virt-handler, podIfaceName discovery: support not found links

The VM can hotplugged interface that weren't yet plugged to the pod, it
is a valid scenario.

Signed-off-by: Alona Paz <[email protected]>

pkg/network/link/discovery.go

@@ -20,6 +20,7 @@
 package link
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 
@@ -34,6 +35,7 @@ import (
 // DiscoverByNetwork return the pod interface link of the given network name.
 // If link not found, it will try to get the link using the pod interface's ordinal name (net1, net2,...)
 // based on the subject network position in the given networks slice.
+// If no link is found, a nil link will be returned.
 func DiscoverByNetwork(handler driver.NetworkHandler, networks []v1.Network, subjectNetwork v1.Network) (netlink.Link, error) {
 	ifaceNames, err := networkInterfaceNames(networks, subjectNetwork)
 	if err != nil {
@@ -60,7 +62,13 @@ func linkByNames(handler driver.NetworkHandler, names []string) (netlink.Link, e
 		if err == nil {
 			return link, nil
 		}
-		errs = append(errs, fmt.Sprintf("could not get link with name %q: %v", name, err))
+		var linkNotFoundErr netlink.LinkNotFoundError
+		if !errors.As(err, &linkNotFoundErr) {
+			errs = append(errs, fmt.Sprintf("could not get link with name %q: %v", name, err))
+		}
+	}
+	if len(errs) == 0 {
+		return nil, nil
 	}
 	return nil, fmt.Errorf(strings.Join(errs, ", "))
 }

pkg/network/setup/network.go

@@ -137,7 +137,7 @@ func preConfigStateRun(nics []podNIC) ([]podNIC, error) {
 
 func discoverPodInterfaces(nics []podNIC) ([]podNIC, error) {
 	for idx, nic := range nics {
-		podIfaceName, err := discoverPodInterfaceName(nic.handler, nic.vmi.Spec.Networks, *nic.vmiSpecNetwork, *nic.vmiSpecIface)
+		podIfaceName, err := discoverPodInterfaceName(nic.handler, nic.vmi.Spec.Networks, *nic.vmiSpecNetwork)
 		if err != nil {
 			return nil, err
 		}
@@ -146,15 +146,15 @@ func discoverPodInterfaces(nics []podNIC) ([]podNIC, error) {
 	return nics, nil
 }
 
-func discoverPodInterfaceName(handler netdriver.NetworkHandler, networks []v1.Network, subjectNetwork v1.Network, subjectedIface v1.Interface) (string, error) {
+func discoverPodInterfaceName(handler netdriver.NetworkHandler, networks []v1.Network, subjectNetwork v1.Network) (string, error) {
 	ifaceLink, err := link.DiscoverByNetwork(handler, networks, subjectNetwork)
 	if err != nil {
-		if subjectedIface.State != v1.InterfaceStateAbsent {
-			return "", err
-		}
-		// For a network marked for removal, it is reasonable not to find any interface.
-		return "", nil
+		return "", err
 	} else {
+		if ifaceLink == nil {
+			// couldn't find any interface
+			return "", nil
+		}
 		return ifaceLink.Attrs().Name, nil
 	}
 }
@@ -179,7 +179,7 @@ func (n *VMNetworkConfigurator) UnplugPodNetworksPhase1(vmi *v1.VirtualMachineIn
 		func() (map[string]string, error) {
 			podIfaceNameByNet := map[string]string{}
 			for _, net := range vmi.Spec.Networks {
-				podIfaceName, err := discoverPodInterfaceName(n.handler, vmi.Spec.Networks, net, *vmispec.LookupInterfaceByName(vmi.Spec.Domain.Devices.Interfaces, net.Name))
+				podIfaceName, err := discoverPodInterfaceName(n.handler, vmi.Spec.Networks, net)
 				if err != nil {
 					return nil, err
 				}

pkg/network/setup/podnic.go

@@ -96,7 +96,11 @@ func newPhase2PodNIC(vmi *v1.VirtualMachineInstance, network *v1.Network, handle
 	if err != nil {
 		return nil, err
 	}
-	podnic.podInterfaceName = ifaceLink.Attrs().Name
+	if ifaceLink == nil {
+		podnic.podInterfaceName = ""
+	} else {
+		podnic.podInterfaceName = ifaceLink.Attrs().Name
+	}
 
 	podnic.dhcpConfigurator = podnic.newDHCPConfigurator()
 	podnic.domainGenerator = podnic.newLibvirtSpecGenerator(domain)