Fix issue with RKE2 servers hanging on listing apiserver addresses

pkg/agent/proxy/apiproxy.go

@@ -16,6 +16,7 @@ type Proxy interface {
 	Update(addresses []string)
 	SetAPIServerPort(ctx context.Context, port int) error
 	SetSupervisorDefault(address string)
+	IsSupervisorLBEnabled() bool
 	SupervisorURL() string
 	SupervisorAddresses() []string
 	APIServerURL() string
@@ -158,6 +159,10 @@ func (p *proxy) SetSupervisorDefault(address string) {
 	}
 }
 
+func (p *proxy) IsSupervisorLBEnabled() bool {
+	return p.supervisorLB != nil
+}
+
 func (p *proxy) SupervisorURL() string {
 	return p.supervisorURL
 }

pkg/agent/tunnel/tunnel.go

@@ -54,17 +54,23 @@ func Setup(ctx context.Context, config *config.Node, proxy proxy.Proxy) error {
 		return err
 	}
 
-	// Try to get a list of apiservers from the server we're connecting to. If that fails, fall back to
-	// querying the endpoints list from Kubernetes. This fallback requires that the server we're joining be
-	// running an apiserver, but is the only safe thing to do if its supervisor is down-level and can't provide us
-	// with an endpoint list.
-	if addresses := agentconfig.APIServers(ctx, config, proxy); len(addresses) > 0 {
-		proxy.SetSupervisorDefault(addresses[0])
-		proxy.Update(addresses)
-	} else {
-		if endpoint, _ := client.CoreV1().Endpoints("default").Get(ctx, "kubernetes", metav1.GetOptions{}); endpoint != nil {
-			if addresses := util.GetAddresses(endpoint); len(addresses) > 0 {
-				proxy.Update(addresses)
+	// The loadbalancer is only disabled when there is a local apiserver.  Servers without a local
+	// apiserver load-balance to themselves initially, then switch over to an apiserver node as soon
+	// as we get some addresses from the code below.
+	if proxy.IsSupervisorLBEnabled() && proxy.SupervisorURL() != "" {
+		logrus.Info("Getting list of apiserver endpoints from server")
+		// If not running an apiserver locally, try to get a list of apiservers from the server we're
+		// connecting to. If that fails, fall back to querying the endpoints list from Kubernetes. This
+		// fallback requires that the server we're joining be running an apiserver, but is the only safe
+		// thing to do if its supervisor is down-level and can't provide us with an endpoint list.
+		if addresses := agentconfig.APIServers(ctx, config, proxy); len(addresses) > 0 {
+			proxy.SetSupervisorDefault(addresses[0])
+			proxy.Update(addresses)
+		} else {
+			if endpoint, _ := client.CoreV1().Endpoints("default").Get(ctx, "kubernetes", metav1.GetOptions{}); endpoint != nil {
+				if addresses := util.GetAddresses(endpoint); len(addresses) > 0 {
+					proxy.Update(addresses)
+				}
 			}
 		}
 	}