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")}
n, ctx = raftutils.CopyNode(t, clockSource, nodes[1], false, raftutils.NewSimpleKeyRotator(singleKey))
require.Error(t, n.Node.JoinAndStart(ctx),
"should not have been able to restart since we can't read all the WALs, even if we can read the snapshot")
singleKey = raft.EncryptionKeys{CurrentDEK: []byte("key3")}
n, ctx = raftutils.CopyNode(t, clockSource, nodes[1], false, raftutils.NewSimpleKeyRotator(singleKey))
require.Error(t, n.Node.JoinAndStart(ctx),
"should not have been able to restart since we can't read all the WALs, and also not the snapshot")
nodes[1], ctx = raftutils.CopyNode(t, clockSource, nodes[1], false,
raftutils.NewSimpleKeyRotator(raft.EncryptionKeys{
CurrentDEK: []byte("key2"),
PendingDEK: []byte("key3"),
}))
require.NoError(t, nodes[1].Node.JoinAndStart(ctx))
// we can load, but we still need a snapshot because rotation hasn't finished
snapshots, err := storage.ListSnapshots(snapDir)
require.NoError(t, err)
require.Len(t, snapshots, 1, "expected 1 snapshot")
require.True(t, nodes[1].KeyRotator.NeedsRotation())
currSnapshot := snapshots[0]
// start the node - everything should fix itself
go nodes[1].Node.Run(ctx)
raftutils.WaitForCluster(t, clockSource, nodes)
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 snapshots, found %d on new node", len(snapshots))
}
if snapshots[0] == currSnapshot {
return fmt.Errorf("new snapshot not done yet")
}
if nodes[1].KeyRotator.NeedsRotation() {
return fmt.Errorf("rotation never finished")
}
currSnapshot = snapshots[0]
return nil
}))
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)
// If we can't update the keys, we wait for the next snapshot to do so
nodes[1].KeyRotator.SetUpdateFunc(func() error { return fmt.Errorf("nope!") })
nodes[1].KeyRotator.QueuePendingKey([]byte("key4"))
nodes[1].KeyRotator.RotationNotify() <- struct{}{}
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 snapshots, found %d on new node", len(snapshots))
}
if snapshots[0] == currSnapshot {
return fmt.Errorf("new snapshot not done yet")
}
currSnapshot = snapshots[0]
return nil
}))
require.True(t, nodes[1].KeyRotator.NeedsRotation())
// Fix updating the key rotator, and propose a 6th value - this should trigger the key
// rotation to finish
nodes[1].KeyRotator.SetUpdateFunc(nil)
nodeIDs = append(nodeIDs, "id6")
v, err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, "id6")
require.NoError(t, err, "failed to propose value")
values = append(values, v)
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)
require.NoError(t, raftutils.PollFunc(clockSource, func() error {
if nodes[1].KeyRotator.NeedsRotation() {
return fmt.Errorf("rotation never finished")
}
return nil
}))
// no new snapshot
snapshots, err = storage.ListSnapshots(snapDir)
require.NoError(t, err)
require.Len(t, snapshots, 1)
require.Equal(t, currSnapshot, snapshots[0])
// Even if something goes wrong with getting keys, and needs rotation returns a false positive,
// if there's no PendingDEK nothing happens.
fakeTrue := true
nodes[1].KeyRotator.SetNeedsRotation(&fakeTrue)
nodes[1].KeyRotator.RotationNotify() <- struct{}{}
// propose another value
nodeIDs = append(nodeIDs, "id7")
v, err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, "id7")
require.NoError(t, err, "failed to propose value")
values = append(values, v)
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)
// no new snapshot
snapshots, err = storage.ListSnapshots(snapDir)
require.NoError(t, err)
require.Len(t, snapshots, 1)
require.Equal(t, currSnapshot, snapshots[0])
// and when we restart, we can restart with the original key (the WAL written for the new proposed value)
// is written with the old key
nodes[1].Server.Stop()
nodes[1].ShutdownRaft()
nodes[1].KeyRotator = raftutils.NewSimpleKeyRotator(raft.EncryptionKeys{
CurrentDEK: []byte("key4"),
})
nodes[1] = raftutils.RestartNode(t, clockSource, nodes[1], false)
raftutils.WaitForCluster(t, clockSource, nodes)
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)
}
func TestRaftSnapshotRestart(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", "id6", "id7"}
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)
assert.NoError(t, err, "failed to propose value")
}
// Take down node 3
nodes[3].Server.Stop()
nodes[3].Shutdown()
// Propose a 4th value before the snapshot
values[3], err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeIDs[3])
assert.NoError(t, err, "failed to propose value")
// Remaining nodes shouldn't have snapshot files yet
for _, node := range []*raftutils.TestNode{nodes[1], nodes[2]} {
dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap"))
assert.NoError(t, err)
assert.Len(t, dirents, 0)
}
// Add a node to the cluster before the snapshot. This is the event
// that triggers the snapshot.
nodes[4] = raftutils.NewJoinNode(t, clockSource, nodes[1].Address, tc)
raftutils.WaitForCluster(t, clockSource, map[uint64]*raftutils.TestNode{1: nodes[1], 2: nodes[2], 4: nodes[4]})
// Remaining nodes should now have a snapshot file
for nodeIdx, node := range []*raftutils.TestNode{nodes[1], nodes[2]} {
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap"))
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
}))
}
raftutils.CheckValuesOnNodes(t, clockSource, map[uint64]*raftutils.TestNode{1: nodes[1], 2: nodes[2]}, nodeIDs[:4], values[:4])
// Propose a 5th value
values[4], err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeIDs[4])
require.NoError(t, err)
// Add another node to the cluster
nodes[5] = raftutils.NewJoinNode(t, clockSource, nodes[1].Address, tc)
raftutils.WaitForCluster(t, clockSource, map[uint64]*raftutils.TestNode{1: nodes[1], 2: nodes[2], 4: nodes[4], 5: nodes[5]})
// New node should get a copy of the snapshot
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(nodes[5].StateDir, "snap"))
if err != nil {
return err
}
if len(dirents) != 1 {
return fmt.Errorf("expected 1 snapshot, found %d on new node", len(dirents))
}
return nil
}))
dirents, err := ioutil.ReadDir(filepath.Join(nodes[5].StateDir, "snap"))
assert.NoError(t, err)
assert.Len(t, dirents, 1)
raftutils.CheckValuesOnNodes(t, clockSource, map[uint64]*raftutils.TestNode{1: nodes[1], 2: nodes[2]}, nodeIDs[:5], values[:5])
// It should know about the other nodes, including the one that was just added
stripMembers := func(memberList map[uint64]*api.RaftMember) map[uint64]*api.RaftMember {
raftNodes := make(map[uint64]*api.RaftMember)
for k, v := range memberList {
raftNodes[k] = &api.RaftMember{
RaftID: v.RaftID,
Addr: v.Addr,
}
}
return raftNodes
}
assert.Equal(t, stripMembers(nodes[1].GetMemberlist()), stripMembers(nodes[4].GetMemberlist()))
// Restart node 3
nodes[3] = raftutils.RestartNode(t, clockSource, nodes[3], false)
raftutils.WaitForCluster(t, clockSource, nodes)
// Node 3 should know about other nodes, including the new one
assert.Len(t, nodes[3].GetMemberlist(), 5)
assert.Equal(t, stripMembers(nodes[1].GetMemberlist()), stripMembers(nodes[3].GetMemberlist()))
// Propose yet another value, to make sure the rejoined node is still
// receiving new logs
values[5], err = raftutils.ProposeValue(t, raftutils.Leader(nodes), DefaultProposalTime, nodeIDs[5])
require.NoError(t, err)
// All nodes should have all the data
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs[:6], values[:6])
// Restart node 3 again. It should load the snapshot.
nodes[3].Server.Stop()
nodes[3].Shutdown()
nodes[3] = raftutils.RestartNode(t, clockSource, nodes[3], false)
raftutils.WaitForCluster(t, clockSource, nodes)
assert.Len(t, nodes[3].GetMemberlist(), 5)
assert.Equal(t, stripMembers(nodes[1].GetMemberlist()), stripMembers(nodes[3].GetMemberlist()))
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs[:6], values[:6])
// Propose again. Just to check consensus after this latest restart.
values[6], err = raftutils.ProposeValue(t, raftutils.Leader(nodes), DefaultProposalTime, nodeIDs[6])
require.NoError(t, err)
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)
}
func TestRaftSnapshot(t *testing.T) {
t.Parallel()
// Bring up a 3 node cluster
nodes, clockSource := raftutils.NewRaftCluster(t, tc, &api.RaftConfig{SnapshotInterval: 9, LogEntriesForSlowFollowers: 0})
defer raftutils.TeardownCluster(t, nodes)
nodeIDs := []string{"id1", "id2", "id3", "id4", "id5", "id6", "id7", "id8", "id9", "id10", "id11", "id12"}
values := make([]*api.Node, len(nodeIDs))
snapshotFilenames := make(map[uint64]string, 4)
// Propose 3 values
var err error
for i, nodeID := range nodeIDs[:3] {
values[i], err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeID)
assert.NoError(t, err, "failed to propose value")
}
// None of the nodes should have snapshot files yet
for _, node := range nodes {
dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap"))
assert.NoError(t, err)
assert.Len(t, dirents, 0)
}
// Check all nodes have all the data.
// This also acts as a synchronization point so that the next value we
// propose will arrive as a separate message to the raft state machine,
// and it is guaranteed to have the right cluster settings when
// deciding whether to create a new snapshot.
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs[:3], values)
// Propose a 4th value
values[3], err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeIDs[3])
assert.NoError(t, err, "failed to propose value")
// All nodes should now have a snapshot file
for nodeID, node := range nodes {
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap"))
if err != nil {
return err
}
if len(dirents) != 1 {
return fmt.Errorf("expected 1 snapshot, found %d", len(dirents))
}
snapshotFilenames[nodeID] = dirents[0].Name()
return nil
}))
}
// Add a node to the cluster
raftutils.AddRaftNode(t, clockSource, nodes, tc)
// It should get a copy of the snapshot
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(nodes[4].StateDir, "snap"))
if err != nil {
return err
}
if len(dirents) != 1 {
return fmt.Errorf("expected 1 snapshot, found %d on new node", len(dirents))
}
snapshotFilenames[4] = dirents[0].Name()
return nil
}))
// It should know about the other nodes
stripMembers := func(memberList map[uint64]*api.RaftMember) map[uint64]*api.RaftMember {
raftNodes := make(map[uint64]*api.RaftMember)
for k, v := range memberList {
raftNodes[k] = &api.RaftMember{
RaftID: v.RaftID,
Addr: v.Addr,
}
}
return raftNodes
}
assert.Equal(t, stripMembers(nodes[1].GetMemberlist()), stripMembers(nodes[4].GetMemberlist()))
// All nodes should have all the data
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs[:4], values)
// Propose more values to provoke a second snapshot
for i := 4; i != len(nodeIDs); i++ {
values[i], err = raftutils.ProposeValue(t, nodes[1], DefaultProposalTime, nodeIDs[i])
assert.NoError(t, err, "failed to propose value")
}
// All nodes should have a snapshot under a *different* name
for nodeID, node := range nodes {
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(node.StateDir, "snap"))
if err != nil {
return err
}
if len(dirents) != 1 {
return fmt.Errorf("expected 1 snapshot, found %d on node %d", len(dirents), nodeID)
}
if dirents[0].Name() == snapshotFilenames[nodeID] {
return fmt.Errorf("snapshot %s did not get replaced", snapshotFilenames[nodeID])
}
return nil
}))
}
// All nodes should have all the data
raftutils.CheckValuesOnNodes(t, clockSource, nodes, nodeIDs, values)
}
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 TestGCWAL(t *testing.T) {
t.Parallel()
// Additional log entries from cluster setup, leader election
extraLogEntries := 5
// Number of large entries to propose
proposals := 8
// Bring up a 3 node cluster
nodes, clockSource := raftutils.NewRaftCluster(t, tc, &api.RaftConfig{SnapshotInterval: uint64(proposals + extraLogEntries), LogEntriesForSlowFollowers: 0})
for i := 0; i != proposals; i++ {
_, err := proposeLargeValue(t, nodes[1], DefaultProposalTime, fmt.Sprintf("id%d", i))
assert.NoError(t, err, "failed to propose value")
}
time.Sleep(250 * time.Millisecond)
// Snapshot should have been triggered just as the WAL rotated, so
// both WAL files should be preserved
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(nodes[1].StateDir, "snap"))
if err != nil {
return err
}
if len(dirents) != 1 {
return fmt.Errorf("expected 1 snapshot, found %d", len(dirents))
}
dirents, err = ioutil.ReadDir(filepath.Join(nodes[1].StateDir, "wal"))
if err != nil {
return err
}
var walCount int
for _, f := range dirents {
if strings.HasSuffix(f.Name(), ".wal") {
walCount++
}
}
if walCount != 2 {
return fmt.Errorf("expected 2 WAL files, found %d", walCount)
}
return nil
}))
raftutils.TeardownCluster(t, nodes)
// Repeat this test, but trigger the snapshot after the WAL has rotated
proposals++
nodes, clockSource = raftutils.NewRaftCluster(t, tc, &api.RaftConfig{SnapshotInterval: uint64(proposals + extraLogEntries), LogEntriesForSlowFollowers: 0})
defer raftutils.TeardownCluster(t, nodes)
for i := 0; i != proposals; i++ {
_, err := proposeLargeValue(t, nodes[1], DefaultProposalTime, fmt.Sprintf("id%d", i))
assert.NoError(t, err, "failed to propose value")
}
time.Sleep(250 * time.Millisecond)
// This time only one WAL file should be saved.
assert.NoError(t, raftutils.PollFunc(clockSource, func() error {
dirents, err := ioutil.ReadDir(filepath.Join(nodes[1].StateDir, "snap"))
if err != nil {
return err
}
if len(dirents) != 1 {
return fmt.Errorf("expected 1 snapshot, found %d", len(dirents))
}
dirents, err = ioutil.ReadDir(filepath.Join(nodes[1].StateDir, "wal"))
if err != nil {
return err
}
var walCount int
for _, f := range dirents {
if strings.HasSuffix(f.Name(), ".wal") {
walCount++
}
}
if walCount != 1 {
return fmt.Errorf("expected 1 WAL file, found %d", walCount)
}
return nil
}))
// Restart the whole cluster
for _, node := range nodes {
node.Server.Stop()
node.Shutdown()
}
raftutils.AdvanceTicks(clockSource, 5)
i := 0
for k, node := range nodes {
nodes[k] = raftutils.RestartNode(t, clockSource, node, false)
i++
}
raftutils.WaitForCluster(t, clockSource, nodes)
// Is the data intact after restart?
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) != proposals {
err = fmt.Errorf("expected %d nodes, got %d", proposals, len(allNodes))
return
}
})
return err
}))
}
// It should still be possible to propose values
_, err := raftutils.ProposeValue(t, raftutils.Leader(nodes), DefaultProposalTime, "newnode")
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) != proposals+1 {
err = fmt.Errorf("expected %d nodes, got %d", proposals, len(allNodes))
return
}
})
return err
}))
}
}
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
break
}
}
assert.True(t, find)
// all nodes must have the same value
raftutils.CheckValuesOnNodes(t, clockSource, nodes, ids, values)
// ids should be a subset of pIDs
for _, id := range ids {
find = false
for _, pid := range pIDs {
if id == pid {
find = true
break
}
}
assert.True(t, find)
}
}
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)
}