net: add option to make vmnet the default route

cmd/start.go

@@ -191,6 +191,7 @@ func init() {
 		startCmd.Flags().BoolVar(&startCmdArgs.Network.Address, "network-address", false, "assign reachable IP address to the VM")
 		startCmd.Flags().StringVar(&startCmdArgs.Network.Mode, "network-mode", "shared", "network mode (shared, bridged)")
 		startCmd.Flags().StringVar(&startCmdArgs.Network.BridgeInterface, "network-interface", "en0", "host network interface to use for bridged mode")
+		startCmd.Flags().BoolVar(&startCmdArgs.Network.PreferredRoute, "network-preferred-route", false, "use the assigned IP address as the preferred route for the VM (implies --network-address)")
 
 		// vm type
 		if util.MacOS13OrNewer() {
@@ -535,6 +536,9 @@ func prepareConfig(cmd *cobra.Command) {
 		if !cmd.Flag("network-interface").Changed {
 			startCmdArgs.Network.BridgeInterface = current.Network.BridgeInterface
 		}
+		if !cmd.Flag("network-preferred-route").Changed {
+			startCmdArgs.Network.PreferredRoute = current.Network.PreferredRoute
+		}
 		if util.MacOS13OrNewer() {
 			if !cmd.Flag("vm-type").Changed {
 				startCmdArgs.VMType = current.VMType

config/config.go

@@ -84,6 +84,7 @@ type Network struct {
 	HostAddresses   bool              `yaml:"hostAddresses"`
 	Mode            string            `yaml:"mode"` // shared, bridged
 	BridgeInterface string            `yaml:"interface"`
+	PreferredRoute  bool              `yaml:"preferredRoute"`
 }
 
 // Mount is volume mount

embedded/defaults/colima.yaml

@@ -70,6 +70,11 @@ network:
   # Default: en0
   interface: en0
 
+  # Use the assigned IP address as the preferred route for the VM.
+  # Note: this only has an effect when `address` is set to true.
+  # Default: false
+  preferredRoute: false
+
   # Custom DNS resolvers for the virtual machine.
   #
   # EXAMPLE

environment/vm/lima/limautil/network.go

@@ -9,7 +9,8 @@ import (
 const NetInterface = "col0"
 
 // network metric for the route
-const NetMetric = 300
+const NetMetric uint32 = 300
+const NetMetricPreferred uint32 = 100
 
 // IPAddress returns the ip address for profile.
 // It returns the PTP address if networking is enabled or falls back to 127.0.0.1.

environment/vm/lima/yaml.go

@@ -133,12 +133,16 @@ func newConf(ctx context.Context, conf config.Config) (l limaconfig.Config, err
 
 		reachableIPAddress := true
 		if conf.Network.Address {
+			metric := limautil.NetMetric
+			if conf.Network.PreferredRoute {
+				metric = limautil.NetMetricPreferred
+			}
 			// vmnet is always used for incus runtime or bridged mode
 			if l.VMType == limaconfig.VZ && conf.Runtime != incus.Name && conf.Network.Mode != "bridged" {
 				l.Networks = append(l.Networks, limaconfig.Network{
 					VZNAT:     true,
 					Interface: limautil.NetInterface,
-					Metric:    limautil.NetMetric,
+					Metric:    metric,
 				})
 			} else {
 				reachableIPAddress, _ = ctx.Value(daemon.CtxKey(vmnet.Name)).(bool)
@@ -155,7 +159,7 @@ func newConf(ctx context.Context, conf config.Config) (l limaconfig.Config, err
 						l.Networks = append(l.Networks, limaconfig.Network{
 							Socket:    socketFile,
 							Interface: limautil.NetInterface,
-							Metric:    limautil.NetMetric,
+							Metric:    metric,
 						})
 
 						return nil