04.2014 23:53, Jim Fehlig wrote:
> Tian, Shuangtai wrote:
>> Hi, Jim
>> The blktap seems not a module in xen 4.5, when I tried the load it , can not find the module, is there something wrong I did?
>>   
> 
> It would be provided by your dom0 kernel, not Xen.  The Ubuntu Xen 
> kernel doesn't provide a blktap module?

There is a blktap source package which can be installed separately. Though I must admit I never tried to use it. There is some code for blktap(2) in the Xen source but I had to disable that because it would otherwise clash with the external package.
Tian, you may try to "sudo apt-get install blktap-utils" which should pull in the other pieces (libraryies/dkms module).

-Stefan

> 
> Regards,
> Jim
> 
>> BTW ,I compiled the xen4.5 by myself.
>> Thanks ! 
>>
>> -----Original Message-----
>> From: Jim Fehlig [mailto:jfehlig at suse.com]
>> Sent: Friday, April 18, 2014 11:52 PM
>> To: Tian, Shuangtai
>> Cc: libvir-list at redhat.com
>> Subject: Re: [libvirt] libvirt-libxl driver defaulting to tap disk 
>> and not working (ubuntu 12.10 + xen 4.5 + libvirt 1.2.3 + openstack)
>>
>> Tian, Shuangtai wrote:
>>   
>>> HI
>>>
>>> I am an openstacker, when I used the latest libvirt and xen code to 
>>> run the openstack. Can not create the vm.
>>>
>>> there is an error in libxl log, you can see the log:
>>>
>>> Os : Ubuntu 12.10
>>>
>>>  
>>>
>>> Compiled against library: libvirt 1.2.3
>>>
>>> Using library: libvirt 1.2.3
>>>
>>> Using API: Xen 1.2.3
>>>
>>> Running hypervisor: Xen 4.5.0
>>>
>>>  
>>>
>>> libxl: debug: libxl_create.c:1356:do_domain_create: ao 0x7f7894002810:
>>> create: how=(nil) callback=(nil) poller=0x7f7894001bb0
>>>
>>> libxl: debug: libxl_device.c:251:libxl__device_disk_set_backend: 
>>> Disk vdev=xvda spec.backend=tap
>>>
>>> libxl: debug: libxl_device.c:210:disk_try_backend: Disk vdev=xvda, 
>>> backend tap unsuitable because blktap not available
>>>
>>>     
>>
>> In addition to John's suggestions, try loading a blktap module in dom0. 
>> It should work if a blktap driver is available.
>>
>> Regards,
>> Jim
>>
>>   
>>> libxl: error: libxl_device.c:289:libxl__device_disk_set_backend: no 
>>> suitable backend for disk xvda
>>>
>>> libxl: debug: libxl_event.c:1739:libxl__ao_complete: ao
>>> 0x7f7894002810: complete, rc=-3
>>>
>>> libxl: debug: libxl_create.c:1370:do_domain_create: ao 0x7f7894002810:
>>> inprogress: poller=0x7f7894001bb0, flags=ic
>>>
>>> libxl: debug: libxl_event.c:1711:libxl__ao__destroy: ao
>>> 0x7f7894002810: destroy
>>>
>>>  
>>>
>>> The blktap does work, and I also find the same error someone has 
>>> posted, 
>>> (http://www.redhat.com/archives/libvir-list/2013-February/msg01124.h
>>> tm
>>> l)
>>>
>>> When I change the type to “phy”, it also doesnot work. And try to 
>>> change the type to other options, also does not work.
>>>
>>> Can someone give me some suggestions?
>>>
>>> Thanks !
>>>
>>>  
>>>
>>> The XML from the openstack is :
>>>
>>> <domain type="xen">
>>>
>>>   <uuid>9e9ed86c-8892-40da-acd1-31ec6303abfe</uuid>
>>>
>>>   <name>instance-00000001</name>
>>>
>>>   <memory>524288</memory>
>>>
>>>   <vcpu>1</vcpu>
>>>
>>>   <os>
>>>
>>>     <type>xen</type>
>>>
>>>    
>>> <kernel>/opt/stack/data/nova/instances/9e9ed86c-8892-40da-acd1-31ec6
>>> 30
>>> 3abfe/kernel</kernel>
>>>
>>>    
>>> <initrd>/opt/stack/data/nova/instances/9e9ed86c-8892-40da-acd1-31ec6
>>> 30
>>> 3abfe/ramdisk</initrd>
>>>
>>>     <cmdline>ro root=/dev/xvda</cmdline>
>>>
>>>   </os>
>>>
>>>   <features>
>>>
>>>    <acpi/>
>>>
>>>     <apic/>
>>>
>>>   </features>
>>>
>>>   <clock offset="utc"/>
>>>
>>>   <devices>
>>>
>>>     <disk type="file" device="disk">
>>>
>>>       <driver name="tap2" type="raw" cache="none"/>
>>>
>>>       <source
>>> file="/opt/stack/data/nova/instances/9e9ed86c-8892-40da-acd1-31ec630
>>> 3a
>>> bfe/disk"/>
>>>
>>>       <target bus="xen" dev="xvda"/>
>>>
>>>     </disk>
>>>
>>>     <disk type="file" device="cdrom">
>>>
>>>       <driver name="tap2" type="raw" cache="none"/>
>>>
>>>       <source
>>> file="/opt/stack/data/nova/instances/9e9ed86c-8892-40da-acd1-31ec630
>>> 3a
>>> bfe/disk.config"/>
>>>
>>>       <target bus="ide" dev="xvdd"/>
>>>
>>>     </disk>
>>>
>>>     <interface type="bridge">
>>>
>>>       <mac address="fa:16:3e:d8:c3:c0"/>
>>>
>>>       <source bridge="br100"/>
>>>
>>>       <filterref
>>> filter="nova-instance-instance-00000001-fa163ed8c3c0"/>
>>>
>>>     </interface>
>>>
>>>     <console type="pty"/>
>>>
>>>     <graphics type="vnc" autoport="yes" keymap="en-us"
>>> listen="127.0.0.1"/>
>>>
>>>     <video>
>>>
>>>       <model type="xen"/>
>>>
>>>     </video>
>>>
>>>   </devices>
>>>
>>> </domain>
>>>
>>>  
>>>
>>>  
>>>
>>>  
>>>
>>> Best regards,
>>>
>>> Tian, Shuangtai
>>>
>>>  
>>>
>>> --------------------------------------------------------------------
>>> --
>>> --
>>>
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>>> libvir-list at redhat.com
>>> https://www.redhat.com/mailman/listinfo/libvir-list
>>>     
> 
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