net: add localnet connectivity tests for dual-stream cluster

OVN localnet bridges rely on kernel bridge and OVS components that
differ between RHCOS versions. These tests verify that secondary
localnet network connectivity is preserved when the server VM migrates
between RHCOS 9 and RHCOS 10 nodes in both directions.

Signed-off-by: Asia Khromov <azhivovk@redhat.com>
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: azhivovk

tests/network/localnet/rhel9_rhel10_cluster/conftest.py

@@ -0,0 +1,105 @@
+import ipaddress
+from collections.abc import Generator
+
+import pytest
+from kubernetes.dynamic import DynamicClient
+from ocp_resources.namespace import Namespace
+from ocp_resources.node import Node
+
+import tests.network.libs.cluster_user_defined_network as libcudn
+import tests.network.libs.nodenetworkconfigurationpolicy as libnncp
+from libs.net.ip import cidr_addresses_by_family
+from libs.net.traffic_generator import TcpServer, VMTcpClient, active_tcp_connections
+from libs.net.vmspec import wait_for_ifaces_status
+from libs.vm.spec import Interface, Multus, Network
+from libs.vm.vm import BaseVirtualMachine
+from tests.network.libs import cloudinit
+from tests.network.libs.cloudinit import EthernetDevice
+from tests.network.localnet.liblocalnet import LOCALNET_BR_EX_INTERFACE, localnet_vm
+
+_LOCALNET_IFACE_GUEST_NAME = "eth1"
+_SERVER_HOST_ADDRESS = 1
+_CLIENT_HOST_ADDRESS = 2
+
+
+@pytest.fixture(scope="module")
+def localnet_server_vm(
+    unprivileged_client: DynamicClient,
+    namespace_localnet_1: Namespace,
+    cudn_localnet: libcudn.ClusterUserDefinedNetwork,
+    nncp_localnet: libnncp.NodeNetworkConfigurationPolicy,
+    rhcos9_node: Node,
+) -> Generator[BaseVirtualMachine]:
+    addresses = cidr_addresses_by_family(net_seed=0, host_address=_SERVER_HOST_ADDRESS)
+    with localnet_vm(
+        namespace=namespace_localnet_1.name,
+        name="server-vm",
+        client=unprivileged_client,
+        networks=[
+            Network(name="default", pod={}),
+            Network(name=LOCALNET_BR_EX_INTERFACE, multus=Multus(networkName=cudn_localnet.name)),
+        ],
+        interfaces=[
+            Interface(name="default", masquerade={}),
+            Interface(name=LOCALNET_BR_EX_INTERFACE, bridge={}),
+        ],
+        network_data=cloudinit.NetworkData(ethernets={_LOCALNET_IFACE_GUEST_NAME: EthernetDevice(addresses=addresses)}),
+        node=rhcos9_node,
+    ) as vm:
+        vm.start(wait=True)
+        vm.wait_for_agent_connected()
+        wait_for_ifaces_status(
+            vm=vm,
+            ip_addresses_by_spec_net_name={
+                LOCALNET_BR_EX_INTERFACE: [str(ipaddress.ip_interface(addr).ip) for addr in addresses]
+            },
+        )
+        yield vm
+
+
+@pytest.fixture(scope="module")
+def localnet_client_vm(
+    unprivileged_client: DynamicClient,
+    namespace_localnet_1: Namespace,
+    cudn_localnet: libcudn.ClusterUserDefinedNetwork,
+    nncp_localnet: libnncp.NodeNetworkConfigurationPolicy,
+    rhcos9_node: Node,
+) -> Generator[BaseVirtualMachine]:
+    addresses = cidr_addresses_by_family(net_seed=0, host_address=_CLIENT_HOST_ADDRESS)
+    with localnet_vm(
+        namespace=namespace_localnet_1.name,
+        name="client-vm",
+        client=unprivileged_client,
+        networks=[
+            Network(name="default", pod={}),
+            Network(name=LOCALNET_BR_EX_INTERFACE, multus=Multus(networkName=cudn_localnet.name)),
+        ],
+        interfaces=[
+            Interface(name="default", masquerade={}),
+            Interface(name=LOCALNET_BR_EX_INTERFACE, bridge={}),
+        ],
+        network_data=cloudinit.NetworkData(ethernets={_LOCALNET_IFACE_GUEST_NAME: EthernetDevice(addresses=addresses)}),
+        node=rhcos9_node,
+    ) as vm:
+        vm.start(wait=True)
+        vm.wait_for_agent_connected()
+        wait_for_ifaces_status(
+            vm=vm,
+            ip_addresses_by_spec_net_name={
+                LOCALNET_BR_EX_INTERFACE: [str(ipaddress.ip_interface(addr).ip) for addr in addresses]
+            },
+        )
+        yield vm
+
+
+@pytest.fixture(scope="module")
+def localnet_active_tcp_connection(
+    localnet_client_vm: BaseVirtualMachine,
+    localnet_server_vm: BaseVirtualMachine,
+) -> Generator[list[tuple[VMTcpClient, TcpServer]]]:
+    with active_tcp_connections(
+        client_vm=localnet_client_vm,
+        server_vm=localnet_server_vm,
+        iface_name=LOCALNET_BR_EX_INTERFACE,
+    ) as connections:
+        yield connections

tests/network/localnet/rhel9_rhel10_cluster/test_connectivity.py

@@ -8,11 +8,16 @@
     - mixed_os_nodes
 """
 
+import ipaddress
+
 import pytest
 
-__test__ = False
+from libs.net.traffic_generator import is_tcp_connection
+from tests.network.libs.nodes import update_vm_node_selector
+from utilities.virt import migrate_vm_and_verify
 
 
+@pytest.mark.mixed_os_nodes
 @pytest.mark.incremental
 class TestConnectivity:
     """
@@ -23,7 +28,13 @@ class TestConnectivity:
     """
 
     @pytest.mark.polarion("CNV-15951")
-    def test_connectivity_preserved_during_server_migration_to_rhcos10(self):
+    def test_connectivity_preserved_during_server_migration_to_rhcos10(
+        self,
+        subtests,
+        localnet_server_vm,
+        rhcos10_node,
+        localnet_active_tcp_connection,
+    ):
         """
         Test that an active TCP connection over a secondary localnet network
         is preserved when the server VM migrates from an RHCOS 9 node to an RHCOS 10 node.
@@ -39,9 +50,22 @@ def test_connectivity_preserved_during_server_migration_to_rhcos10(self):
         Expected:
             - The active TCP connection from the client VM to the server VM is preserved during the migration
         """
+        update_vm_node_selector(vm=localnet_server_vm, node=rhcos10_node)
+        migrate_vm_and_verify(vm=localnet_server_vm)
+        for client, server in localnet_active_tcp_connection:
+            with subtests.test(msg=f"IPv{ipaddress.ip_address(client.server_ip).version} after migration to RHCOS 10"):
+                assert is_tcp_connection(server=server, client=client), (
+                    f"TCP connection lost after migrating {localnet_server_vm.name} to RHCOS 10 node"
+                )
 
     @pytest.mark.polarion("CNV-15966")
-    def test_connectivity_preserved_during_server_migration_to_rhcos9(self):
+    def test_connectivity_preserved_during_server_migration_to_rhcos9(
+        self,
+        subtests,
+        localnet_server_vm,
+        rhcos9_node,
+        localnet_active_tcp_connection,
+    ):
         """
         Test that an active TCP connection over a secondary localnet network
         is preserved when the server VM migrates from an RHCOS 10 node to an RHCOS 9 node.
@@ -57,3 +81,12 @@ def test_connectivity_preserved_during_server_migration_to_rhcos9(self):
         Expected:
             - The active TCP connection from the client VM to the server VM is preserved during the migration
         """
+        update_vm_node_selector(vm=localnet_server_vm, node=rhcos9_node)
+        migrate_vm_and_verify(vm=localnet_server_vm)
+        for client, server in localnet_active_tcp_connection:
+            with subtests.test(
+                msg=f"IPv{ipaddress.ip_address(client.server_ip).version} after migration back to RHCOS 9"
+            ):
+                assert is_tcp_connection(server=server, client=client), (
+                    f"TCP connection lost after migrating {localnet_server_vm.name} back to RHCOS 9 node"
+                )