func testRaftRestartCluster(t *testing.T, stagger bool) {
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Propose a value
	values := make([]*api.Node, 2)
	var err error
	values[0], err = raftutils.ProposeValue(t, nodes[1], "id1")
	assert.NoError(t, err, "failed to propose value")

	// Stop all nodes
	for _, node := range nodes {
		node.Server.Stop()
		node.Shutdown()
	}

	raftutils.AdvanceTicks(clockSource, 5)

	// Restart all nodes
	i := 0
	for k, node := range nodes {
		if stagger && i != 0 {
			raftutils.AdvanceTicks(clockSource, 1)
		}
		nodes[k] = raftutils.RestartNode(t, clockSource, node, false)
		i++
	}
	raftutils.WaitForCluster(t, clockSource, nodes)

	// Propose another value
	values[1], err = raftutils.ProposeValue(t, raftutils.Leader(nodes), "id2")
	assert.NoError(t, err, "failed to propose value")

	for _, node := range nodes {
		assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
			var err error
			node.MemoryStore().View(func(tx store.ReadTx) {
				var allNodes []*api.Node
				allNodes, err = store.FindNodes(tx, store.All)
				if err != nil {
					return
				}
				if len(allNodes) != 2 {
					err = fmt.Errorf("expected 2 nodes, got %d", len(allNodes))
					return
				}

				for i, nodeID := range []string{"id1", "id2"} {
					n := store.GetNode(tx, nodeID)
					if !reflect.DeepEqual(n, values[i]) {
						err = fmt.Errorf("node %s did not match expected value", nodeID)
						return
					}
				}
			})
			return err
		}))
	}
}

func TestRaftQuorumRecovery(t *testing.T) {
	t.Parallel()

	// Bring up a 5 nodes cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Lose a majority
	for i := uint64(1); i <= 3; i++ {
		nodes[i].Server.Stop()
		nodes[i].Shutdown()
	}

	raftutils.AdvanceTicks(clockSource, 5)

	// Restore the majority by restarting node 3
	nodes[3] = raftutils.RestartNode(t, clockSource, nodes[3], false)

	delete(nodes, 1)
	delete(nodes, 2)
	raftutils.WaitForCluster(t, clockSource, nodes)

	// Propose a value
	value, err := raftutils.ProposeValue(t, raftutils.Leader(nodes))
	assert.NoError(t, err)

	for _, node := range nodes {
		raftutils.CheckValue(t, clockSource, node, value)
	}
}

// This test rotates the encryption key and restarts the node - the intent is try to trigger
// race conditions if there is more than one node and hence consensus may take longer.
func TestRaftEncryptionKeyRotationStress(t *testing.T) {
	t.Parallel()

	// Bring up a 3 nodes cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)
	leader := nodes[1]

	// constantly propose values
	done, stop, restart, clusterReady := make(chan struct{}), make(chan struct{}), make(chan struct{}), make(chan struct{})
	go func() {
		counter := len(nodes)
		for {
			select {
			case <-stop:
				close(done)
				return
			case <-restart:
				// the node restarts may trigger a leadership change, so wait until the cluster has 3
				// nodes again and a leader is selected before proposing more values
				<-clusterReady
				leader = raftutils.Leader(nodes)
			default:
				counter += 1
				raftutils.ProposeValue(t, leader, DefaultProposalTime, fmt.Sprintf("id%d", counter))
			}
		}
	}()

	for i := 0; i < 30; i++ {
		// rotate the encryption key
		nodes[3].KeyRotator.QueuePendingKey([]byte(fmt.Sprintf("newKey%d", i)))
		nodes[3].KeyRotator.RotationNotify() <- struct{}{}

		require.NoError(t, raftutils.PollFunc(clockSource, func() error {
			if nodes[3].KeyRotator.GetKeys().PendingDEK == nil {
				return nil
			}
			return fmt.Errorf("not done rotating yet")
		}))

		// restart the node and wait for everything to settle and a leader to be elected
		nodes[3].Server.Stop()
		nodes[3].ShutdownRaft()
		restart <- struct{}{}
		nodes[3] = raftutils.RestartNode(t, clockSource, nodes[3], false)
		raftutils.AdvanceTicks(clockSource, 1)

		raftutils.WaitForCluster(t, clockSource, nodes)
		clusterReady <- struct{}{}
	}

	close(stop)
	<-done
}

func TestRaftLeaderDown(t *testing.T) {
	t.Parallel()

	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Stop node 1
	nodes[1].Stop()

	newCluster := map[uint64]*raftutils.TestNode{
		2: nodes[2],
		3: nodes[3],
	}
	// Wait for the re-election to occur
	raftutils.WaitForCluster(t, clockSource, newCluster)

	// Leader should not be 1
	assert.NotEqual(t, nodes[2].Leader(), nodes[1].Config.ID)

	// Ensure that node 2 and node 3 have the same leader
	assert.Equal(t, nodes[3].Leader(), nodes[2].Leader())

	// Find the leader node and a follower node
	var (
		leaderNode   *raftutils.TestNode
		followerNode *raftutils.TestNode
	)
	for i, n := range newCluster {
		if n.Config.ID == n.Leader() {
			leaderNode = n
			if i == 2 {
				followerNode = newCluster[3]
			} else {
				followerNode = newCluster[2]
			}
		}
	}

	require.NotNil(t, leaderNode)
	require.NotNil(t, followerNode)

	// Propose a value
	value, err := raftutils.ProposeValue(t, leaderNode)
	assert.NoError(t, err, "failed to propose value")

	// The value should be replicated on all remaining nodes
	raftutils.CheckValue(t, clockSource, leaderNode, value)
	assert.Equal(t, len(leaderNode.GetMemberlist()), 3)

	raftutils.CheckValue(t, clockSource, followerNode, value)
	assert.Equal(t, len(followerNode.GetMemberlist()), 3)
}

func TestRaftRejoin(t *testing.T) {
	t.Parallel()

	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	ids := []string{"id1", "id2"}

	// Propose a value
	values := make([]*api.Node, 2)
	var err error
	values[0], err = raftutils.ProposeValue(t, nodes[1], ids[0])
	assert.NoError(t, err, "failed to propose value")

	// The value should be replicated on node 3
	raftutils.CheckValue(t, clockSource, nodes[3], values[0])
	assert.Equal(t, len(nodes[3].GetMemberlist()), 3)

	// Stop node 3
	nodes[3].Server.Stop()
	nodes[3].Shutdown()

	// Propose another value
	values[1], err = raftutils.ProposeValue(t, nodes[1], ids[1])
	assert.NoError(t, err, "failed to propose value")

	// Nodes 1 and 2 should have the new value
	raftutils.CheckValuesOnNodes(t, clockSource, map[uint64]*raftutils.TestNode{1: nodes[1], 2: nodes[2]}, ids, values)

	nodes[3] = raftutils.RestartNode(t, clockSource, nodes[3], false)
	raftutils.WaitForCluster(t, clockSource, nodes)

	// Node 3 should have all values, including the one proposed while
	// it was unavailable.
	raftutils.CheckValuesOnNodes(t, clockSource, nodes, ids, values)
}

func TestRaftLogReplication(t *testing.T) {
	t.Parallel()

	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Propose a value
	value, err := raftutils.ProposeValue(t, nodes[1])
	assert.NoError(t, err, "failed to propose value")

	// All nodes should have the value in the physical store
	raftutils.CheckValue(t, clockSource, nodes[1], value)
	raftutils.CheckValue(t, clockSource, nodes[2], value)
	raftutils.CheckValue(t, clockSource, nodes[3], value)
}

func TestRaftUnreachableNode(t *testing.T) {
	t.Parallel()

	nodes := make(map[uint64]*raftutils.TestNode)
	var clockSource *fakeclock.FakeClock
	nodes[1], clockSource = raftutils.NewInitNode(t, tc, nil)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	// Add a new node
	nodes[2] = raftutils.NewNode(t, clockSource, tc, raft.NodeOptions{JoinAddr: nodes[1].Address})

	err := nodes[2].JoinAndStart(ctx)
	require.NoError(t, err, "can't join cluster")

	go nodes[2].Run(ctx)

	// Stop the Raft server of second node on purpose after joining
	nodes[2].Server.Stop()
	nodes[2].Listener.Close()

	raftutils.AdvanceTicks(clockSource, 5)
	time.Sleep(100 * time.Millisecond)

	wrappedListener := raftutils.RecycleWrappedListener(nodes[2].Listener)
	securityConfig := nodes[2].SecurityConfig
	serverOpts := []grpc.ServerOption{grpc.Creds(securityConfig.ServerTLSCreds)}
	s := grpc.NewServer(serverOpts...)

	nodes[2].Server = s
	raft.Register(s, nodes[2].Node)

	go func() {
		// After stopping, we should receive an error from Serve
		assert.Error(t, s.Serve(wrappedListener))
	}()

	raftutils.WaitForCluster(t, clockSource, nodes)
	defer raftutils.TeardownCluster(t, nodes)

	// Propose a value
	value, err := raftutils.ProposeValue(t, nodes[1], DefaultProposalTime)
	assert.NoError(t, err, "failed to propose value")

	// All nodes should have the value in the physical store
	raftutils.CheckValue(t, clockSource, nodes[1], value)
	raftutils.CheckValue(t, clockSource, nodes[2], value)
}

func TestRaftLogReplicationWithoutLeader(t *testing.T) {
	t.Parallel()
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Stop the leader
	nodes[1].Stop()

	// Propose a value
	_, err := raftutils.ProposeValue(t, nodes[2])
	assert.Error(t, err)

	// No value should be replicated in the store in the absence of the leader
	raftutils.CheckNoValue(t, clockSource, nodes[2])
	raftutils.CheckNoValue(t, clockSource, nodes[3])
}

func TestRaftFollowerLeave(t *testing.T) {
	t.Parallel()

	// Bring up a 5 nodes cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Node 5 leaves the cluster
	// Use gRPC instead of calling handler directly because of
	// authorization check.
	cc, err := dial(nodes[1], nodes[1].Address)
	assert.NoError(t, err)
	raftClient := api.NewRaftMembershipClient(cc)
	defer cc.Close()
	ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
	resp, err := raftClient.Leave(ctx, &api.LeaveRequest{Node: &api.RaftMember{RaftID: nodes[5].Config.ID}})
	assert.NoError(t, err, "error sending message to leave the raft")
	assert.NotNil(t, resp, "leave response message is nil")

	raftutils.ShutdownNode(nodes[5])
	delete(nodes, 5)

	raftutils.WaitForPeerNumber(t, clockSource, nodes, 4)

	// Propose a value
	value, err := raftutils.ProposeValue(t, nodes[1], DefaultProposalTime)
	assert.NoError(t, err, "failed to propose value")

	// Value should be replicated on every node
	raftutils.CheckValue(t, clockSource, nodes[1], value)
	assert.Len(t, nodes[1].GetMemberlist(), 4)

	raftutils.CheckValue(t, clockSource, nodes[2], value)
	assert.Len(t, nodes[2].GetMemberlist(), 4)

	raftutils.CheckValue(t, clockSource, nodes[3], value)
	assert.Len(t, nodes[3].GetMemberlist(), 4)

	raftutils.CheckValue(t, clockSource, nodes[4], value)
	assert.Len(t, nodes[4].GetMemberlist(), 4)
}

func TestRaftNewNodeGetsData(t *testing.T) {
	t.Parallel()

	// Bring up a 3 node cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Propose a value
	value, err := raftutils.ProposeValue(t, nodes[1])
	assert.NoError(t, err, "failed to propose value")

	// Add a new node
	raftutils.AddRaftNode(t, clockSource, nodes, tc)

	time.Sleep(500 * time.Millisecond)

	// Value should be replicated on every node
	for _, node := range nodes {
		raftutils.CheckValue(t, clockSource, node, value)
		assert.Equal(t, len(node.GetMemberlist()), 4)
	}
}

func TestRaftQuorumFailure(t *testing.T) {
	t.Parallel()

	// Bring up a 5 nodes cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Lose a majority
	for i := uint64(3); i <= 5; i++ {
		nodes[i].Server.Stop()
		nodes[i].Stop()
	}

	// Propose a value
	_, err := raftutils.ProposeValue(t, nodes[1])
	assert.Error(t, err)

	// The value should not be replicated, we have no majority
	raftutils.CheckNoValue(t, clockSource, nodes[2])
	raftutils.CheckNoValue(t, clockSource, nodes[1])
}

func TestRaftUnreachableNode(t *testing.T) {
	t.Parallel()

	nodes := make(map[uint64]*raftutils.TestNode)
	var clockSource *fakeclock.FakeClock
	nodes[1], clockSource = raftutils.NewInitNode(t, tc, nil)

	ctx := context.Background()
	// Add a new node, but don't start its server yet
	n := raftutils.NewNode(t, clockSource, tc, raft.NewNodeOptions{JoinAddr: nodes[1].Address})
	go n.Run(ctx)

	raftutils.AdvanceTicks(clockSource, 5)
	time.Sleep(100 * time.Millisecond)

	raft.Register(n.Server, n.Node)

	// Now start the new node's server
	go func() {
		// After stopping, we should receive an error from Serve
		assert.Error(t, n.Server.Serve(n.Listener))
	}()

	nodes[2] = n
	raftutils.WaitForCluster(t, clockSource, nodes)

	defer raftutils.TeardownCluster(t, nodes)

	// Propose a value
	value, err := raftutils.ProposeValue(t, nodes[1])
	assert.NoError(t, err, "failed to propose value")

	// All nodes should have the value in the physical store
	raftutils.CheckValue(t, clockSource, nodes[1], value)
	raftutils.CheckValue(t, clockSource, nodes[2], value)
}

func TestRaftFollowerDown(t *testing.T) {
	t.Parallel()

	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// Stop node 3
	nodes[3].Stop()

	// Leader should still be 1
	assert.True(t, nodes[1].IsLeader(), "node 1 is not a leader anymore")
	assert.Equal(t, nodes[2].Leader(), nodes[1].Config.ID)

	// Propose a value
	value, err := raftutils.ProposeValue(t, nodes[1])
	assert.NoError(t, err, "failed to propose value")

	// The value should be replicated on all remaining nodes
	raftutils.CheckValue(t, clockSource, nodes[1], value)
	assert.Equal(t, len(nodes[1].GetMemberlist()), 3)

	raftutils.CheckValue(t, clockSource, nodes[2], value)
	assert.Equal(t, len(nodes[2].GetMemberlist()), 3)
}

func TestRaftForceNewCluster(t *testing.T) {
	t.Parallel()

	nodes, clockSource := raftutils.NewRaftCluster(t, tc)

	// Propose a value
	values := make([]*api.Node, 2)
	var err error
	values[0], err = raftutils.ProposeValue(t, nodes[1], "id1")
	assert.NoError(t, err, "failed to propose value")

	// The memberlist should contain 3 members on each node
	for i := 1; i <= 3; i++ {
		assert.Equal(t, len(nodes[uint64(i)].GetMemberlist()), 3)
	}

	// Stop all nodes
	for _, node := range nodes {
		node.Server.Stop()
		node.Shutdown()
	}

	raftutils.AdvanceTicks(clockSource, 5)

	toClean := map[uint64]*raftutils.TestNode{
		2: nodes[2],
		3: nodes[3],
	}
	raftutils.TeardownCluster(t, toClean)
	delete(nodes, 2)
	delete(nodes, 3)

	// Only restart the first node with force-new-cluster option
	nodes[1] = raftutils.RestartNode(t, clockSource, nodes[1], true)
	raftutils.WaitForCluster(t, clockSource, nodes)

	// The memberlist should contain only one node (self)
	assert.Equal(t, len(nodes[1].GetMemberlist()), 1)

	// Add 2 more members
	nodes[2] = raftutils.NewJoinNode(t, clockSource, nodes[1].Address, tc)
	raftutils.WaitForCluster(t, clockSource, nodes)

	nodes[3] = raftutils.NewJoinNode(t, clockSource, nodes[1].Address, tc)
	raftutils.WaitForCluster(t, clockSource, nodes)

	newCluster := map[uint64]*raftutils.TestNode{
		1: nodes[1],
		2: nodes[2],
		3: nodes[3],
	}
	defer raftutils.TeardownCluster(t, newCluster)

	// The memberlist should contain 3 members on each node
	for i := 1; i <= 3; i++ {
		assert.Equal(t, len(nodes[uint64(i)].GetMemberlist()), 3)
	}

	// Propose another value
	values[1], err = raftutils.ProposeValue(t, raftutils.Leader(nodes), "id2")
	assert.NoError(t, err, "failed to propose value")

	for _, node := range nodes {
		assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
			var err error
			node.MemoryStore().View(func(tx store.ReadTx) {
				var allNodes []*api.Node
				allNodes, err = store.FindNodes(tx, store.All)
				if err != nil {
					return
				}
				if len(allNodes) != 2 {
					err = fmt.Errorf("expected 2 nodes, got %d", len(allNodes))
					return
				}

				for i, nodeID := range []string{"id1", "id2"} {
					n := store.GetNode(tx, nodeID)
					if !reflect.DeepEqual(n, values[i]) {
						err = fmt.Errorf("node %s did not match expected value", nodeID)
						return
					}
				}
			})
			return err
		}))
	}
}

// This test rotates the encryption key and waits for the expected thing to happen
func TestRaftEncryptionKeyRotationWait(t *testing.T) {
	t.Parallel()
	nodes := make(map[uint64]*raftutils.TestNode)
	var clockSource *fakeclock.FakeClock

	raftConfig := raft.DefaultRaftConfig()
	nodes[1], clockSource = raftutils.NewInitNode(t, tc, &raftConfig)
	defer raftutils.TeardownCluster(t, nodes)

	nodeIDs := []string{"id1", "id2", "id3"}
	values := make([]*api.Node, len(nodeIDs))

	// Propose 3 values
	var err error
	for i, nodeID := range nodeIDs[:3] {
		values[i], err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeID)
		require.NoError(t, err, "failed to propose value")
	}

	snapDir := filepath.Join(nodes[1].StateDir, "snap-v3-encrypted")

	startingKeys := nodes[1].KeyRotator.GetKeys()

	// rotate the encryption key
	nodes[1].KeyRotator.QueuePendingKey([]byte("key2"))
	nodes[1].KeyRotator.RotationNotify() <- struct{}{}

	// the rotation should trigger a snapshot, which should notify the rotator when it's done
	require.NoError(t, raftutils.PollFunc(clockSource, func() error {
		snapshots, err := storage.ListSnapshots(snapDir)
		if err != nil {
			return err
		}
		if len(snapshots) != 1 {
			return fmt.Errorf("expected 1 snapshot, found %d on new node", len(snapshots))
		}
		if nodes[1].KeyRotator.NeedsRotation() {
			return fmt.Errorf("rotation never finished")
		}
		return nil
	}))
	raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)

	// Propose a 4th value
	nodeIDs = append(nodeIDs, "id4")
	v, err := raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, "id4")
	require.NoError(t, err, "failed to propose value")
	values = append(values, v)
	raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)

	nodes[1].Server.Stop()
	nodes[1].ShutdownRaft()

	// Try to restart node 1. Without the new unlock key, it can't actually start
	n, ctx := raftutils.CopyNode(t, clockSource, nodes[1], false, raftutils.NewSimpleKeyRotator(startingKeys))
	require.Error(t, n.Node.JoinAndStart(ctx),
		"should not have been able to restart since we can't read snapshots")

	// with the right key, it can start, even if the right key is only the pending key
	newKeys := startingKeys
	newKeys.PendingDEK = []byte("key2")
	nodes[1].KeyRotator = raftutils.NewSimpleKeyRotator(newKeys)
	nodes[1] = raftutils.RestartNode(t, clockSource, nodes[1], false)

	raftutils.WaitForCluster(t, clockSource, nodes)

	// as soon as we joined, it should have finished rotating the key
	require.False(t, nodes[1].KeyRotator.NeedsRotation())
	raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)

	// break snapshotting, and ensure that key rotation never finishes
	tempSnapDir := filepath.Join(nodes[1].StateDir, "snap-backup")
	require.NoError(t, os.Rename(snapDir, tempSnapDir))
	require.NoError(t, ioutil.WriteFile(snapDir, []byte("this is no longer a directory"), 0644))

	nodes[1].KeyRotator.QueuePendingKey([]byte("key3"))
	nodes[1].KeyRotator.RotationNotify() <- struct{}{}

	time.Sleep(250 * time.Millisecond)

	// rotation has not been finished, because we cannot take a snapshot
	require.True(t, nodes[1].KeyRotator.NeedsRotation())

	// Propose a 5th value, so we have WALs written with the new key
	nodeIDs = append(nodeIDs, "id5")
	v, err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, "id5")
	require.NoError(t, err, "failed to propose value")
	values = append(values, v)
	raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)

	nodes[1].Server.Stop()
	nodes[1].ShutdownRaft()

	// restore the snapshot dir
	require.NoError(t, os.RemoveAll(snapDir))
	require.NoError(t, os.Rename(tempSnapDir, snapDir))

	// Now the wals are a mix of key2 and key3 - we can't actually start with either key
	singleKey := raft.EncryptionKeys{CurrentDEK: []byte("key2")}
//.........这里部分代码省略.........

func TestRaftLeaderLeave(t *testing.T) {
	t.Parallel()

	nodes, clockSource := raftutils.NewRaftCluster(t, tc)

	// node 1 is the leader
	assert.Equal(t, nodes[1].Leader(), nodes[1].Config.ID)

	// Try to leave the raft
	// Use gRPC instead of calling handler directly because of
	// authorization check.
	client, err := nodes[1].ConnectToMember(nodes[1].Address, 10*time.Second)
	assert.NoError(t, err)
	defer client.Conn.Close()
	raftClient := api.NewRaftMembershipClient(client.Conn)
	ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
	resp, err := raftClient.Leave(ctx, &api.LeaveRequest{Node: &api.RaftMember{RaftID: nodes[1].Config.ID}})
	assert.NoError(t, err, "error sending message to leave the raft")
	assert.NotNil(t, resp, "leave response message is nil")

	newCluster := map[uint64]*raftutils.TestNode{
		2: nodes[2],
		3: nodes[3],
	}
	// Wait for election tick
	raftutils.WaitForCluster(t, clockSource, newCluster)

	// Leader should not be 1
	assert.NotEqual(t, nodes[2].Leader(), nodes[1].Config.ID)
	assert.Equal(t, nodes[2].Leader(), nodes[3].Leader())

	leader := nodes[2].Leader()

	// Find the leader node and a follower node
	var (
		leaderNode   *raftutils.TestNode
		followerNode *raftutils.TestNode
	)
	for i, n := range nodes {
		if n.Config.ID == leader {
			leaderNode = n
			if i == 2 {
				followerNode = nodes[3]
			} else {
				followerNode = nodes[2]
			}
		}
	}

	require.NotNil(t, leaderNode)
	require.NotNil(t, followerNode)

	// Propose a value
	value, err := raftutils.ProposeValue(t, leaderNode)
	assert.NoError(t, err, "failed to propose value")

	// The value should be replicated on all remaining nodes
	raftutils.CheckValue(t, clockSource, leaderNode, value)
	assert.Equal(t, len(leaderNode.GetMemberlist()), 2)

	raftutils.CheckValue(t, clockSource, followerNode, value)
	assert.Equal(t, len(followerNode.GetMemberlist()), 2)

	raftutils.TeardownCluster(t, newCluster)
}

func TestStress(t *testing.T) {
	t.Parallel()

	// Bring up a 5 nodes cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	raftutils.AddRaftNode(t, clockSource, nodes, tc)
	defer raftutils.TeardownCluster(t, nodes)

	// number of nodes that are running
	nup := len(nodes)
	// record of nodes that are down
	idleNodes := map[int]struct{}{}
	// record of ids that proposed successfully or time-out
	pIDs := []string{}

	leader := -1
	for iters := 0; iters < 1000; iters++ {
		// keep proposing new values and killing leader
		for i := 1; i <= 5; i++ {
			if nodes[uint64(i)] != nil {
				id := strconv.Itoa(iters)
				_, err := raftutils.ProposeValue(t, nodes[uint64(i)], id)

				if err == nil {
					pIDs = append(pIDs, id)
					// if propose successfully, at least there are 3 running nodes
					assert.True(t, nup >= 3)
					// only leader can propose value
					assert.True(t, leader == i || leader == -1)
					// update leader
					leader = i
					break
				} else if strings.Contains(err.Error(), "context deadline exceeded") {
					// though it's timing out, we still record this value
					// for it may be proposed successfully and stored in Raft some time later
					pIDs = append(pIDs, id)
				}
			}
		}

		if rand.Intn(100) < 10 {
			// increase clock to make potential election finish quickly
			clockSource.Increment(200 * time.Millisecond)
			time.Sleep(10 * time.Millisecond)
		} else {
			ms := rand.Intn(10)
			clockSource.Increment(time.Duration(ms) * time.Millisecond)
		}

		if leader != -1 {
			// if propose successfully, try to kill a node in random
			s := rand.Intn(5) + 1
			if _, ok := idleNodes[s]; !ok {
				id := uint64(s)
				nodes[id].Server.Stop()
				nodes[id].Shutdown()
				idleNodes[s] = struct{}{}
				nup -= 1
				if s == leader {
					// leader is killed
					leader = -1
				}
			}
		}

		if nup < 3 {
			// if quorum is lost, try to bring back a node
			s := rand.Intn(5) + 1
			if _, ok := idleNodes[s]; ok {
				id := uint64(s)
				nodes[id] = raftutils.RestartNode(t, clockSource, nodes[id], false)
				delete(idleNodes, s)
				nup++
			}
		}
	}

	// bring back all nodes and propose the final value
	for i := range idleNodes {
		id := uint64(i)
		nodes[id] = raftutils.RestartNode(t, clockSource, nodes[id], false)
	}
	raftutils.WaitForCluster(t, clockSource, nodes)
	id := strconv.Itoa(1000)
	val, err := raftutils.ProposeValue(t, raftutils.Leader(nodes), id)
	assert.NoError(t, err, "failed to propose value")
	pIDs = append(pIDs, id)

	// increase clock to make cluster stable
	time.Sleep(500 * time.Millisecond)
	clockSource.Increment(500 * time.Millisecond)

	ids, values := raftutils.GetAllValuesOnNode(t, clockSource, nodes[1])

	// since cluster is stable, final value must be in the raft store
	find := false
	for _, value := range values {
		if reflect.DeepEqual(value, val) {
			find = true
//.........这里部分代码省略.........

func TestRaftSnapshotForceNewCluster(t *testing.T) {
	t.Parallel()

	// Bring up a 3 node cluster
	nodes, clockSource := raftutils.NewRaftCluster(t, tc, &api.RaftConfig{SnapshotInterval: 10, LogEntriesForSlowFollowers: 0})
	defer raftutils.TeardownCluster(t, nodes)

	nodeIDs := []string{"id1", "id2", "id3", "id4", "id5"}

	// Propose 3 values.
	for _, nodeID := range nodeIDs[:3] {
		_, err := raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeID)
		assert.NoError(t, err, "failed to propose value")
	}

	// Remove one of the original nodes

	// Use gRPC instead of calling handler directly because of
	// authorization check.
	cc, err := dial(nodes[1], nodes[1].Address)
	assert.NoError(t, err)
	raftClient := api.NewRaftMembershipClient(cc)
	defer cc.Close()
	ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
	resp, err := raftClient.Leave(ctx, &api.LeaveRequest{Node: &api.RaftMember{RaftID: nodes[2].Config.ID}})
	assert.NoError(t, err, "error sending message to leave the raft")
	assert.NotNil(t, resp, "leave response message is nil")

	raftutils.ShutdownNode(nodes[2])
	delete(nodes, 2)

	// Nodes shouldn't have snapshot files yet
	for _, node := range nodes {
		dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap-v3-encrypted"))
		assert.NoError(t, err)
		assert.Len(t, dirents, 0)
	}

	// Trigger a snapshot, with a 4th proposal
	_, err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeIDs[3])
	assert.NoError(t, err, "failed to propose value")

	// Nodes should now have a snapshot file
	for nodeIdx, node := range nodes {
		assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
			dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap-v3-encrypted"))
			if err != nil {
				return err
			}
			if len(dirents) != 1 {
				return fmt.Errorf("expected 1 snapshot, found %d on node %d", len(dirents), nodeIdx+1)
			}
			return nil
		}))
	}

	// Join another node
	nodes[4] = raftutils.NewJoinNode(t, clockSource, nodes[1].Address, tc)
	raftutils.WaitForCluster(t, clockSource, nodes)

	// Only restart the first node with force-new-cluster option
	nodes[1].Server.Stop()
	nodes[1].ShutdownRaft()
	nodes[1] = raftutils.RestartNode(t, clockSource, nodes[1], true)
	delete(nodes, 3)
	delete(nodes, 4)
	raftutils.WaitForCluster(t, clockSource, nodes)

	// The memberlist should contain exactly one node (self)
	memberlist := nodes[1].GetMemberlist()
	require.Len(t, memberlist, 1)

	// Propose a 5th value
	_, err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeIDs[4])
	require.NoError(t, err)
}