Bug 1035118

Step 3 is wrong, instead of

virsh dumpxml mig > mig.xml

you should use

virsh dumpxml --migratable mig > mig.xml

Do you get the same error when you get the XML correctly?

(In reply to Jiri Denemark from comment #1)
> Step 3 is wrong, instead of
> 
> virsh dumpxml mig > mig.xml
> 
> you should use
> 
> virsh dumpxml --migratable mig > mig.xml
> 
> Do you get the same error when you get the XML correctly?


After I use the above command:
virsh dumpxml --migratable mig > mig.xml

Then do migration,I will get another error message:

# virsh migrate --live mig qemu+ssh://$ip/system --xml mig.xml
error: unsupported configuration: Target controller type ide does not match source usb

The original steps should be okay to reproduce the problem.

Fixed upstream with:

commit be904e4eeb83cb5513af8dad01fdfbb924f87bb1
Author: Peter Krempa <pkrempa>
Date:   Thu Dec 5 18:33:01 2013 +0100

    conf: Fix XML formatting of RNG device info
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1035118
    
    When outputting the XML for the RNG device, the code didn't format the
    PCI address info. Additionally the schema wasn't expecting the info
    although it was being parsed and used internally. Fix those mistakes and
    add test for the PCI info section.

Tested the bug with:
libvirt-1.1.1-14.el7.x86_64

Steps:
Scenario A:test rng device with random mode.
1.1.Prepare a guest,add rng device in xml file or add it from virt-manager GUI.
2.Boot the guest.

3.Use virsh dumpxml to get the xml of the guest.
# virsh dumpxml mig > mig.xml
……
    <rng model='virtio'>
      <backend model='random'>/dev/random</backend>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </rng>
……
4.Migrate the guest use --xml option,it can be migrated successfully.
# virsh migrate --live mig qemu+ssh://$ip/system --xml mig.xml

5.Update the xml to change pci address,will get expected error as:
# virsh migrate --live mig qemu+ssh://$ip/system --xml mig.xml
error: unsupported configuration: Target device PCI address 0000:00:03.01 does not match source 0000:00:03.00


Scenario B:test rng device with egd mode.
1.Prepare a guest with rng device,mode:Entropy Gathering Daemon,type:tcp,source mode as connect.

2.On host,run the below command:
#cat /dev/urandom | nc -l localhost 708

3.Boot the guest and dump the xml file of the guest,it will show as:
    <rng model='virtio'>
      <backend model='egd' type='tcp'>
        <source mode='connect' host='localhost' service='708'/>
        <protocol type='raw'/>
      </backend>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
    </rng>

4.Change tcp to udp in xml as:
    <rng model='virtio'>
      <backend model='egd' type='udp'>
        <source mode='connect' host='localhost' service='708'/>
        <protocol type='raw'/>
      </backend>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
    </rng>

5.Migrate the guest with the updated xml file,it can be migrated successfully.
# virsh migrate --live mig qemu+ssh://$ip/system --xml mig.xml

6.Change backend model from 'egd' to 'random' in xml from step3:
    <rng model='virtio'>
      <backend model='random' type='tcp'>
        <source mode='connect' host='localhost' service='1024'/>
        <protocol type='raw'/>
      </backend>
      <alias name='rng0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </rng>

7.Migrate the guest with the updated xml file,it can be migrated successfully.
# virsh migrate --live mig qemu+ssh://$ip/system --xml mig.xml


Refer to the above comments:
Scenario A works well.
Scenario B:step 5 and step 7,stable guest ABI doesn't check backend mode and type of rng device.

So move the bug back to ASSIGNED.

Backend type, transport and source are not guest visible changes and thus don't change the ABI. They can and should be modifiable on migration thus are not checked in the ABI check.

(In reply to Peter Krempa from comment #7)
> Backend type, transport and source are not guest visible changes and thus
> don't change the ABI. They can and should be modifiable on migration thus
> are not checked in the ABI check.

Refer to the above comments and comment 6,move the bug to VERIFIED.

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.