Merge pull request #61459 from hzxuzhonghu/etcdv3-dial-timeout

Automatic merge from submit-queue (batch tested with PRs 62324, 61459, 62475, 62476, 61914). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

etcdv3 client: add dial timeout

dial timeout is necessary for a reliable system, this pr add it for establishing an etcd connection.

**Release note**:

```release-note
NONE
```

staging/src/k8s.io/apiserver/pkg/storage/storagebackend/factory/etcd3.go

@@ -29,11 +29,13 @@ import (
 	"k8s.io/apiserver/pkg/storage/value"
 )
 
+var (
 	// The short keepalive timeout and interval have been chosen to aggressively
 	// detect a failed etcd server without introducing much overhead.
-var (
 	keepaliveTime    = 30 * time.Second
 	keepaliveTimeout = 10 * time.Second
+	// dialTimeout is the timeout for failing to establish a connection.
+	dialTimeout = 10 * time.Second
 )
 
 func newETCD3Storage(c storagebackend.Config) (storage.Interface, DestroyFunc, error) {
@@ -52,6 +54,7 @@ func newETCD3Storage(c storagebackend.Config) (storage.Interface, DestroyFunc, e
 		tlsConfig = nil
 	}
 	cfg := clientv3.Config{
+		DialTimeout:          dialTimeout,
 		DialKeepAliveTime:    keepaliveTime,
 		DialKeepAliveTimeout: keepaliveTimeout,
 		Endpoints:            c.ServerList,