Clean up raft servers without a corresponding serf entry

consul/autopilot.go

@@ -78,17 +78,37 @@ func (s *Server) pruneDeadServers() error {
 
 	// Find any failed servers
 	var failed []string
+	staleRaftServers := make(map[string]raft.Server)
 	if autopilotConf.CleanupDeadServers {
+		future := s.raft.GetConfiguration()
+		if future.Error() != nil {
+			return err
+		}
+
+		for _, server := range future.Configuration().Servers {
+			staleRaftServers[string(server.Address)] = server
+		}
+
 		for _, member := range s.serfLAN.Members() {
-			valid, _ := agent.IsConsulServer(member)
-			if valid && member.Status == serf.StatusFailed {
-				failed = append(failed, member.Name)
+			valid, parts := agent.IsConsulServer(member)
+
+			if valid {
+				// Remove this server from the stale list; it has a serf entry
+				if _, ok := staleRaftServers[parts.Addr.String()]; ok {
+					delete(staleRaftServers, parts.Addr.String())
+				}
+
+				if member.Status == serf.StatusFailed {
+					failed = append(failed, member.Name)
+				}
 			}
 		}
 	}
 
+	removalCount := len(failed) + len(staleRaftServers)
+
 	// Nothing to remove, return early
-	if len(failed) == 0 {
+	if removalCount == 0 {
 		return nil
 	}
 
@@ -98,13 +118,17 @@ func (s *Server) pruneDeadServers() error {
 	}
 
 	// Only do removals if a minority of servers will be affected
-	if len(failed) < peers/2 {
+	if removalCount < peers/2 {
 		for _, server := range failed {
 			s.logger.Printf("[INFO] consul: Attempting removal of failed server: %v", server)
 			go s.serfLAN.RemoveFailedNode(server)
 		}
+		for _, raftServer := range staleRaftServers {
+			s.logger.Printf("[INFO] consul: Attempting removal of stale raft server : %v", raftServer.ID)
+			s.raft.RemoveServer(raftServer.ID, 0, 0)
+		}
 	} else {
-		s.logger.Printf("[DEBUG] consul: Failed to remove dead servers: too many dead servers: %d/%d", len(failed), peers)
+		s.logger.Printf("[DEBUG] consul: Failed to remove dead servers: too many dead servers: %d/%d", removalCount, peers)
 	}
 
 	return nil

consul/autopilot_test.go

@@ -153,6 +153,69 @@ func TestAutopilot_CleanupDeadServerPeriodic(t *testing.T) {
 	}
 }
 
+func TestAutopilot_CleanupStaleRaftServer(t *testing.T) {
+	dir1, s1 := testServerDCBootstrap(t, "dc1", true)
+	defer os.RemoveAll(dir1)
+	defer s1.Shutdown()
+
+	dir2, s2 := testServerDCBootstrap(t, "dc1", false)
+	defer os.RemoveAll(dir2)
+	defer s2.Shutdown()
+
+	dir3, s3 := testServerDCBootstrap(t, "dc1", false)
+	defer os.RemoveAll(dir3)
+	defer s3.Shutdown()
+
+	dir4, s4 := testServerDCBootstrap(t, "dc1", false)
+	defer os.RemoveAll(dir4)
+	defer s4.Shutdown()
+
+	servers := []*Server{s1, s2, s3}
+
+	// Join the servers to s1
+	addr := fmt.Sprintf("127.0.0.1:%d",
+		s1.config.SerfLANConfig.MemberlistConfig.BindPort)
+
+	for _, s := range servers[1:] {
+		if _, err := s.JoinLAN([]string{addr}); err != nil {
+			t.Fatalf("err: %v", err)
+		}
+	}
+
+	for _, s := range servers {
+		if err := testutil.WaitForResult(func() (bool, error) {
+			peers, _ := s.numPeers()
+			return peers == 3, nil
+		}); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// Add s4 to peers directly
+	s4addr := fmt.Sprintf("127.0.0.1:%d",
+		s4.config.SerfLANConfig.MemberlistConfig.BindPort)
+	s1.raft.AddVoter(raft.ServerID(s4.config.NodeID), raft.ServerAddress(s4addr),0, 0)
+
+	// Verify we have 4 peers
+	peers, err := s1.numPeers()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if peers != 4 {
+		t.Fatalf("bad: %v", peers)
+	}
+
+	// Wait for s4 to be removed
+	for _, s := range []*Server{s1, s2, s3} {
+		if err := testutil.WaitForResult(func() (bool, error) {
+			peers, _ := s.numPeers()
+			return peers == 3, nil
+		}); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
 func TestAutopilot_PromoteNonVoter(t *testing.T) {
 	dir1, s1 := testServerWithConfig(t, func(c *Config) {
 		c.Datacenter = "dc1"