[CCLM] Failed to migrate the VM with hotplug disk

CNV 4.19

Always

1. Create a source VM with hotplug disk on cluster1
2. Create a target VM (blank disk) with hotplug disk on cluster2
3. Create source VMIM and target VMIM to trigger the cross cluster live migration 

Target VMIM failed. 
$ oc get vmim
NAME          PHASE    VMI
vmim-target   Failed   vm-fedora-datavolume

describe the vmim
Events:
  Type     Reason            Age    From                       Message
  ----     ------            ----   ----                       -------
  Normal   SuccessfulCreate  6m35s  virtualmachine-controller  Created migration target pod virt-launcher-vm-fedora-datavolume-jwfj4
  Warning  FailedMigration   21s    virtualmachine-controller  Migration failed because target pod shutdown during migration


target virt-launcher pod
    State:      Terminated
      Reason:   Error
      Message:  07-09T13:15:33.582000Z"}
{"component":"virt-launcher","level":"info","msg":"hostname: vm-fedora-datavolume","subcomponent":"libvirt","thread":"40","timestamp":"2025-07-09T13:15:33.582000Z"}
{"component":"virt-launcher","level":"error","msg":"internal error: Unable to get session bus connection: Cannot spawn a message bus without a machine-id: Unable to load /var/lib/dbus/machine-id or /etc/machine-id: Failed to open file "/var/lib/dbus/machine-id": No such file or directory","pos":"virGDBusGetSessionBus:126","subcomponent":"libvirt","thread":"40","timestamp":"2025-07-09T13:15:33.582000Z"}
{"component":"virt-launcher","level":"error","msg":"internal error: Unable to get system bus connection: Could not connect: No such file or directory","pos":"virGDBusGetSystemBus:99","subcomponent":"libvirt","thread":"40","timestamp":"2025-07-09T13:15:33.582000Z"}
{"component":"virt-launcher","level":"info","msg":"Connected to libvirt daemon","pos":"libvirt.go:646","timestamp":"2025-07-09T13:15:33.841858Z"}
{"component":"virt-launcher","level":"info","msg":"Registered libvirt event notify callback","pos":"client.go:596","timestamp":"2025-07-09T13:15:33.844633Z"}
{"component":"virt-launcher","level":"info","msg":"Marked as ready","pos":"virt-launcher.go:77","timestamp":"2025-07-09T13:15:33.844778Z"}
panic: timed out waiting for domain to be defined
{"component":"virt-launcher-monitor","level":"info","msg":"Reaped Launcher main pid","pos":"virt-launcher-monitor.go:128","timestamp":"2025-07-09T13:21:22.850656Z"}
{"component":"virt-launcher-monitor","level":"info","msg":"Reaped pid 8 with status 512","pos":"virt-launcher-monitor.go:131","timestamp":"2025-07-09T13:21:22.850795Z"}
{"component":"virt-launcher-monitor","level":"error","msg":"dirty virt-launcher shutdown: exit-code 2","pos":"virt-launcher-monitor.go:145","timestamp":"2025-07-09T13:21:22.850811Z"}
{"component":"virt-launcher-monitor","level":"info","msg":"virt-launcher-monitor: Exiting...","pos":"virt-launcher-monitor.go:91","timestamp":"2025-07-09T13:21:30.660127Z"}


source vmim keeps in scheduling
$ oc get vmim -w
NAME          PHASE        VMI
vmim-source   Scheduling   vm-fedora-datavolume

migration succeeded

received vm yaml attached. 

we can not hotplug disk by "virtctl addvolume" for a receive vm, since the vm is not a normal running vm, but we can define the hotplug disk in the yaml as attachment. 
$ oc get vmi
NAME                   AGE   PHASE            IP    NODENAME   READY
vm-fedora-datavolume   66s   WaitingForSync                    False
$ virtctl addvolume vm-fedora-datavolume  --volume-name=blank-dv --serial=1234567890 --persist
Successfully submitted add volume request to VM vm-fedora-datavolume for volume blank-dv
$ virtctl removevolume vm-fedora-datavolume  --volume-name=blank-dv
error removing volume, Operation cannot be fulfilled on virtualmachineinstance.kubevirt.io "vm-fedora-datavolume": VMI is not running