golang 1.11 supports SO_REUSEPORT

socket.go

package main

import (
	"context"
	"fmt"
	"net"
	"net/http"
	"syscall"

	"golang.org/x/sys/unix"
)

func main() {
	http.HandleFunc("/hello", handler)

	lc := net.ListenConfig{
		Control: listenCtrl,
	}
	l, err := lc.Listen(context.Background(), "tcp4", ":8080")
	if err != nil {
		panic(err)
	}

	svc := http.Server{}
	err = svc.Serve(l)
	if err != nil {
		panic(err)
	}
}

func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Println("This server")
	fmt.Fprintf(w, "Hello, World\n")
}

func listenCtrl(network string, address string, c syscall.RawConn) error {
	var operr error
	var fn = func(s uintptr) {
		operr = unix.SetsockoptInt(int(s), unix.SOL_SOCKET, unix.SO_REUSEPORT, 1)
	}
	if err := c.Control(fn); err != nil {
		return err
	}
	if operr != nil {
		return operr
	}
	return nil
}