コード例 #1
0
func StartServer(vshost string, me string) *PBServer {
	pb := new(PBServer)
	pb.me = me
	pb.vs = viewservice.MakeClerk(me, vshost)
	// Your pb.* initializations here.
	pb.view = viewservice.View{}
	pb.content = make(map[string]string)
	pb.client = make(map[string]string)

	rpcs := rpc.NewServer()
	rpcs.Register(pb)

	os.Remove(pb.me)
	l, e := net.Listen("unix", pb.me)
	if e != nil {
		log.Fatal("listen error: ", e)
	}
	pb.l = l

	// please do not change any of the following code,
	// or do anything to subvert it.

	go func() {
		for pb.isdead() == false {
			conn, err := pb.l.Accept()
			if err == nil && pb.isdead() == false {
				if pb.isunreliable() && (rand.Int63()%1000) < 100 {
					// discard the request.
					conn.Close()
				} else if pb.isunreliable() && (rand.Int63()%1000) < 200 {
					// process the request but force discard of reply.
					c1 := conn.(*net.UnixConn)
					f, _ := c1.File()
					err := syscall.Shutdown(int(f.Fd()), syscall.SHUT_WR)
					if err != nil {
						fmt.Printf("shutdown: %v\n", err)
					}
					go rpcs.ServeConn(conn)
				} else {
					go rpcs.ServeConn(conn)
				}
			} else if err == nil {
				conn.Close()
			}
			if err != nil && pb.isdead() == false {
				fmt.Printf("PBServer(%v) accept: %v\n", me, err.Error())
				pb.kill()
			}
		}
	}()

	go func() {
		for pb.isdead() == false {
			pb.tick()
			time.Sleep(viewservice.PingInterval)
		}
	}()

	return pb
}
コード例 #2
0
ファイル: client.go プロジェクト: salibrandi/mexos
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.me = me
	return ck
}
コード例 #3
0
ファイル: client.go プロジェクト: salmanahmad/6.824
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	ck.view, _ = ck.vs.Get()

	return ck
}
コード例 #4
0
ファイル: client.go プロジェクト: ChenLingPeng/6.824
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.me = fmt.Sprintf("%s%d", me, nrand())

	return ck
}
コード例 #5
0
ファイル: client.go プロジェクト: ctliu3/yds
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.me = "client: " + strconv.Itoa(int(nrand()))

	return ck
}
コード例 #6
0
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.currentView = viewservice.View{0, "", ""}

	return ck
}
コード例 #7
0
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.id = nrand()
	ck.seq_num = 0
	return ck
}
コード例 #8
0
ファイル: test_test.go プロジェクト: parvathythilak/MIT-6.824
func TestAtMostOnce(t *testing.T) {
	runtime.GOMAXPROCS(4)

	tag := "csu"
	vshost := port(tag+"v", 1)
	vs := viewservice.StartServer(vshost)
	time.Sleep(time.Second)
	vck := viewservice.MakeClerk("", vshost)

	fmt.Printf("Test: at-most-once Put; unreliable ...\n")

	const nservers = 1
	var sa [nservers]*PBServer
	for i := 0; i < nservers; i++ {
		sa[i] = StartServer(vshost, port(tag, i+1))
		sa[i].unreliable = true
	}

	for iters := 0; iters < viewservice.DeadPings*2; iters++ {
		view, _ := vck.Get()
		if view.Primary != "" && view.Backup != "" {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}

	// give p+b time to ack, initialize
	time.Sleep(viewservice.PingInterval * viewservice.DeadPings)

	ck := MakeClerk(vshost, "")
	k := "counter"
	val := ""
	for i := 0; i < 100; i++ {
		v := strconv.Itoa(i)
		pv := ck.PutHash(k, v)
		if pv != val {
			fmt.Println(i)
			t.Fatalf("ck.Puthash() returned %v but expected %v\n", pv, val)
		}
		h := hash(val + v)
		val = strconv.Itoa(int(h))
	}

	v := ck.Get(k)
	if v != val {
		fmt.Println("101")
		t.Fatalf("ck.Get() returned %v but expected %v\n", v, val)
	}

	fmt.Printf("  ... Passed\n")

	for i := 0; i < nservers; i++ {
		sa[i].kill()
	}
	time.Sleep(time.Second)
	vs.Kill()
	time.Sleep(time.Second)
}
コード例 #9
0
ファイル: test_test.go プロジェクト: karanjude/mr
func TestAtMostOnce(t *testing.T) {
	runtime.GOMAXPROCS(4)

	tag := "tamo"
	vshost := port(tag+"v", 1)
	vs := viewservice.StartServer(vshost)
	time.Sleep(time.Second)
	vck := viewservice.MakeClerk("", vshost)

	fmt.Printf("Test: at-most-once Append; unreliable ...\n")

	const nservers = 1
	var sa [nservers]*PBServer
	for i := 0; i < nservers; i++ {
		sa[i] = StartServer(vshost, port(tag, i+1))
		sa[i].setunreliable(true)
	}

	for iters := 0; iters < viewservice.DeadPings*2; iters++ {
		view, _ := vck.Get()
		if view.Primary != "" && view.Backup != "" {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}

	view1, _ := vck.Get()

	// give p+b time to ack, initialize
	time.Sleep(viewservice.PingInterval * viewservice.DeadPings)

	view, _ := vck.Get()
	fmt.Println("->", view.Primary, view.Backup)
	fmt.Println("->", view1.Primary, view1.Backup)

	ck := MakeClerk(vshost, "")
	k := "counter"
	val := ""
	for i := 0; i < 100; i++ {
		v := strconv.Itoa(i)
		ck.Append(k, v)
		val = val + v
	}

	v := ck.Get(k)
	if v != val {
		t.Fatalf("ck.Get() returned %v but expected %v\n", v, val)
	}

	fmt.Printf("  ... Passed\n")

	for i := 0; i < nservers; i++ {
		sa[i].kill()
	}
	time.Sleep(time.Second)
	vs.Kill()
	time.Sleep(time.Second)
}
コード例 #10
0
ファイル: client.go プロジェクト: parvathythilak/MIT-6.824
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)

	ck.me = me
	ck.id = nrand()
	ck.seqNum = 0
	return ck
}
コード例 #11
0
ファイル: client.go プロジェクト: lmatz/Distributed-Systems
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here

	ck.currentView = viewservice.View{0, "", ""}
	ck.id = strconv.FormatInt(nrand(), 10)
	return ck
}
コード例 #12
0
ファイル: client.go プロジェクト: willx8/6.824lab
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.id = nrand() // For debug.
	ck.setNewPrimary()

	return ck
}
コード例 #13
0
ファイル: client.go プロジェクト: songgao/mit-ds-lab-2013
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	ok := false
	for !ok {
		ck.view, ok = ck.vs.Get()
		time.Sleep(viewservice.PingInterval)
	}
	return ck
}
コード例 #14
0
ファイル: client.go プロジェクト: gitter-badger/haze-kv
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.me = me
	ck.primary = ck.vs.Primary()
	ck.rpc_id = 1

	return ck
}
コード例 #15
0
ファイル: client.go プロジェクト: salibrandi/mexos
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)

	// Your ck.* initializations here
	view, _ := ck.vs.Ping(0)
	newPrimary := view.Primary
	ck.primary = newPrimary
	return ck
}
コード例 #16
0
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	// By Yan
	ck.curView.Primary = ""
	ck.curView.Backup = ""
	ck.curView.Viewnum = 0

	return ck
}
コード例 #17
0
ファイル: client.go プロジェクト: SunWeicheng0001/MIT6.824
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.view = viewservice.View{}

	// note: argument me could not garantuee unique, this ck.me field would be put along
	// with PutArgs to show client's identification
	ck.me = strconv.FormatInt(nrand(), 10)
	return ck
}
コード例 #18
0
ファイル: client.go プロジェクト: kennyhlam/6824
func MakeClerk(vshost string, me string) *Clerk {
  ck := new(Clerk)
  ck.vs = viewservice.MakeClerk(me, vshost)
  // Your ck.* initializations here

  ck.view = viewservice.View{}
  ck.xaction = 0
  ck.cid = nrand()

  return ck
}
コード例 #19
0
ファイル: client.go プロジェクト: amaliujia/MITDS6.824
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.client_view.Viewnum = 0
	ck.client_view.Primary = ""
	ck.client_view.Backup = ""

	ck.me = strconv.FormatInt(nrand(), 10)

	return ck
}
コード例 #20
0
ファイル: client.go プロジェクト: Narasimman/DS-MapReduce
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ok := false
	if !ok {
		ck.view, ok = ck.vs.Get()
		time.Sleep(viewservice.PingInterval)
	}

	return ck
}
コード例 #21
0
ファイル: client.go プロジェクト: aparnard/go-distsys-lib
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	//ck.currView,_ = ck.getView()
	ck.currView = viewservice.View{}
	//rand.Seed(time.Now().UTC().UnixNano())
	ck.ClientID = nrand()

	// Your ck.* initializations here

	return ck
}
コード例 #22
0
ファイル: client.go プロジェクト: bingtianbaihua/MITLab
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	// Your ck.* initializations here
	ck.primary = ck.vs.Primary()
	ck.rpcid = 1
	mu.Lock()
	defer mu.Unlock()
	ck.me = strconv.Itoa(clientNum)
	clientNum = clientNum + 1
	return ck
}
コード例 #23
0
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)

	// Your ck.* initializations here
	var success bool
	ck.view, success = ck.vs.Get()
	if !success {
		logger.Debug("ck.vs.Get failed")
	}

	return ck
}
コード例 #24
0
ファイル: client.go プロジェクト: sunshiming/6.824
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	ck.vshost = vshost
	//ck.Me = me
	ck.Me = strconv.FormatInt(nrand(), 10)

	ck.mu = &sync.Mutex{}

	view, _ := ck.vs.Get()
	ck.view = view
	ck.server = ck.view.Primary

	return ck
}
コード例 #25
0
ファイル: server.go プロジェクト: ctliu3/yds
func StartServer(vshost string, me string) *PBServer {
	pb := new(PBServer)
	pb.me = me
	pb.vs = viewservice.MakeClerk(me, vshost)
	pb.finish = make(chan interface{})
	// Your pb.* initializations here.
	pb.current = viewservice.View{Viewnum: 0}
	pb.db = make(map[string]string)
	//pb.filter = make(map[string]string)

	rpcs := rpc.NewServer()
	rpcs.Register(pb)

	os.Remove(pb.me)
	l, e := net.Listen("unix", pb.me)
	if e != nil {
		log.Fatal("listen error: ", e)
	}
	pb.l = l

	// please do not change any of the following code,
	// or do anything to subvert it.

	go func() {
		for pb.dead == false {
			conn, err := pb.l.Accept()
			if err == nil && pb.dead == false {
				if pb.unreliable && (rand.Int63()%1000) < 100 {
					// discard the request.
					conn.Close()
				} else if pb.unreliable && (rand.Int63()%1000) < 200 {
					// process the request but force discard of reply.
					c1 := conn.(*net.UnixConn)
					f, _ := c1.File()
					err := syscall.Shutdown(int(f.Fd()), syscall.SHUT_WR)
					if err != nil {
						fmt.Printf("shutdown: %v\n", err)
					}
					pb.done.Add(1)
					go func() {
						rpcs.ServeConn(conn)
						pb.done.Done()
					}()
				} else {
					pb.done.Add(1)
					go func() {
						rpcs.ServeConn(conn)
						pb.done.Done()
					}()
				}
			} else if err == nil {
				conn.Close()
			}
			if err != nil && pb.dead == false {
				fmt.Printf("PBServer(%v) accept: %v\n", me, err.Error())
				pb.kill()
			}
		}
		DPrintf("%s: wait until all request are done\n", pb.me)
		pb.done.Wait()
		// If you have an additional thread in your solution, you could
		// have it read to the finish channel to hear when to terminate.
		close(pb.finish)
	}()

	pb.done.Add(1)
	go func() {
		for pb.dead == false {
			pb.tick()
			time.Sleep(viewservice.PingInterval)
		}
		pb.done.Done()
	}()

	return pb
}
コード例 #26
0
ファイル: client.go プロジェクト: CyberZHG/Playground
func MakeClerk(vshost string, me string) *Clerk {
	ck := new(Clerk)
	ck.vs = viewservice.MakeClerk(me, vshost)
	ck.view = viewservice.View{}
	return ck
}
コード例 #27
0
ファイル: test_test.go プロジェクト: brandorondon/cs147-lab2
func TestPartition2(t *testing.T) {
	runtime.GOMAXPROCS(4)

	tag := "part2"
	vshost := port(tag+"v", 1)
	vs := viewservice.StartServer(vshost)
	time.Sleep(time.Second)
	vck := viewservice.MakeClerk("", vshost)

	ck1 := MakeClerk(vshost, "")

	vshosta := vshost + "a"
	os.Link(vshost, vshosta)

	s1 := StartServer(vshosta, port(tag, 1))
	delay := 0
	proxy(t, port(tag, 1), &delay)

	fmt.Printf("Test: Partitioned old primary does not complete Gets ...\n")

	deadtime := viewservice.PingInterval * viewservice.DeadPings
	time.Sleep(deadtime * 2)
	if vck.Primary() != s1.me {
		t.Fatal("primary never formed initial view")
	}

	s2 := StartServer(vshost, port(tag, 2))
	time.Sleep(deadtime * 2)
	v1, _ := vck.Get()
	if v1.Primary != s1.me || v1.Backup != s2.me {
		t.Fatal("backup did not join view")
	}

	ck1.Put("a", "1")
	check(ck1, "a", "1")

	os.Remove(vshosta)

	// start a client Get(), but use proxy to delay it long
	// enough that it won't reach s1 until after s1 is no
	// longer the primary.
	delay = 5
	stale_get := false
	go func() {
		x := ck1.Get("a")
		if x == "1" {
			stale_get = true
		}
	}()

	// now s1 cannot talk to viewserver, so view will change.

	for iter := 0; iter < viewservice.DeadPings*3; iter++ {
		if vck.Primary() == s2.me {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}
	if vck.Primary() != s2.me {
		t.Fatalf("primary never changed")
	}

	s3 := StartServer(vshost, port(tag, 3))
	for iter := 0; iter < viewservice.DeadPings*3; iter++ {
		v, _ := vck.Get()
		if v.Backup == s3.me && v.Primary == s2.me {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}
	v2, _ := vck.Get()
	if v2.Primary != s2.me || v2.Backup != s3.me {
		t.Fatalf("new backup never joined")
	}
	time.Sleep(2 * time.Second)

	ck2 := MakeClerk(vshost, "")
	ck2.Put("a", "2")
	check(ck2, "a", "2")

	s2.kill()

	// wait for delayed get to s1 to complete.
	time.Sleep(6 * time.Second)

	if stale_get == true {
		t.Fatalf("partitioned primary replied to a Get with a stale value")
	}

	check(ck2, "a", "2")

	fmt.Printf("  ... Passed\n")

	s1.kill()
	s2.kill()
	s3.kill()
	vs.Kill()
}
コード例 #28
0
ファイル: test_test.go プロジェクト: brandorondon/cs147-lab2
func TestPartition1(t *testing.T) {
	runtime.GOMAXPROCS(4)

	tag := "part1"
	vshost := port(tag+"v", 1)
	vs := viewservice.StartServer(vshost)
	time.Sleep(time.Second)
	vck := viewservice.MakeClerk("", vshost)

	ck1 := MakeClerk(vshost, "")

	fmt.Printf("Test: Old primary does not serve Gets ...\n")

	vshosta := vshost + "a"
	os.Link(vshost, vshosta)

	s1 := StartServer(vshosta, port(tag, 1))
	delay := 0
	proxy(t, port(tag, 1), &delay)

	deadtime := viewservice.PingInterval * viewservice.DeadPings
	time.Sleep(deadtime * 2)
	if vck.Primary() != s1.me {
		t.Fatal("primary never formed initial view")
	}

	s2 := StartServer(vshost, port(tag, 2))
	time.Sleep(deadtime * 2)
	v1, _ := vck.Get()
	if v1.Primary != s1.me || v1.Backup != s2.me {
		t.Fatal("backup did not join view")
	}

	ck1.Put("a", "1")
	check(ck1, "a", "1")

	os.Remove(vshosta)

	// start a client Get(), but use proxy to delay it long
	// enough that it won't reach s1 until after s1 is no
	// longer the primary.
	delay = 4
	stale_get := false
	go func() {
		x := ck1.Get("a")
		if x == "1" {
			stale_get = true
		}
	}()

	// now s1 cannot talk to viewserver, so view will change,
	// and s1 won't immediately realize.

	for iter := 0; iter < viewservice.DeadPings*3; iter++ {
		if vck.Primary() == s2.me {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}
	if vck.Primary() != s2.me {
		t.Fatalf("primary never changed")
	}

	// wait long enough that s2 is guaranteed to have Pinged
	// the viewservice, and thus that s2 must know about
	// the new view.
	time.Sleep(2 * viewservice.PingInterval)

	// change the value (on s2) so it's no longer "1".
	ck2 := MakeClerk(vshost, "")
	ck2.Put("a", "111")
	check(ck2, "a", "111")

	// wait for the background Get to s1 to be delivered.
	time.Sleep(5 * time.Second)
	if stale_get {
		t.Fatalf("Get to old primary succeeded and produced stale value")
	}

	check(ck2, "a", "111")

	fmt.Printf("  ... Passed\n")

	s1.kill()
	s2.kill()
	vs.Kill()
}
コード例 #29
0
ファイル: test_test.go プロジェクト: brandorondon/cs147-lab2
func TestRepeatedCrashUnreliable(t *testing.T) {
	runtime.GOMAXPROCS(4)

	tag := "rcu"
	vshost := port(tag+"v", 1)
	vs := viewservice.StartServer(vshost)
	time.Sleep(time.Second)
	vck := viewservice.MakeClerk("", vshost)

	fmt.Printf("Test: Repeated failures/restarts; unreliable ...\n")

	const nservers = 3
	var sa [nservers]*PBServer
	for i := 0; i < nservers; i++ {
		sa[i] = StartServer(vshost, port(tag, i+1))
		sa[i].unreliable = true
	}

	for i := 0; i < viewservice.DeadPings; i++ {
		v, _ := vck.Get()
		if v.Primary != "" && v.Backup != "" {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}

	// wait a bit for primary to initialize backup
	time.Sleep(viewservice.DeadPings * viewservice.PingInterval)

	done := false

	go func() {
		// kill and restart servers
		rr := rand.New(rand.NewSource(int64(os.Getpid())))
		for done == false {
			i := rr.Int() % nservers
			// fmt.Printf("%v killing %v\n", ts(), 5001+i)
			sa[i].kill()

			// wait long enough for new view to form, backup to be initialized
			time.Sleep(2 * viewservice.PingInterval * viewservice.DeadPings)

			sa[i] = StartServer(vshost, port(tag, i+1))

			// wait long enough for new view to form, backup to be initialized
			time.Sleep(2 * viewservice.PingInterval * viewservice.DeadPings)
		}
	}()

	const nth = 2
	var cha [nth]chan bool
	for xi := 0; xi < nth; xi++ {
		cha[xi] = make(chan bool)
		go func(i int) {
			ok := false
			defer func() { cha[i] <- ok }()
			ck := MakeClerk(vshost, "")
			data := map[string]string{}
			rr := rand.New(rand.NewSource(int64(os.Getpid() + i)))
			for done == false {
				k := strconv.Itoa((i * 1000000) + (rr.Int() % 10))
				wanted, ok := data[k]
				if ok {
					v := ck.Get(k)
					if v != wanted {
						t.Fatalf("key=%v wanted=%v got=%v", k, wanted, v)
					}
				}
				nv := strconv.Itoa(rr.Int())
				ck.Put(k, nv)
				data[k] = nv
				// if no sleep here, then server tick() threads do not get
				// enough time to Ping the viewserver.
				time.Sleep(10 * time.Millisecond)
			}
			ok = true
		}(xi)
	}

	time.Sleep(20 * time.Second)
	done = true

	for i := 0; i < nth; i++ {
		ok := <-cha[i]
		if ok == false {
			t.Fatal("child failed")
		}
	}

	ck := MakeClerk(vshost, "")
	ck.Put("aaa", "bbb")
	if v := ck.Get("aaa"); v != "bbb" {
		t.Fatalf("final Put/Get failed")
	}

	fmt.Printf("  ... Passed\n")

	for i := 0; i < nservers; i++ {
		sa[i].kill()
	}
	time.Sleep(time.Second)
	vs.Kill()
	time.Sleep(time.Second)
}
コード例 #30
0
ファイル: test_test.go プロジェクト: brandorondon/cs147-lab2
func TestConcurrentSameUnreliable(t *testing.T) {
	runtime.GOMAXPROCS(4)

	tag := "csu"
	vshost := port(tag+"v", 1)
	vs := viewservice.StartServer(vshost)
	time.Sleep(time.Second)
	vck := viewservice.MakeClerk("", vshost)

	fmt.Printf("Test: Concurrent Put()s to the same key; unreliable ...\n")

	const nservers = 2
	var sa [nservers]*PBServer
	for i := 0; i < nservers; i++ {
		sa[i] = StartServer(vshost, port(tag, i+1))
		sa[i].unreliable = true
	}

	for iters := 0; iters < viewservice.DeadPings*2; iters++ {
		view, _ := vck.Get()
		if view.Primary != "" && view.Backup != "" {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}

	// give p+b time to ack, initialize
	time.Sleep(viewservice.PingInterval * viewservice.DeadPings)

	done := false

	view1, _ := vck.Get()
	const nclients = 3
	const nkeys = 2
	for xi := 0; xi < nclients; xi++ {
		go func(i int) {
			ck := MakeClerk(vshost, "")
			rr := rand.New(rand.NewSource(int64(os.Getpid() + i)))
			for done == false {
				k := strconv.Itoa(rr.Int() % nkeys)
				v := strconv.Itoa(rr.Int())
				ck.Put(k, v)
			}
		}(xi)
	}

	time.Sleep(5 * time.Second)
	done = true
	time.Sleep(time.Second)

	// read from primary
	ck := MakeClerk(vshost, "")
	var vals [nkeys]string
	for i := 0; i < nkeys; i++ {
		vals[i] = ck.Get(strconv.Itoa(i))
		if vals[i] == "" {
			t.Fatalf("Get(%v) failed from primary", i)
		}
	}

	// kill the primary
	for i := 0; i < nservers; i++ {
		if view1.Primary == sa[i].me {
			sa[i].kill()
			break
		}
	}
	for iters := 0; iters < viewservice.DeadPings*2; iters++ {
		view, _ := vck.Get()
		if view.Primary == view1.Backup {
			break
		}
		time.Sleep(viewservice.PingInterval)
	}
	view2, _ := vck.Get()
	if view2.Primary != view1.Backup {
		t.Fatal("wrong Primary")
	}

	// read from old backup
	for i := 0; i < nkeys; i++ {
		z := ck.Get(strconv.Itoa(i))
		if z != vals[i] {
			t.Fatalf("Get(%v) from backup; wanted %v, got %v", i, vals[i], z)
		}
	}

	fmt.Printf("  ... Passed\n")

	for i := 0; i < nservers; i++ {
		sa[i].kill()
	}
	time.Sleep(time.Second)
	vs.Kill()
	time.Sleep(time.Second)
}