net, tests, stuntime: Add L2 bridge client migration stuntime scenario (#4867)

##### Short description:
Implement stuntime scenario over Linux bridge in which the client VM
migrates off the server node.

##### More details:

##### What this PR does / why we need it:
Establish a performance baseline and enable regression detection for
Linux bridge live migration connectivity gaps (stuntime), mirroring the
existing OVN localnet coverage.

##### Which issue(s) this PR fixes:

##### Special notes for reviewer:
- The first commit is dedicated to the extraction of the shared stuntime
lib, and the consequent import changes needed in the localnet stuntime
sub-package.
- For now, the global stuntime threshold is set to a 5s placeholder.
Once we finish automating the remaining scenarios and have the baseline
data to calibrate our expectations, we’ll replace this with a more
precise, data-driven value.
- measure_stuntime() is also introduced in PR #4833. Whichever merges
first takes precedence — the other will rebase and remove the duplicate.

##### jira-ticket:
https://redhat.atlassian.net/browse/CNV-84398


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Tests**
* Added end-to-end L2 bridge migration tests with reusable server/client
VM fixtures, IPv4/IPv6 parametrization, and an active ping-based
stuntime measurement; updated a migration test to use the new fixtures
and disabled several variants pending validation.

* **Chores**
* Consolidated stuntime measurement into a shared helper used across
test suites.
* VM provisioning now supports optional template metadata labels and
related import cleanup.

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Author: rnetser

tests/network/l2_bridge/libl2bridge.py

@@ -12,7 +12,7 @@
 from libs.net.ip import random_ipv4_address
 from libs.net.vmspec import lookup_iface_status, lookup_iface_status_ip, wait_for_missing_iface_status
 from libs.vm.factory import base_vmspec, fedora_vm
-from libs.vm.spec import Affinity, CloudInitNoCloud, Interface, Multus, Network
+from libs.vm.spec import Affinity, CloudInitNoCloud, Interface, Metadata, Multus, Network
 from libs.vm.vm import BaseVirtualMachine, add_volume_disk, cloudinitdisk_storage
 from tests.network.libs import cloudinit
 from tests.network.libs.cloudinit import primary_iface_cloud_init
@@ -383,6 +383,7 @@ def secondary_network_vm(
     secondary_iface_name: str,
     secondary_iface_addresses: list[str],
     affinity: Affinity | None = None,
+    labels: dict[str, str] | None = None,
 ) -> BaseVirtualMachine:
     """Create a Fedora VM with a masquerade primary interface and a secondary Linux bridge interface.
 
@@ -394,6 +395,7 @@ def secondary_network_vm(
         secondary_iface_name: Name of the secondary network interface in the VM spec.
         secondary_iface_addresses: CIDR addresses to assign to the secondary interface via cloud-init.
         affinity: Optional node or pod affinity rules for scheduling.
+        labels: Optional labels to apply to the VM template metadata for pod scheduling.
     """
     spec = base_vmspec()
     spec.template.spec.domain.devices.interfaces = [  # type: ignore
@@ -407,6 +409,11 @@ def secondary_network_vm(
     if affinity:
         spec.template.spec.affinity = affinity
 
+    if labels:
+        spec.template.metadata = spec.template.metadata or Metadata()
+        spec.template.metadata.labels = spec.template.metadata.labels or {}
+        spec.template.metadata.labels.update(labels)
+
     ethernets = {}
     primary = primary_iface_cloud_init()
     if primary:

tests/network/l2_bridge/migration_stuntime/conftest.py

@@ -0,0 +1,110 @@
+from collections.abc import Generator
+from typing import Final
+
+import pytest
+from kubernetes.dynamic import DynamicClient
+from ocp_resources.namespace import Namespace
+
+import tests.network.libs.nodenetworkconfigurationpolicy as libnncp
+from libs.net import netattachdef as libnad
+from libs.net.ip import random_ipv4_address, random_ipv6_address
+from libs.net.vmspec import lookup_iface_status_ip
+from libs.vm.affinity import new_pod_affinity
+from libs.vm.vm import BaseVirtualMachine
+from tests.network.l2_bridge.libl2bridge import secondary_network_vm
+from tests.network.libs.stuntime import SERVER_VM_LABEL, ContinuousPing
+
+STUNTIME_BRIDGE_IFACE_NAME: Final[str] = "stuntime-bridge"
+
+
+@pytest.fixture(scope="module")
+def l2_bridge_stuntime_nad(
+    admin_client: DynamicClient,
+    namespace: Namespace,
+    bridge_nncp: libnncp.NodeNetworkConfigurationPolicy,
+) -> Generator[libnad.NetworkAttachmentDefinition]:
+    nad_name = "l2-bridge-nad"
+    config = libnad.NetConfig(
+        name=nad_name,
+        plugins=[libnad.CNIPluginBridgeConfig(bridge=bridge_nncp.desired_state_spec.interfaces[0].name)],  # type: ignore[index]
+    )
+    with libnad.NetworkAttachmentDefinition(
+        name=nad_name,
+        namespace=namespace.name,
+        config=config,
+        client=admin_client,
+    ) as nad:
+        yield nad
+
+
+@pytest.fixture(scope="class")
+def stuntime_server_vm(
+    unprivileged_client: DynamicClient,
+    namespace: Namespace,
+    l2_bridge_ip_family: int,
+    l2_bridge_stuntime_nad: libnad.NetworkAttachmentDefinition,
+) -> Generator[BaseVirtualMachine]:
+    with secondary_network_vm(
+        namespace=namespace.name,
+        name="l2bridge-stuntime-server",
+        client=unprivileged_client,
+        nad_name=l2_bridge_stuntime_nad.name,
+        secondary_iface_name=STUNTIME_BRIDGE_IFACE_NAME,
+        secondary_iface_addresses=[
+            f"{random_ipv4_address(net_seed=0, host_address=1)}/24",
+            f"{random_ipv6_address(net_seed=0, host_address=1)}/64",
+        ],
+        labels=dict([SERVER_VM_LABEL]),
+    ) as server_vm:
+        server_vm.start(wait=True)
+        server_vm.wait_for_agent_connected()
+        yield server_vm
+
+
+@pytest.fixture(scope="class")
+def stuntime_client_vm(
+    unprivileged_client: DynamicClient,
+    namespace: Namespace,
+    l2_bridge_stuntime_nad: libnad.NetworkAttachmentDefinition,
+    stuntime_server_vm: BaseVirtualMachine,
+) -> Generator[BaseVirtualMachine]:
+    with secondary_network_vm(
+        namespace=namespace.name,
+        name="l2bridge-stuntime-client",
+        client=unprivileged_client,
+        nad_name=l2_bridge_stuntime_nad.name,
+        secondary_iface_name=STUNTIME_BRIDGE_IFACE_NAME,
+        secondary_iface_addresses=[
+            f"{random_ipv4_address(net_seed=0, host_address=2)}/24",
+            f"{random_ipv6_address(net_seed=0, host_address=2)}/64",
+        ],
+        affinity=new_pod_affinity(label=SERVER_VM_LABEL),
+    ) as client_vm:
+        client_vm.start(wait=True)
+        client_vm.wait_for_agent_connected()
+        yield client_vm
+
+
+@pytest.fixture(scope="class")
+def l2_bridge_ip_family(request: pytest.FixtureRequest) -> int:
+    """IP family for stuntime measurement, activated by per-test parametrize."""
+    return request.param
+
+
+@pytest.fixture()
+def l2_bridge_active_ping(
+    l2_bridge_ip_family: int,
+    stuntime_server_vm: BaseVirtualMachine,
+    stuntime_client_vm: BaseVirtualMachine,
+) -> Generator[ContinuousPing]:
+    """Continuous ping session from client to server for stuntime measurement."""
+    server_ip = str(
+        lookup_iface_status_ip(
+            vm=stuntime_server_vm,
+            iface_name=STUNTIME_BRIDGE_IFACE_NAME,
+            ip_family=l2_bridge_ip_family,
+        )
+    )
+
+    with ContinuousPing(source_vm=stuntime_client_vm, destination_ip=server_ip) as ping:
+        yield ping

tests/network/l2_bridge/migration_stuntime/test_migration_stuntime.py

@@ -6,25 +6,27 @@
 Stuntime is defined as the connectivity gap from last successful reply before loss
 to first successful reply after recovery.
 
-Stuntime is measured using ICMP ping from client to server in 0.1s intervals, using ping -D so each
-log line includes a timestamp for gap calculation.
-The under-test VMs are configured on a Linux bridge secondary network, with a single interface,
+Stuntime is measured using ICMP ping from client to server in 0.1s intervals.
+The under-test VMs are configured with a secondary Linux bridge interface,
 on which IPv4/IPv6 static addresses will be defined according to the environment the test runs on.
 
 Client - The connectivity initiator VM that runs continuous ping toward the server VM.
 Server - The connectivity listener VM that receives the ping and responds.
 
-STP Reference:
-https://github.com/RedHatQE/openshift-virtualization-tests-design-docs/blob/main/stps/sig-network/stuntime_measurement.md
+STP: https://github.com/RedHatQE/openshift-virtualization-tests-design-docs/blob/main/stps/sig-network/stuntime_measurement.md
 """
 
 import pytest
 
-__test__ = False
+from libs.vm.affinity import new_pod_anti_affinity
+from tests.network.libs.stuntime import SERVER_VM_LABEL, STUNTIME_THRESHOLD_SECONDS, measure_stuntime
+from utilities.virt import migrate_vm_and_verify
+
+pytestmark = [pytest.mark.tier3]
 
 """
 Parametrize:
-    - ip_family:
+    - l2_bridge_ip_family:
         - ipv4 [Markers: ipv4]
         - ipv6 [Markers: ipv6]
 
@@ -36,9 +38,19 @@
 
 
 @pytest.mark.incremental
+@pytest.mark.parametrize(
+    "l2_bridge_ip_family",
+    [
+        pytest.param(4, marks=pytest.mark.ipv4, id="ipv4"),
+        pytest.param(6, marks=pytest.mark.ipv6, id="ipv6"),
+    ],
+    indirect=True,
+)
 class TestMigrationStuntime:
     @pytest.mark.polarion("CNV-15252")
-    def test_client_migrates_off_server_node(self):
+    def test_client_migrates_off_server_node(
+        self, admin_client, l2_bridge_ip_family, stuntime_client_vm, l2_bridge_active_ping
+    ):
         """
         Test that measured stuntime does not exceed the global threshold when the client
         VM migrates from the node hosting the server VM into a different node.
@@ -58,6 +70,12 @@ def test_client_migrates_off_server_node(self):
         Expected:
             - Measured stuntime does not exceed the global threshold.
         """
+        stuntime_client_vm.set_template_affinity(affinity=new_pod_anti_affinity(label=SERVER_VM_LABEL))
+        migrate_vm_and_verify(vm=stuntime_client_vm, client=admin_client)
+        measured_stuntime = measure_stuntime(active_ping=l2_bridge_active_ping)
+        assert measured_stuntime <= STUNTIME_THRESHOLD_SECONDS, (
+            f"Stuntime {measured_stuntime}s exceeds threshold ({STUNTIME_THRESHOLD_SECONDS}s)"
+        )
 
     @pytest.mark.polarion("CNV-15253")
     def test_client_migrates_between_non_server_nodes(self):
@@ -168,3 +186,9 @@ def test_server_migrates_to_client_node(self):
         Expected:
             - Measured stuntime does not exceed the global threshold.
         """
+
+    test_client_migrates_between_non_server_nodes.__test__ = False
+    test_client_migrates_to_server_node.__test__ = False
+    test_server_migrates_off_client_node.__test__ = False
+    test_server_migrates_between_non_client_nodes.__test__ = False
+    test_server_migrates_to_client_node.__test__ = False

…calnet/migration_stuntime/libstuntime.py tests/network/libs/stuntime.pytests/network/localnet/migration_stuntime/libstuntime.py renamed to tests/network/libs/stuntime.py tests/network/localnet/migration_stuntime/libstuntime.py renamed to tests/network/libs/stuntime.py

@@ -1,4 +1,4 @@
-"""Helpers for OVN localnet migration stuntime tests."""
+"""Helpers for migration stuntime tests."""
 
 import ipaddress
 import logging
@@ -23,35 +23,6 @@ class InsufficientStuntimeDataError(ValueError):
     """Raised when ping log has too few successful replies to compute stuntime."""
 
 
-def measure_stuntime(active_ping: "ContinuousPing") -> float:
-    """Stop the continuous ping session and compute the measured stuntime.
-
-    Args:
-        active_ping: Active continuous ping session to stop and evaluate.
-
-    Returns:
-        Measured stuntime in seconds.
-    """
-    active_ping.stop()
-    _, _, lost = active_ping.report()
-    return compute_stuntime(lost_packets=lost)
-
-
-def compute_stuntime(lost_packets: int) -> float:
-    """Compute stuntime from lost packet count.
-
-    Args:
-        lost_packets: Number of packets lost during migration.
-
-    Returns:
-        Stuntime in seconds (connectivity gap).
-    """
-    # Add +1 to account for the gap from last successful reply before loss to first successful reply after recovery
-    stuntime = 0.0 if lost_packets == 0 else (lost_packets + 1) * PING_INTERVAL_SECONDS
-    LOGGER.info(f"Stuntime: {stuntime:.1f}s (from {lost_packets} lost packets)")
-    return stuntime
-
-
 class ContinuousPing:
     """Context manager for continuous ping monitoring during VM operations.
 
@@ -141,3 +112,32 @@ def _verify_ping_reaches_destination(self) -> None:
             ],
             timeout=DEFAULT_COMMAND_TIMEOUT_SECONDS + 5,
         )
+
+
+def measure_stuntime(active_ping: ContinuousPing) -> float:
+    """Stop a continuous ping session and compute the stuntime.
+
+    Args:
+        active_ping: Active ContinuousPing session to stop and evaluate.
+
+    Returns:
+        Measured stuntime in seconds.
+    """
+    active_ping.stop()
+    _, _, lost = active_ping.report()
+    return _compute_stuntime(lost_packets=lost)
+
+
+def _compute_stuntime(lost_packets: int) -> float:
+    """Compute stuntime from lost packet count.
+
+    Args:
+        lost_packets: Number of packets lost during migration.
+
+    Returns:
+        Stuntime in seconds (connectivity gap).
+    """
+    # Add +1 to account for the gap from last successful reply before loss to first successful reply after recovery
+    stuntime = 0.0 if lost_packets == 0 else (lost_packets + 1) * PING_INTERVAL_SECONDS
+    LOGGER.info(f"Stuntime: {stuntime:.1f}s (from {lost_packets} lost packets)")
+    return stuntime

tests/network/localnet/migration_stuntime/conftest.py

@@ -11,14 +11,14 @@
 from libs.vm.vm import BaseVirtualMachine
 from tests.network.libs import cloudinit
 from tests.network.libs import cluster_user_defined_network as libcudn
+from tests.network.libs.stuntime import CLIENT_VM_LABEL, SERVER_VM_LABEL, ContinuousPing
 from tests.network.localnet.liblocalnet import (
     GUEST_1ST_IFACE_NAME,
     LOCALNET_OVS_BRIDGE_INTERFACE,
     ip_addresses_from_pool,
     libnncp,
     localnet_vm,
 )
-from tests.network.localnet.migration_stuntime.libstuntime import CLIENT_VM_LABEL, SERVER_VM_LABEL, ContinuousPing
 
 LOGGER = logging.getLogger(__name__)
 

tests/network/localnet/migration_stuntime/test_migration_stuntime.py

@@ -13,14 +13,13 @@
 Client - The connectivity initiator VM that runs continuous ping toward the server VM.
 Server - The connectivity listener VM that receives the ping and responds.
 
-STP: https://github.com/RedHatQE/openshift-virtualization-tests-design-docs/blob/main
-/stps/sig-network/stuntime_measurement.md
+STP: https://github.com/RedHatQE/openshift-virtualization-tests-design-docs/blob/main/stps/sig-network/stuntime_measurement.md
 """
 
 import pytest
 
 from libs.vm.affinity import new_pod_affinity, new_pod_anti_affinity
-from tests.network.localnet.migration_stuntime.libstuntime import (
+from tests.network.libs.stuntime import (
     CLIENT_VM_LABEL,
     SERVER_VM_LABEL,
     STUNTIME_THRESHOLD_SECONDS,