Support setting control server URL for Tailscale.

pkg/agent/flannel/setup.go

@@ -76,7 +76,7 @@ const (
 
 	tailscaledBackend = `{
 	"Type": "extension",
-	"PostStartupCommand": "tailscale up --accept-routes --advertise-routes=%Routes%",
+	"PostStartupCommand": "tailscale set --accept-routes --advertise-routes=%Routes%",
 	"ShutdownCommand": "tailscale down"
 }`
 

pkg/cli/cmds/agent.go

@@ -155,13 +155,13 @@ var (
 	}
 	VPNAuth = &cli.StringFlag{
 		Name:        "vpn-auth",
-		Usage:       "(agent/networking) (experimental) Credentials for the VPN provider. It must include the provider name and join key in the format name=<vpn-provider>,joinKey=<key>",
+		Usage:       "(agent/networking) (experimental) Credentials for the VPN provider. It must include the provider name and join key in the format name=<vpn-provider>,joinKey=<key>[,controlServerURL=<url>]",
 		EnvVar:      version.ProgramUpper + "_VPN_AUTH",
 		Destination: &AgentConfig.VPNAuth,
 	}
 	VPNAuthFile = &cli.StringFlag{
 		Name:        "vpn-auth-file",
-		Usage:       "(agent/networking) (experimental) File containing credentials for the VPN provider. It must include the provider name and join key in the format name=<vpn-provider>,joinKey=<key>",
+		Usage:       "(agent/networking) (experimental) File containing credentials for the VPN provider. It must include the provider name and join key in the format name=<vpn-provider>,joinKey=<key>[,controlServerURL=<url>]",
 		EnvVar:      version.ProgramUpper + "_VPN_AUTH_FILE",
 		Destination: &AgentConfig.VPNAuthFile,
 	}

pkg/vpn/vpn.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net"
+	"net/url"
 	"strings"
 
 	"github.com/k3s-io/k3s/pkg/util"
@@ -31,8 +32,9 @@ type VPNInfo struct {
 
 // vpnCliAuthInfo includes auth information of the VPN. It is a general struct in case we want to add more vpn integrations
 type vpnCliAuthInfo struct {
-	Name    string
-	JoinKey string
+	Name             string
+	JoinKey          string
+	ControlServerURL string
 }
 
 // StartVPN starts the VPN interface. General function in case we want to add more vpn integrations
@@ -45,7 +47,13 @@ func StartVPN(vpnAuthConfigFile string) error {
 	logrus.Infof("Starting VPN: %s", authInfo.Name)
 	switch authInfo.Name {
 	case "tailscale":
-		output, err := util.ExecCommand("tailscale", []string{"up", "--authkey", authInfo.JoinKey, "--reset"})
+		args := []string{
+			"up", "--authkey", authInfo.JoinKey, "--timeout=30s", "--reset",
+		}
+		if authInfo.ControlServerURL != "" {
+			args = append(args, "--login-server", authInfo.ControlServerURL)
+		}
+		output, err := util.ExecCommand("tailscale", args)
 		if err != nil {
 			return errors.Wrap(err, "tailscale up failed: "+output)
 		}
@@ -80,6 +88,8 @@ func getVPNAuthInfo(vpnAuth string) (vpnCliAuthInfo, error) {
 			authInfo.Name = vpnKeyValue[1]
 		case "joinKey":
 			authInfo.JoinKey = vpnKeyValue[1]
+		case "controlServerURL":
+			authInfo.ControlServerURL = vpnKeyValue[1]
 		default:
 			return vpnCliAuthInfo{}, fmt.Errorf("VPN Error. The passed VPN auth info includes an unknown parameter: %v", vpnKeyValue[0])
 		}
@@ -97,6 +107,11 @@ func isVPNConfigOK(authInfo vpnCliAuthInfo) error {
 		if authInfo.JoinKey == "" {
 			return errors.New("VPN Error. Tailscale requires a JoinKey")
 		}
+		if authInfo.ControlServerURL != "" {
+			if _, err := url.Parse(authInfo.ControlServerURL); err != nil {
+				return fmt.Errorf("VPN Error. Invalid control server URL for Tailscale: %w", err)
+			}
+		}
 		return nil
 	}