integration: add network partition tests

integration/cluster.go

@@ -336,6 +336,7 @@ func (c *cluster) waitMembersMatch(t *testing.T, membs []client.Member) {
 
 func (c *cluster) WaitLeader(t *testing.T) int { return c.waitLeader(t, c.Members) }
 
+// waitLeader waits until given members agree on the same leader.
 func (c *cluster) waitLeader(t *testing.T, membs []*member) int {
 	possibleLead := make(map[uint64]bool)
 	var lead uint64
@@ -369,6 +370,28 @@ func (c *cluster) waitLeader(t *testing.T, membs []*member) int {
 	return -1
 }
 
+func (c *cluster) WaitNoLeader(t *testing.T) { c.waitNoLeader(t, c.Members) }
+
+// waitNoLeader waits until given members lose leader.
+func (c *cluster) waitNoLeader(t *testing.T, membs []*member) {
+	noLeader := false
+	for !noLeader {
+		noLeader = true
+		for _, m := range membs {
+			select {
+			case <-m.s.StopNotify():
+				continue
+			default:
+			}
+			if m.s.Lead() != 0 {
+				noLeader = false
+				time.Sleep(10 * tickDuration)
+				break
+			}
+		}
+	}
+}
+
 func (c *cluster) waitVersion() {
 	for _, m := range c.Members {
 		for {
@@ -502,6 +525,10 @@ func (m *member) listenGRPC() error {
 	return nil
 }
 
+func (m *member) electionTimeout() time.Duration {
+	return time.Duration(m.s.Cfg.ElectionTicks) * time.Millisecond
+}
+
 func (m *member) DropConnections() { m.grpcBridge.Reset() }
 
 // NewClientV3 creates a new grpc client connection to the member
@@ -741,6 +768,22 @@ func (m *member) Metric(metricName string) (string, error) {
 	return "", nil
 }
 
+// InjectPartition drops connections from m to others, vice versa.
+func (m *member) InjectPartition(t *testing.T, others []*member) {
+	for _, other := range others {
+		m.s.CutPeer(other.s.ID())
+		other.s.CutPeer(m.s.ID())
+	}
+}
+
+// RecoverPartition recovers connections from m to others, vice versa.
+func (m *member) RecoverPartition(t *testing.T, others []*member) {
+	for _, other := range others {
+		m.s.MendPeer(other.s.ID())
+		other.s.MendPeer(m.s.ID())
+	}
+}
+
 func MustNewHTTPClient(t *testing.T, eps []string, tls *transport.TLSInfo) client.Client {
 	cfgtls := transport.TLSInfo{}
 	if tls != nil {

integration/network_partition_test.go

@@ -0,0 +1,136 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package integration
+
+import (
+	"testing"
+	"time"
+
+	"github.com/coreos/etcd/pkg/testutil"
+)
+
+func TestNetworkPartition5MembersLeaderInMinority(t *testing.T) {
+	defer testutil.AfterTest(t)
+
+	clus := NewClusterV3(t, &ClusterConfig{Size: 5})
+	defer clus.Terminate(t)
+
+	leadIndex := clus.WaitLeader(t)
+
+	// minority: leader, follower / majority: follower, follower, follower
+	minority := []int{leadIndex, (leadIndex + 1) % 5}
+	majority := []int{(leadIndex + 2) % 5, (leadIndex + 3) % 5, (leadIndex + 4) % 5}
+
+	minorityMembers := getMembersByIndexSlice(clus.cluster, minority)
+	majorityMembers := getMembersByIndexSlice(clus.cluster, majority)
+
+	// network partition (bi-directional)
+	injectPartition(t, minorityMembers, majorityMembers)
+
+	// minority leader must be lost
+	clus.waitNoLeader(t, minorityMembers)
+
+	// wait extra election timeout
+	time.Sleep(2 * majorityMembers[0].electionTimeout())
+
+	// new leader must be from majority
+	clus.waitLeader(t, majorityMembers)
+
+	// recover network partition (bi-directional)
+	recoverPartition(t, minorityMembers, majorityMembers)
+	clusterMustProgress(t, clus.Members)
+}
+
+func TestNetworkPartition5MembersLeaderInMajority(t *testing.T) {
+	defer testutil.AfterTest(t)
+
+	clus := NewClusterV3(t, &ClusterConfig{Size: 5})
+	defer clus.Terminate(t)
+
+	leadIndex := clus.WaitLeader(t)
+
+	// majority: leader, follower, follower / minority: follower, follower
+	majority := []int{leadIndex, (leadIndex + 1) % 5, (leadIndex + 2) % 5}
+	minority := []int{(leadIndex + 3) % 5, (leadIndex + 4) % 5}
+
+	majorityMembers := getMembersByIndexSlice(clus.cluster, majority)
+	minorityMembers := getMembersByIndexSlice(clus.cluster, minority)
+
+	// network partition (bi-directional)
+	injectPartition(t, majorityMembers, minorityMembers)
+
+	// minority leader must be lost
+	clus.waitNoLeader(t, minorityMembers)
+
+	// wait extra election timeout
+	time.Sleep(2 * majorityMembers[0].electionTimeout())
+
+	// leader must be hold in majority
+	leadIndex2 := clus.waitLeader(t, majorityMembers)
+	leadID, leadID2 := clus.Members[leadIndex].s.ID(), majorityMembers[leadIndex2].s.ID()
+	if leadID != leadID2 {
+		t.Fatalf("unexpected leader change from %s, got %s", leadID, leadID2)
+	}
+
+	// recover network partition (bi-directional)
+	recoverPartition(t, majorityMembers, minorityMembers)
+	clusterMustProgress(t, clus.Members)
+}
+
+func TestNetworkPartition4Members(t *testing.T) {
+	defer testutil.AfterTest(t)
+
+	clus := NewClusterV3(t, &ClusterConfig{Size: 4})
+	defer clus.Terminate(t)
+
+	leadIndex := clus.WaitLeader(t)
+
+	// groupA: leader, follower / groupB: follower, follower
+	groupA := []int{leadIndex, (leadIndex + 1) % 4}
+	groupB := []int{(leadIndex + 2) % 4, (leadIndex + 3) % 4}
+
+	leaderPartition := getMembersByIndexSlice(clus.cluster, groupA)
+	followerPartition := getMembersByIndexSlice(clus.cluster, groupB)
+
+	// network partition (bi-directional)
+	injectPartition(t, leaderPartition, followerPartition)
+
+	// no group has quorum, so leader must be lost in all members
+	clus.WaitNoLeader(t)
+
+	// recover network partition (bi-directional)
+	recoverPartition(t, leaderPartition, followerPartition)
+	clusterMustProgress(t, clus.Members)
+}
+
+func getMembersByIndexSlice(clus *cluster, idxs []int) []*member {
+	ms := make([]*member, len(idxs))
+	for i, idx := range idxs {
+		ms[i] = clus.Members[idx]
+	}
+	return ms
+}
+
+func injectPartition(t *testing.T, src, others []*member) {
+	for _, m := range src {
+		m.InjectPartition(t, others)
+	}
+}
+
+func recoverPartition(t *testing.T, src, others []*member) {
+	for _, m := range src {
+		m.RecoverPartition(t, others)
+	}
+}