localnet, multi-homing: introduce localnet alias

Having a different parameter to use as the network_name option of the
localnet logical switch port allows the admin to create multiple
physical network attachment without having to reconfigure the physical
OVN bridge mappings.

This improves the admin's UX (less operations) and solution scalability
(since a single mapping can be re-used) and thus the size of the
ovn-bridge-mappings string can be kept low.

Signed-off-by: Miguel Duarte Barroso <mdbarroso@redhat.com>

go-controller/pkg/cni/types/types.go

@@ -33,6 +33,8 @@ type NetConf struct {
 	// restart.
 	AllowPersistentIPs bool `json:"allowPersistentIPs,omitempty"`
 
+	Alias string `json:"alias,omitempty"`
+
 	// PciAddrs in case of using sriov or Auxiliry device name in case of SF
 	DeviceID string `json:"deviceID,omitempty"`
 	// LogFile to log all the messages from cni shim binary to

go-controller/pkg/ovn/secondary_localnet_network_controller.go

@@ -116,16 +116,21 @@ func (oc *SecondaryLocalnetNetworkController) Init() error {
 		return err
 	}
 
+	localnetPortNetNameOption := map[string]string{
+		"network_name": oc.GetNetworkName(),
+	}
+	if oc.NetInfo.Alias() != "" {
+		localnetPortNetNameOption["network_name"] = oc.NetInfo.Alias()
+	}
+
 	// Add external interface as a logical port to external_switch.
 	// This is a learning switch port with "unknown" address. The external
 	// world is accessed via this port.
 	logicalSwitchPort := nbdb.LogicalSwitchPort{
 		Name:      oc.GetNetworkScopedName(types.OVNLocalnetPort),
 		Addresses: []string{"unknown"},
 		Type:      "localnet",
-		Options: map[string]string{
-			"network_name": oc.GetNetworkName(),
-		},
+		Options:   localnetPortNetNameOption,
 	}
 	intVlanID := int(oc.Vlan())
 	if intVlanID != 0 {

go-controller/pkg/util/multi_network.go

@@ -36,6 +36,7 @@ type BasicNetInfo interface {
 	ExcludeSubnets() []*net.IPNet
 	Vlan() uint
 	AllowsPersistentIPs() bool
+	Alias() string
 
 	// utility methods
 	CompareNetInfo(BasicNetInfo) bool
@@ -133,6 +134,10 @@ func (nInfo *DefaultNetInfo) AllowsPersistentIPs() bool {
 	return false
 }
 
+func (nInfo *DefaultNetInfo) Alias() string {
+	return ""
+}
+
 // SecondaryNetInfo holds the network name information for secondary network if non-nil
 type secondaryNetInfo struct {
 	netName            string
@@ -148,6 +153,8 @@ type secondaryNetInfo struct {
 	// all net-attach-def NAD names for this network, used to determine if a pod needs
 	// to be plumbed for this network
 	nadNames sync.Map
+
+	localnetAlias string
 }
 
 // GetNetworkName returns the network name
@@ -215,6 +222,10 @@ func (nInfo *secondaryNetInfo) AllowsPersistentIPs() bool {
 	return nInfo.allowPersistentIPs
 }
 
+func (nInfo *secondaryNetInfo) Alias() string {
+	return nInfo.localnetAlias
+}
+
 // IPMode returns the ipv4/ipv6 mode
 func (nInfo *secondaryNetInfo) IPMode() (bool, bool) {
 	return nInfo.ipv4mode, nInfo.ipv6mode
@@ -305,6 +316,7 @@ func newLocalnetNetConfInfo(netconf *ovncnitypes.NetConf) (NetInfo, error) {
 		mtu:                netconf.MTU,
 		vlan:               uint(netconf.VLANID),
 		allowPersistentIPs: netconf.AllowPersistentIPs,
+		localnetAlias:      netconf.Alias,
 	}
 	ni.ipv4mode, ni.ipv6mode = getIPMode(subnets)
 	return ni, nil