Error during VM migration "Target domain net card does not match source"

Problem

When migrating a virtual machine (VM) from one cluster node to another, the following error may occur:

stderr: error: unsupported configuration: Target domain net card count 1 does not match source 2

This error indicates that the platform detects one network interface for the VM, but the VM's configuration on the cluster node actually contains two interfaces. This discrepancy prevents successful migration.

The issue occurs when a previously attached network interface was not properly detached from the VM. This can happen due to:

a failure during the interface detachment process;
an incomplete interface deletion operation.

As a result, the interface remains in the VM's configuration file but is absent from the VMmanager platform. This mismatch causes a configuration error during migration.

Solution

To resolve the issue, identify the network interface missing from the target VM in the platform and remove it:

Connect to the cluster node via SSH. For more information about connecting via SSH, see Workstation setup.
Identify the VM's internal name:
```
virsh list --all | grep <vm_name>
```
Example output
```
virsh list --all | grep testtest
460   5450_testtest    running
```
Comment
- testtest — the VM name;
- 5450_testtest — the VM's internal name.

Retrieve the list of the VM's interfaces:

virsh domiflist <internal_vm_name>

Comment

Example output

virsh domiflist 6_VM_import_from_Hyper-V
Interface    Type     Source    Model    MAC
------------------------------------------------------------
 vnet2       bridge   vmbr124   virtio   52:54:00:f0:fd:7b
 vnet3       bridge   vmbr116   virtio   52:54:00:f0:fd:07

Compare the list of MAC addresses from the command output with the virtual interfaces listed in the VMmanager platform:
1. Navigate to Virtual Machines → выберите ВМ → Parameters.
2. Open the Network Settings section → Virtual Interfaces block.
3. Identify which interface is present in the virsh domiflist output but missing from the platform list.
Remove the extra interface. Depending on the VM's state, run the appropriate command:
- for a running VM:
```
virsh detach-interface <internal_vm_name> <interface_type> --mac <mac_address> --live --persistent
```
  Comment
  - — name obtained in step 2;
  - — interface type from step 3 (e.g., bridge or ethernet);
  - — MAC address of the interface to remove;
  - --live — performs a live detachment (without stopping the VM);
  - --persistent — persists the change in the running VM's configuration.
  Example for a running VM
```
virsh detach-interface 5450_testtest bridge --mac 52:54:00:f0:fd:07 --live --persistent
```
- for a shut down VM:
```
virsh detach-interface <internal_vm_name> <interface_type> --mac <mac_address> --config
```
  Comment
  - — name obtained in step 2;
  - — interface type from step 3 (e.g., bridge or ethernet);
  - — MAC address of the interface to remove;
  - --config — persists the change in the VM's configuration file.
  Example for a shut down VM
```
virsh detach-interface 5450_testtest bridge --mac 52:54:00:f0:fd:07 --config
```

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