feat(network): bind live migration to a dedicated SystemNetwork

[loktev-d]

Description

Adds:

• liveMigration.systemNetworkName ModuleConfig field. When set, VM live-migration traffic is routed over the per-node interfaces of a SystemNetwork CR from the SDN instead of the default node network.
• migrationiface controller resolves the per-node kernel interface name and writes it onto each Node as the annotation virtualization.deckhouse.io/migration-iface. virt-handler reads that annotation at startup and binds its migration proxy to the SystemNetwork's per-node IP.
• ModuleConfig validator to check if SystemNetwork added to liveMigration.systemNetworkName exists.
• New reason for VMOP if migration network is unavailable on nodes.

Why do we need it, and what problem does it solve?

Live-migration traffic competes with workload traffic on the default node network so we need to give ability to dedicate a separate VLAN to it.

What is the expected result?

Prerequisites: sdn module enabled with a configured SystemNetwork.

Steps:

1. Create or identify a SystemNetwork providing IPs on every VM node
2. Set the field on the virtualization ModuleConfig:

   kubectl patch mc virtualization --type=merge \
     -p '{"spec":{"settings":{"liveMigration":{"systemNetworkName":"migration"}}}}'
   

3. Wait for Node annotations virtualization.deckhouse.io/migration-iface
4. Trigger a live migration of any VM
5. Confirm:

   kubectl get internalvirtualizationvirtualmachineinstance -n <ns> <vm> -o jsonpath='{.status.migrationState.targetNodeAddress}'
   # Expect: an IP from the SystemNetwork pool, NOT the node's primary IP.
   

Negative paths:

• liveMigration.systemNetworkName unset -> VMOP fails.
• featuregates.SDN disabled -> controller does not register.
• sdn CRDs missing -> unstructured watches log a one-line warning and the reconciler treats every Node as "no annotation needed".

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: network
type: feature
summary: bind live migration to a dedicated SystemNetwork