network, bridge binding: Enable container interface

Migrating a VM with secondary interfaces that uses bridge binding may cause long
periods of traffic disruption. This occurs when the interface is defined with an
explicit MAC address (manually or automatically through KubeMacPool) on nodes
that have IPv6 enabled.

During the migration, frames may be forwarded to the destination node while the
domain is active on the source and still not running at the destination.

When the migration destination pod is created an IPv6 NS (Neighbor Solicitation)
and NA (Neighbor Advertisement) are sent automatically by the kernel.
The switches at the endpoints (e.g.: migration destination node) tables
get updated and the traffic is forwarded to the migration destination before
the migration is completed [1].

Assuming the used bridge CNI to connect the pod to the node can create the pod
interface in a "link-down" state [2], the IPv6 NS/NA packets are avoided.
However, there is a need to explicitly set the "link-up" when Kubevirt later
processes them.

As part of the pod network configuration calculation, Kubevirt now explicitly
asks to set the relevant interfaces for the bridge binding as "UP".

Fixes: https://issues.redhat.com/browse/CNV-28040

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2186372#c6
[2] containernetworking/plugins#951

Signed-off-by: Or Mergi <ormergi@redhat.com>

pkg/network/setup/netpod/netpod.go

@@ -330,6 +330,7 @@ func (n NetPod) bridgeBindingSpec(podIfaceName string, vmiIfaceIndex int, ifaceS
 	podIface := nmstate.Interface{
 		Index:       podStatusIface.Index,
 		Name:        podIfaceAlternativeName,
+		State:       nmstate.IfaceStateUp,
 		CopyMacFrom: bridgeIface.Name,
 		Controller:  bridgeIface.Name,
 		IPv4:        nmstate.IP{Enabled: pointer.P(false)},

pkg/network/setup/netpod/netpod_test.go

@@ -362,6 +362,7 @@ var _ = Describe("netpod", func() {
 						Index:       0,
 						CopyMacFrom: "k6t-eth0",
 						Controller:  "k6t-eth0",
+						State:       nmstate.IfaceStateUp,
 						IPv4:        ipDisabled,
 						IPv6:        ipDisabled,
 						LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},
@@ -470,6 +471,7 @@ var _ = Describe("netpod", func() {
 						Index:       0,
 						CopyMacFrom: "k6t-eth0",
 						Controller:  "k6t-eth0",
+						State:       nmstate.IfaceStateUp,
 						IPv4:        ipDisabled,
 						IPv6:        ipDisabled,
 						LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},
@@ -678,6 +680,7 @@ var _ = Describe("netpod", func() {
 							Index:       secondaryPodInterfaceIndex,
 							CopyMacFrom: "k6t-914f438d88d",
 							Controller:  "k6t-914f438d88d",
+							State:       nmstate.IfaceStateUp,
 							IPv4:        ipDisabled,
 							IPv6:        ipDisabled,
 							LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},
@@ -860,6 +863,7 @@ var _ = Describe("netpod", func() {
 							Index:       secondaryPodInterfaceIndex,
 							CopyMacFrom: "k6t-net1",
 							Controller:  "k6t-net1",
+							State:       nmstate.IfaceStateUp,
 							IPv4:        ipDisabled,
 							IPv6:        ipDisabled,
 							LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},
@@ -1135,6 +1139,7 @@ var _ = Describe("netpod", func() {
 							Name:        "bc6cc93fa1e-nic",
 							CopyMacFrom: "k6t-bc6cc93fa1e",
 							Controller:  "k6t-bc6cc93fa1e",
+							State:       nmstate.IfaceStateUp,
 							IPv4:        ipDisabled,
 							IPv6:        ipDisabled,
 							LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},
@@ -1338,6 +1343,7 @@ var _ = Describe("netpod", func() {
 							Name:        "7087ef4cd1f-nic",
 							CopyMacFrom: "k6t-7087ef4cd1f",
 							Controller:  "k6t-7087ef4cd1f",
+							State:       nmstate.IfaceStateUp,
 							IPv4:        ipDisabled,
 							IPv6:        ipDisabled,
 							LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},
@@ -1536,6 +1542,7 @@ var _ = Describe("netpod", func() {
 						Name:        "7087ef4cd1f-nic",
 						CopyMacFrom: "k6t-7087ef4cd1f",
 						Controller:  "k6t-7087ef4cd1f",
+						State:       nmstate.IfaceStateUp,
 						IPv4:        ipDisabled,
 						IPv6:        ipDisabled,
 						LinuxStack:  nmstate.LinuxIfaceStack{PortLearning: pointer.P(false)},