Updated wireguard-native options and added log message

pkg/agent/flannel/setup.go

@@ -169,7 +169,8 @@ func createFlannelConf(nodeConfig *config.Node) error {
 		}
 	case config.FlannelBackendWireguard:
 		backendConf = strings.ReplaceAll(wireguardBackend, "%flannelConfDir%", filepath.Dir(nodeConfig.FlannelConfFile))
-	case config.FlannelBackendNativeWireguard:
+		logrus.Warnf("The wireguard backend is deprecated and will be removed in k3s v1.26, please switch to wireguard-native. Check our docs for information about how to migrate")
+	case config.FlannelBackendWireguardNative:
 		backendConf = wireguardNativeBackend
 	default:
 		return fmt.Errorf("Cannot configure unknown flannel backend '%s'", nodeConfig.FlannelBackend)

pkg/cli/cmds/server.go

@@ -193,7 +193,7 @@ var ServerFlags = []cli.Flag{
 	ClusterDomain,
 	cli.StringFlag{
 		Name:        "flannel-backend",
-		Usage:       "(networking) One of 'none', 'vxlan', 'ipsec', 'host-gw', or 'wireguard'",
+		Usage:       "(networking) One of 'none', 'vxlan', 'ipsec', 'host-gw', 'wireguard'(deprecated), or 'wireguard-native' (default: vxlan)",
 		Destination: &ServerConfig.FlannelBackend,
 		Value:       "vxlan",
 	},

pkg/daemons/config/types.go

@@ -22,7 +22,7 @@ const (
 	FlannelBackendHostGW          = "host-gw"
 	FlannelBackendIPSEC           = "ipsec"
 	FlannelBackendWireguard       = "wireguard"
-	FlannelBackendNativeWireguard = "native-wireguard"
+	FlannelBackendWireguardNative = "wireguard-native"
 	CertificateRenewDays          = 90
 )