Bumps default Raft protocol to version 3. (#3477)

* Changes default Raft protocol to 3.

* Changes numPeers() to report only voters.

This should have been there before, but it's more obvious that this
is incorrect now that we default the Raft protocol to 3, which puts
new servers in a read-only state while Autopilot waits for them to
become healthy.

* Fixes TestLeader_RollRaftServer.

* Fixes TestOperator_RaftRemovePeerByAddress.

* Fixes TestServer_*.

Relaxed the check for a given number of voter peers and instead do
a thorough check that all servers see each other in their Raft
configurations.

* Fixes TestACL_*.

These now just check for Raft replication to be set up, and don't
care about the number of voter peers.

* Fixes TestOperator_Raft_ListPeers.

* Fixes TestAutopilot_CleanupDeadServerPeriodic.

* Fixes TestCatalog_ListNodes_ConsistentRead_Fail.

* Fixes TestLeader_ChangeServerID and adjusts the conn pool to throw away
sockets when it sees io.EOF.

* Changes version to 1.0.0 in the options doc.

* Makes metrics test more deterministic with autopilot metrics possible.

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 BREAKING CHANGES:
 
+* **Raft Protocol Defaults to 3:** The [`-raft-protocol`](https://www.consul.io/docs/agent/options.html#_raft_protocol) default has been changed from 2 to 3, enabling all Autopilot features by default. Version 3 requires Consul running 0.8.0 or newer on all servers in order to work, so if you are upgrading with older servers in a cluster then you will need to set this back to 2 in order to upgrade. See [Raft Protocol Version Compatibility](https://www.consul.io/docs/upgrade-specific.html#raft-protocol-version-compatibility) for more details. Also the format of `peers.json` used for outage recovery is different when running with the lastest Raft protocol. See [Manual Recovery Using peers.json](https://www.consul.io/docs/guides/outage.html#manual-recovery-using-peers-json) for a description of the required format.
+
 FEATURES:
 
 IMPROVEMENTS:
@@ -22,7 +24,7 @@ IMPROVEMENTS:
 * agent: Switched to using a read lock for the agent's RPC dispatcher, which prevents RPC calls from getting serialized. [GH-3376]
 * agent: When joining a cluster, Consul now skips the unique node ID constraint for Consul members running Consul older than 0.8.5. This makes it easier to upgrade to newer versions of Consul in an existing cluster with non-unique node IDs. [GH-3070]
 * build: Upgraded Go version to 1.9. [GH-3428]
-* server: Consul servers can re-establish quorum after all of them change their IP addresses upon a restart. [GH-1580] 
+* server: Consul servers can re-establish quorum after all of them change their IP addresses upon a restart. [GH-1580]
 
 BUG FIXES:
 

agent/consul/acl_test.go

@@ -235,7 +235,7 @@ func TestACL_NonAuthority_NotFound(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
+	retry.Run(t, func(r *retry.R) { r.Check(wantRaft([]*Server{s1, s2})) })
 
 	client := rpcClient(t, s1)
 	defer client.Close()
@@ -278,7 +278,7 @@ func TestACL_NonAuthority_Found(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
+	retry.Run(t, func(r *retry.R) { r.Check(wantRaft([]*Server{s1, s2})) })
 
 	testrpc.WaitForLeader(t, s1.RPC, "dc1")
 
@@ -346,7 +346,7 @@ func TestACL_NonAuthority_Management(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
+	retry.Run(t, func(r *retry.R) { r.Check(wantRaft([]*Server{s1, s2})) })
 
 	testrpc.WaitForLeader(t, s1.RPC, "dc1")
 
@@ -395,7 +395,7 @@ func TestACL_DownPolicy_Deny(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
+	retry.Run(t, func(r *retry.R) { r.Check(wantRaft([]*Server{s1, s2})) })
 
 	testrpc.WaitForLeader(t, s1.RPC, "dc1")
 
@@ -461,7 +461,7 @@ func TestACL_DownPolicy_Allow(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
+	retry.Run(t, func(r *retry.R) { r.Check(wantRaft([]*Server{s1, s2})) })
 
 	testrpc.WaitForLeader(t, s1.RPC, "dc1")
 
@@ -529,7 +529,7 @@ func TestACL_DownPolicy_ExtendCache(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
+	retry.Run(t, func(r *retry.R) { r.Check(wantRaft([]*Server{s1, s2})) })
 
 	testrpc.WaitForLeader(t, s1.RPC, "dc1")
 

agent/consul/autopilot_test.go

@@ -89,6 +89,7 @@ func TestAutopilot_CleanupDeadServerPeriodic(t *testing.T) {
 		c.Datacenter = "dc1"
 		c.Bootstrap = false
 	}
+
 	dir2, s2 := testServerWithConfig(t, conf)
 	defer os.RemoveAll(dir2)
 	defer s2.Shutdown()
@@ -101,24 +102,35 @@ func TestAutopilot_CleanupDeadServerPeriodic(t *testing.T) {
 	defer os.RemoveAll(dir4)
 	defer s4.Shutdown()
 
-	servers := []*Server{s1, s2, s3, s4}
+	dir5, s5 := testServerWithConfig(t, conf)
+	defer os.RemoveAll(dir5)
+	defer s5.Shutdown()
 
-	// Join the servers to s1
+	servers := []*Server{s1, s2, s3, s4, s5}
+
+	// Join the servers to s1, and wait until they are all promoted to
+	// voters.
 	for _, s := range servers[1:] {
 		joinLAN(t, s, s1)
 	}
-
-	for _, s := range servers {
-		retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s, 4)) })
-	}
+	retry.Run(t, func(r *retry.R) {
+		r.Check(wantRaft(servers))
+		for _, s := range servers {
+			r.Check(wantPeers(s, 5))
+		}
+	})
 
 	// Kill a non-leader server
 	s4.Shutdown()
 
 	// Should be removed from the peers automatically
-	for _, s := range []*Server{s1, s2, s3} {
-		retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s, 3)) })
-	}
+	servers = []*Server{s1, s2, s3, s5}
+	retry.Run(t, func(r *retry.R) {
+		r.Check(wantRaft(servers))
+		for _, s := range servers {
+			r.Check(wantPeers(s, 4))
+		}
+	})
 }
 
 func TestAutopilot_CleanupStaleRaftServer(t *testing.T) {

agent/consul/catalog_endpoint_test.go

@@ -779,29 +779,38 @@ func TestCatalog_ListNodes_ConsistentRead_Fail(t *testing.T) {
 	dir1, s1 := testServer(t)
 	defer os.RemoveAll(dir1)
 	defer s1.Shutdown()
-	codec1 := rpcClient(t, s1)
-	defer codec1.Close()
 
 	dir2, s2 := testServerDCBootstrap(t, "dc1", false)
 	defer os.RemoveAll(dir2)
 	defer s2.Shutdown()
-	codec2 := rpcClient(t, s2)
-	defer codec2.Close()
 
-	// Try to join
+	dir3, s3 := testServerDCBootstrap(t, "dc1", false)
+	defer os.RemoveAll(dir3)
+	defer s3.Shutdown()
+
+	// Try to join and wait for all servers to get promoted to voters.
 	joinLAN(t, s2, s1)
+	joinLAN(t, s3, s2)
+	servers := []*Server{s1, s2, s3}
+	retry.Run(t, func(r *retry.R) {
+		r.Check(wantRaft(servers))
+		for _, s := range servers {
+			r.Check(wantPeers(s, 3))
+		}
+	})
 
-	testrpc.WaitForLeader(t, s1.RPC, "dc1")
-	testrpc.WaitForLeader(t, s2.RPC, "dc1")
-
-	// Use the leader as the client, kill the follower
+	// Use the leader as the client, kill the followers.
 	var codec rpc.ClientCodec
-	if s1.IsLeader() {
-		codec = codec1
-		s2.Shutdown()
-	} else {
-		codec = codec2
-		s1.Shutdown()
+	for _, s := range servers {
+		if s.IsLeader() {
+			codec = rpcClient(t, s)
+			defer codec.Close()
+		} else {
+			s.Shutdown()
+		}
+	}
+	if codec == nil {
+		t.Fatalf("no leader")
 	}
 
 	args := structs.DCSpecificRequest{
@@ -813,7 +822,6 @@ func TestCatalog_ListNodes_ConsistentRead_Fail(t *testing.T) {
 	if err == nil || !strings.HasPrefix(err.Error(), "leadership lost") {
 		t.Fatalf("err: %v", err)
 	}
-
 	if out.QueryMeta.LastContact != 0 {
 		t.Fatalf("should not have a last contact time")
 	}

agent/consul/config.go

@@ -434,10 +434,9 @@ func DefaultConfig() *Config {
 	conf.SerfLANConfig.MemberlistConfig.BindPort = DefaultLANSerfPort
 	conf.SerfWANConfig.MemberlistConfig.BindPort = DefaultWANSerfPort
 
-	// TODO: default to 3 in Consul 0.9
-	// Use a transitional version of the raft protocol to interoperate with
-	// versions 1 and 3
-	conf.RaftConfig.ProtocolVersion = 2
+	// Raft protocol version 3 only works with other Consul servers running
+	// 0.8.0 or later.
+	conf.RaftConfig.ProtocolVersion = 3
 
 	// Disable shutdown on removal
 	conf.RaftConfig.ShutdownOnRemove = false

agent/consul/helper_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/hashicorp/consul/testutil/retry"
+	"github.com/hashicorp/raft"
 	"github.com/hashicorp/serf/serf"
 )
 
@@ -41,6 +42,42 @@ func wantPeers(s *Server, peers int) error {
 	return nil
 }
 
+// wantRaft determines if the servers have all of each other in their
+// Raft configurations,
+func wantRaft(servers []*Server) error {
+	// Make sure all the servers are represented in the Raft config,
+	// and that there are no extras.
+	verifyRaft := func(c raft.Configuration) error {
+		want := make(map[raft.ServerID]bool)
+		for _, s := range servers {
+			want[s.config.RaftConfig.LocalID] = true
+		}
+
+		for _, s := range c.Servers {
+			if !want[s.ID] {
+				return fmt.Errorf("don't want %q", s.ID)
+			}
+			delete(want, s.ID)
+		}
+
+		if len(want) > 0 {
+			return fmt.Errorf("didn't find %v", want)
+		}
+		return nil
+	}
+
+	for _, s := range servers {
+		future := s.raft.GetConfiguration()
+		if err := future.Error(); err != nil {
+			return err
+		}
+		if err := verifyRaft(future.Configuration()); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // joinAddrLAN returns the address other servers can
 // use to join the cluster on the LAN interface.
 func joinAddrLAN(s *Server) string {

agent/consul/leader_test.go

@@ -703,6 +703,7 @@ func TestLeader_RollRaftServer(t *testing.T) {
 	dir1, s1 := testServerWithConfig(t, func(c *Config) {
 		c.Bootstrap = true
 		c.Datacenter = "dc1"
+		c.RaftConfig.ProtocolVersion = 2
 	})
 	defer os.RemoveAll(dir1)
 	defer s1.Shutdown()
@@ -715,7 +716,11 @@ func TestLeader_RollRaftServer(t *testing.T) {
 	defer os.RemoveAll(dir2)
 	defer s2.Shutdown()
 
-	dir3, s3 := testServerDCBootstrap(t, "dc1", false)
+	dir3, s3 := testServerWithConfig(t, func(c *Config) {
+		c.Bootstrap = false
+		c.Datacenter = "dc1"
+		c.RaftConfig.ProtocolVersion = 2
+	})
 	defer os.RemoveAll(dir3)
 	defer s3.Shutdown()
 
@@ -803,10 +808,9 @@ func TestLeader_ChangeServerID(t *testing.T) {
 
 	servers := []*Server{s1, s2, s3}
 
-	// Try to join
+	// Try to join and wait for all servers to get promoted
 	joinLAN(t, s2, s1)
 	joinLAN(t, s3, s1)
-
 	for _, s := range servers {
 		retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s, 3)) })
 	}
@@ -841,10 +845,21 @@ func TestLeader_ChangeServerID(t *testing.T) {
 	joinLAN(t, s4, s1)
 	servers[2] = s4
 
+	// While integrating #3327 it uncovered that this test was flaky. The
+	// connection pool would use the same TCP connection to the old server
+	// which would give EOF errors to the autopilot health check RPC call.
+	// To make this more reliable we changed the connection pool to throw
+	// away the connection if it sees an EOF error, since there's no way
+	// that connection is going to work again. This made this test reliable
+	// since it will make a new connection to s4.
+
 	// Make sure the dead server is removed and we're back to 3 total peers
-	for _, s := range servers {
-		retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s, 3)) })
-	}
+	retry.Run(t, func(r *retry.R) {
+		r.Check(wantRaft(servers))
+		for _, s := range servers {
+			r.Check(wantPeers(s, 3))
+		}
+	})
 }
 
 func TestLeader_ACL_Initialization(t *testing.T) {

agent/consul/operator_raft_endpoint_test.go

@@ -6,6 +6,7 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/hashicorp/consul/acl"
 	"github.com/hashicorp/consul/agent/structs"
@@ -157,7 +158,8 @@ func TestOperator_RaftRemovePeerByAddress(t *testing.T) {
 
 	// Add it manually to Raft.
 	{
-		future := s1.raft.AddPeer(arg.Address)
+		id := raft.ServerID("fake-node-id")
+		future := s1.raft.AddVoter(id, arg.Address, 0, time.Second)
 		if err := future.Error(); err != nil {
 			t.Fatalf("err: %v", err)
 		}

agent/consul/server.go

@@ -588,8 +588,6 @@ func (s *Server) setupRaft() error {
 			return err
 		}
 		if !hasState {
-			// TODO (slackpad) - This will need to be updated when
-			// we add support for node IDs.
 			configuration := raft.Configuration{
 				Servers: []raft.Server{
 					raft.Server{
@@ -835,15 +833,22 @@ func (s *Server) Leave() error {
 	return nil
 }
 
-// numPeers is used to check on the number of known peers, including the local
-// node.
+// numPeers is used to check on the number of known peers, including potentially
+// the local node. We count only voters, since others can't actually become
+// leader, so aren't considered peers.
 func (s *Server) numPeers() (int, error) {
 	future := s.raft.GetConfiguration()
 	if err := future.Error(); err != nil {
 		return 0, err
 	}
-	configuration := future.Configuration()
-	return len(configuration.Servers), nil
+
+	var numPeers int
+	for _, server := range future.Configuration().Servers {
+		if server.Suffrage == raft.Voter {
+			numPeers++
+		}
+	}
+	return numPeers, nil
 }
 
 // JoinLAN is used to have Consul join the inner-DC pool

agent/consul/server_test.go

@@ -492,18 +492,10 @@ func TestServer_JoinLAN_TLS(t *testing.T) {
 
 	// Try to join
 	joinLAN(t, s2, s1)
-	retry.Run(t, func(r *retry.R) {
-		if got, want := len(s1.LANMembers()), 2; got != want {
-			r.Fatalf("got %d s1 LAN members want %d", got, want)
-		}
-		if got, want := len(s2.LANMembers()), 2; got != want {
-			r.Fatalf("got %d s2 LAN members want %d", got, want)
-		}
-	})
+
 	// Verify Raft has established a peer
 	retry.Run(t, func(r *retry.R) {
-		r.Check(wantPeers(s1, 2))
-		r.Check(wantPeers(s2, 2))
+		r.Check(wantRaft([]*Server{s1, s2}))
 	})
 }
 
@@ -555,10 +547,7 @@ func TestServer_Expect(t *testing.T) {
 
 	// Wait for the new server to see itself added to the cluster.
 	retry.Run(t, func(r *retry.R) {
-		r.Check(wantPeers(s1, 4))
-		r.Check(wantPeers(s2, 4))
-		r.Check(wantPeers(s3, 4))
-		r.Check(wantPeers(s4, 4))
+		r.Check(wantRaft([]*Server{s1, s2, s3, s4}))
 	})
 
 	// Make sure there's still a leader and that the term didn't change,
@@ -661,16 +650,10 @@ func TestServer_Encrypted(t *testing.T) {
 }
 
 func testVerifyRPC(s1, s2 *Server, t *testing.T) (bool, error) {
-	// Try to join
-	addr := fmt.Sprintf("127.0.0.1:%d",
-		s1.config.SerfLANConfig.MemberlistConfig.BindPort)
-	if _, err := s2.JoinLAN([]string{addr}); err != nil {
-		t.Fatalf("err: %v", err)
-	}
-
-	// make sure both servers know about each other
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s1, 2)) })
-	retry.Run(t, func(r *retry.R) { r.Check(wantPeers(s2, 2)) })
+	joinLAN(t, s1, s2)
+	retry.Run(t, func(r *retry.R) {
+		r.Check(wantRaft([]*Server{s1, s2}))
+	})
 
 	// Have s2 make an RPC call to s1
 	var leader *metadata.Server

agent/pool/pool.go

@@ -413,6 +413,15 @@ func (p *ConnPool) RPC(dc string, addr net.Addr, version int, method string, use
 	err = msgpackrpc.CallWithCodec(sc.codec, method, args, reply)
 	if err != nil {
 		sc.Close()
+
+		// See the comment in leader_test.go TestLeader_ChangeServerID
+		// about how we found this. The tldr is that if we see this
+		// error, we know this connection is toast, so we should clear
+		// it and make a new one on the next attempt.
+		if err == io.EOF {
+			p.clearConn(conn)
+		}
+
 		p.releaseConn(conn)
 		return fmt.Errorf("rpc error: %v", err)
 	}

api/agent_test.go

@@ -41,12 +41,15 @@ func TestAPI_AgentMetrics(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	}
 
-	if len(metrics.Gauges) < 0 {
-		t.Fatalf("bad: %v", metrics)
+	var found bool
+	for _, g := range metrics.Gauges {
+		if g.Name == "consul.runtime.alloc_bytes" {
+			found = true
+			break
+		}
 	}
-
-	if metrics.Gauges[0].Name != "consul.runtime.alloc_bytes" {
-		t.Fatalf("bad: %v", metrics.Gauges[0])
+	if !found {
+		t.Fatalf("missing runtime metrics")
 	}
 }
 

command/operator_raft_list_test.go

@@ -19,8 +19,8 @@ func TestOperator_Raft_ListPeers(t *testing.T) {
 	a := agent.NewTestAgent(t.Name(), ``)
 	defer a.Shutdown()
 
-	expected := fmt.Sprintf("%s  127.0.0.1:%d  127.0.0.1:%d  leader  true   2",
-		a.Config.NodeName, a.Config.ServerPort, a.Config.ServerPort)
+	expected := fmt.Sprintf("%s  %s  127.0.0.1:%d  leader  true   3",
+		a.Config.NodeName, a.Config.NodeID, a.Config.ServerPort)
 
 	// Test the legacy mode with 'consul operator raft -list-peers'
 	{

website/source/docs/agent/options.html.md

@@ -458,9 +458,11 @@ will exit with an error at startup.
   You can view the protocol versions supported by Consul by running `consul -v`.
 
 * <a name="_raft_protocol"></a><a href="#_raft_protocol">`-raft-protocol`</a> - This controls the internal
-  version of the Raft consensus protocol used for server communications. This defaults to 2 but must
-  be set to 3 in order to gain access to Autopilot features, with the exception of
-  [`cleanup_dead_servers`](#cleanup_dead_servers).
+  version of the Raft consensus protocol used for server communications. This must be set to 3 in order to
+  gain access to Autopilot features, with the exception of [`cleanup_dead_servers`](#cleanup_dead_servers).
+  Defaults to 3 in Consul 1.0.0 and later (defaulted to 2 previously). See
+  [Raft Protocol Version Compatibility](/docs/upgrade-specific.html#raft-protocol-version-compatibility)
+  for more details.
 
 * <a name="_recursor"></a><a href="#_recursor">`-recursor`</a> - Specifies the address of an upstream DNS
   server. This option may be provided multiple times, and is functionally