controller: fix apiserver connection timeout on startup (#2545)

pkg/controller/config.go

@@ -12,10 +12,10 @@ import (
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/klog/v2"
+	"kubevirt.io/client-go/kubecli"
 
 	clientset "github.com/kubeovn/kube-ovn/pkg/client/clientset/versioned"
 	"github.com/kubeovn/kube-ovn/pkg/util"
-	"kubevirt.io/client-go/kubecli"
 )
 
 // Configuration is the controller conf
@@ -290,6 +290,13 @@ func (config *Configuration) initKubeClient() error {
 		klog.Errorf("failed to build kubeconfig %v", err)
 		return err
 	}
+
+	// try to connect to apiserver's tcp port
+	if err = util.DialApiServer(cfg.Host); err != nil {
+		klog.Errorf("failed to dial apiserver: %v", err)
+		return err
+	}
+
 	cfg.QPS = 1000
 	cfg.Burst = 2000
 	// use cmd arg to modify timeout later

pkg/daemon/config.go

@@ -322,6 +322,13 @@ func (config *Configuration) initKubeClient() error {
 			return err
 		}
 	}
+
+	// try to connect to apiserver's tcp port
+	if err = util.DialApiServer(cfg.Host); err != nil {
+		klog.Errorf("failed to dial apiserver: %v", err)
+		return err
+	}
+
 	cfg.QPS = 1000
 	cfg.Burst = 2000
 

pkg/util/k8s.go

@@ -1,11 +1,39 @@
 package util
 
 import (
+	"fmt"
+	"net"
+	"net/url"
 	"strings"
+	"time"
 
 	v1 "k8s.io/api/core/v1"
+	"k8s.io/klog/v2"
 )
 
+func DialApiServer(host string) error {
+	u, err := url.Parse(host)
+	if err != nil {
+		return fmt.Errorf("failed to parse host %q: %v", host, err)
+	}
+
+	address := net.JoinHostPort(u.Hostname(), u.Port())
+	timer := time.NewTimer(3 * time.Second)
+	for i := 0; i < 10; i++ {
+		conn, err := net.DialTimeout("tcp", address, 3*time.Second)
+		if err == nil {
+			klog.Infof("succeeded to dial apiserver %q", address)
+			_ = conn.Close()
+			return nil
+		}
+		klog.Warningf("failed to dial apiserver %q: %v", address, err)
+		<-timer.C
+		timer.Reset(3 * time.Second)
+	}
+
+	return fmt.Errorf("timed out dialing apiserver %q", host)
+}
+
 func GetNodeInternalIP(node v1.Node) (ipv4, ipv6 string) {
 	var ips []string
 	for _, addr := range node.Status.Addresses {