Increase maxIdleConnection limit in etcd client.

cmd/kube-apiserver/app/server.go

@@ -39,6 +39,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/master"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	forked "github.com/GoogleCloudPlatform/kubernetes/third_party/forked/coreos/go-etcd/etcd"
 
 	"github.com/coreos/go-etcd/etcd"
 	"github.com/golang/glog"
@@ -192,7 +193,16 @@ func newEtcd(etcdConfigFile string, etcdServerList util.StringList, storageVersi
 			return helper, err
 		}
 	} else {
-		client = etcd.NewClient(etcdServerList)
+		etcdClient := etcd.NewClient(etcdServerList)
+		transport := &http.Transport{
+			Dial: forked.Dial,
+			TLSClientConfig: &tls.Config{
+				InsecureSkipVerify: true,
+			},
+			MaxIdleConnsPerHost: 500,
+		}
+		etcdClient.SetTransport(transport)
+		client = etcdClient
 	}
 
 	return master.NewEtcdHelper(client, storageVersion, pathPrefix)

third_party/forked/coreos/go-etcd/etcd/client.go

+package etcd
+
+import (
+	"errors"
+	"net"
+	"time"
+)
+
+// dial attempts to open a TCP connection to the provided address, explicitly
+// enabling keep-alives with a one-second interval.
+func Dial(network, addr string) (net.Conn, error) {
+	conn, err := net.DialTimeout(network, addr, time.Second)
+	if err != nil {
+		return nil, err
+	}
+
+	tcpConn, ok := conn.(*net.TCPConn)
+	if !ok {
+		return nil, errors.New("Failed type-assertion of net.Conn as *net.TCPConn")
+	}
+
+	// Keep TCP alive to check whether or not the remote machine is down
+	if err = tcpConn.SetKeepAlive(true); err != nil {
+		return nil, err
+	}
+
+	if err = tcpConn.SetKeepAlivePeriod(time.Second); err != nil {
+		return nil, err
+	}
+
+	return tcpConn, nil
+}