iotopo / vrrp-go

VRRP implement

vrrp-go

由golang实现的VRRP-v3, 点击超链接获取关于VRRP的信息。

VRRP-v3 implemented by golang，click hyperlink get details about VRRP

Platforms support

Only linux is currently supported and tested.

Dependencies

In order to forward virtual IP traffic to local IP, iptables binary is required.

Example

package main

import (
	"context"
	"flag"
	"fmt"
	"net"
	"net/http"
	"os"
	"os/signal"
	"time"

	"github.com/sirupsen/logrus"

	vrrp "go.linka.cloud/vrrp-go"
)

var (
	vrid     int
	priority int
	iface    string
	preemt   bool
)

func init() {
	flag.IntVar(&vrid, "vrid", 233, "virtual router id")
	flag.IntVar(&priority, "pri", 100, "router priority")
	flag.StringVar(&iface, "iface", "eth0", "network interface")
	flag.BoolVar(&preemt, "preempt", false, "set preempt mode")
}

func main() {
	vips := []string{"172.17.0.42", "172.17.0.43"}
	log := logrus.StandardLogger()
	flag.Parse()
	vrrp.SetLogLevel(logrus.InfoLevel)
	var ips []net.IP
	for _, v := range vips {
		ips = append(ips, net.ParseIP(v))
	}
	vr, err := vrrp.NewVirtualRouter(
		vrrp.WithVRID(byte(vrid)),
		vrrp.WithInterface(iface),
		vrrp.WithAdvInterval(100*time.Millisecond),
		vrrp.WithPriority(byte(priority)),
		vrrp.WithMasterAdvInterval(100*time.Millisecond),
		vrrp.WithPreemtpMode(preemt),
		vrrp.WithIPvXAddr(ips...),
	)
	if err != nil {
		log.Fatal(err)
	}
	var hctx context.Context
	var hcancel func()
	handle := func(t vrrp.Transition) {
		switch t {
		case vrrp.Backup2Master:
			log.Info("init to master")
			hctx, hcancel = context.WithCancel(context.Background())
			go run(hctx)
		case vrrp.Master2Init:
			log.Info("master to init")
			hcancel()
		case vrrp.Master2Backup:
			log.Info("master to backup")
			hcancel()
		}
	}
	ch := make(chan vrrp.Transition, 10)
	go vr.StartWithEventSelector(ch)
	sigs := make(chan os.Signal)
	signal.Notify(sigs, os.Kill, os.Interrupt)
	for {
		select {
		case t := <-ch:
			handle(t)
		case s := <-sigs:
			fmt.Println()
			if hcancel != nil {
				hcancel()
			}
			log.Warnf("received: %v", s)
			log.Warn("exiting...")
			vr.Stop()
			os.Exit(1)
		}
	}

}

func run(ctx context.Context) {
	errs := make(chan error, 1)
	mux := http.NewServeMux()
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		logrus.Infof(r.RemoteAddr)
		w.Write([]byte("ok"))
	})
	srv := http.Server{
		Addr:    ":8888",
		Handler: mux,
	}
	go func() {
		errs <- srv.ListenAndServe()
	}()
	for {
		select {
		case err := <-errs:
			logrus.WithError(err).Error("web server stopped")
		case <-ctx.Done():
			logrus.Warn(ctx.Err())
			srv.Shutdown(context.Background())
			return
		}
	}
}

GOOS=linux go build -o vr example/main.go
#execute on host1
./vr -vrid=200 -pri=150
#execute on host2
./vr -vrid=200 -pri=230