libvirt users - Jan 2020 - Re: error: internal error: unable to execute QEMU command 'blockdev-mirror': Cannot find device= nor node_name=

On Fri, Jan 17, 2020 at 01:45:00 +0100, Oliver Dzombic
wrote:
> Hi,
> 
> i try to test live-migration using this command:
> 
> #virsh migrate --copy-storage-all --verbose --live kvm1776
> qemu+ssh://nodeb/system
> 
> 
> Instant error message:
> 
> error: internal error: unable to execute QEMU command
'blockdev-mirror':
> Cannot find device=drive-sata0-0-0 nor node_name=drive-sata0-0-0
Hi,

for completness I'm re-posting the reply I gave in the bug you filed at
https://bugzilla.redhat.com/show_bug.cgi?id=1792088.

The bug was caused by the switch to use blockdev. It was fixed in
libvirt-6.0 which was released yesterday with the following patchset:

commit f5259ba4027807e82ce040f63db40efe56e86925
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 18:50:46 2019 +0100

    qemu: migration: Properly setup mirror for blockdev configurations
    
    With blockdev we need to refer to the nodename of the disk source image
    as the source argument for the blockdev-mirror operation while still
    keeping the old job name. With blockdev we must also persist the job in
    qemu.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit 3e35156bd18badf9757cad0904493e7eda530320
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 18:44:22 2019 +0100

    qemu: migration: Mention disk target rather than the drive name in debug msg
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit 69abc80f5e58ba2c0f30e1d7296be8524631246d
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 17:47:46 2019 +0100

    qemu: migration: Split out setup of the migration target
    
    Separate out allocation of the virStorageSource corresponding to the
    target NBD export of the migration.
    
    As part of the splitout we allocate the export name explicitly as that
    one must not change regardless whether blockdev is used or not to
    provide compatibility.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit 0d0b490a32be5cb4f8a3b103784e1f10ce6c51ce
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 17:46:29 2019 +0100

    qemu: blockjob: Allow NULL 'mirror' for block copy jobs due to
migration
    
    The non-shared-storage migration tracks the storage source used
    explicitly in the migration data so we must allow for processing of the
    block job which has NULL mirror as the mirror will not be populated.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit e1910a1f3b5a1926bc130ddd16ebee0a3cf8db27
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 17:26:01 2019 +0100

    qemu: migration: Simplify cleanup in qemuMigrationSrcNBDCopyCancelOne
    
    Now that the cleanup section does not exist remove the label.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit 37e801340ac6902e63e83983f5e606fbc38a23e6
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 17:22:53 2019 +0100

    qemu: migration: Access job name from job struct
    
    qemuMigrationSrcNBDCopyCancelOne uses the block job data structure but
    generated it's own job name rather than taking it from the block job
    data.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit 5339f57a0bf958f5c432c6ae6b655bf234ea0971
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 17:02:33 2019 +0100

    qemu: migration: Properly export backend for NBD storage migration
    
    With -blockdev we must use the nodename as the export but we must keep
    the name of the export as it was before to ensure compatiblity.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>

commit 83137f5d3710ffe5a36ba9218ddc382d6675dc32
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Fri Dec 6 16:54:33 2019 +0100

    qemu: migration: Simplify handling of 'diskAlias' when adding NBD
exports
    
    Declare the variable inside the loop with automatic clearing.
    
    Signed-off-by: Peter Krempa <pkrempa@redhat.com>
    Reviewed-by: Eric Blake <eblake@redhat.com>