Read-replica instead of non-voter (#10875)

api/sys_raft.go

@@ -24,7 +24,7 @@ type RaftJoinRequest struct {
 	LeaderClientCert string `json:"leader_client_cert"`
 	LeaderClientKey  string `json:"leader_client_key"`
 	Retry            bool   `json:"retry"`
-	NonVoter         bool   `json:"non_voter"`
+	ReadReplica      bool   `json:"read_replica"`
 }
 
 // RaftJoin adds the node from which this call is invoked from to the raft

command/operator_raft_join.go

@@ -14,13 +14,16 @@ var _ cli.CommandAutocomplete = (*OperatorRaftJoinCommand)(nil)
 
 type OperatorRaftJoinCommand struct {
 	flagRetry            bool
-	flagNonVoter         bool
 	flagLeaderCACert     string
 	flagLeaderClientCert string
 	flagLeaderClientKey  string
 	flagAutoJoinScheme   string
 	flagAutoJoinPort     uint
+	flagReadReplica      bool
 	*BaseCommand
+
+	// Deprecated flags
+	flagNonVoter bool
 }
 
 func (c *OperatorRaftJoinCommand) Synopsis() string {
@@ -113,6 +116,13 @@ func (c *OperatorRaftJoinCommand) Flags() *FlagSets {
 		Name:    "non-voter",
 		Target:  &c.flagNonVoter,
 		Default: false,
+		Usage:   "DEPRECATED: Use -read-replica instead.",
+	})
+
+	f.BoolVar(&BoolVar{
+		Name:    "read-replica",
+		Target:  &c.flagReadReplica,
+		Default: false,
 		Usage:   "(Enterprise-only) This flag is used to make the server not participate in the Raft quorum, and have it only receive the data replication stream. This can be used to add read scalability to a cluster in cases where a high volume of reads to servers are needed.",
 	})
 
@@ -148,6 +158,15 @@ func (c *OperatorRaftJoinCommand) Run(args []string) int {
 		return 1
 	}
 
+	switch {
+	case c.flagReadReplica:
+		// Prioritize -read-replica flag.
+		c.flagNonVoter = true
+	case c.flagNonVoter:
+		// If the deprecated -non-voter is used, update the -read-replica flag value.
+		c.flagReadReplica = true
+	}
+
 	leaderCACert, err := parseFlagFile(c.flagLeaderCACert)
 	if err != nil {
 		c.UI.Error(fmt.Sprintf("Failed to parse leader CA certificate: %s", err))
@@ -182,7 +201,7 @@ func (c *OperatorRaftJoinCommand) Run(args []string) int {
 		LeaderClientCert: leaderClientCert,
 		LeaderClientKey:  leaderClientKey,
 		Retry:            c.flagRetry,
-		NonVoter:         c.flagNonVoter,
+		ReadReplica:      c.flagReadReplica,
 	}
 
 	if strings.Contains(leaderInfo, "provider=") {

http/sys_raft.go

@@ -51,8 +51,8 @@ func handleSysRaftJoinPost(core *vault.Core, w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	if req.NonVoter && !nonVotersAllowed {
-		respondError(w, http.StatusBadRequest, errors.New("non-voting nodes not allowed"))
+	if req.ReadReplica && !readReplicasAllowed {
+		respondError(w, http.StatusBadRequest, errors.New("read-replica nodes not allowed"))
 		return
 	}
 
@@ -83,7 +83,7 @@ func handleSysRaftJoinPost(core *vault.Core, w http.ResponseWriter, r *http.Requ
 		},
 	}
 
-	joined, err := core.JoinRaftCluster(context.Background(), leaderInfos, req.NonVoter)
+	joined, err := core.JoinRaftCluster(context.Background(), leaderInfos, req.ReadReplica)
 	if err != nil {
 		respondError(w, http.StatusInternalServerError, err)
 		return
@@ -109,5 +109,5 @@ type JoinRequest struct {
 	LeaderClientKey     string `json:"leader_client_key"`
 	LeaderTLSServerName string `json:"leader_tls_servername"`
 	Retry               bool   `json:"retry"`
-	NonVoter            bool   `json:"non_voter"`
+	ReadReplica         bool   `json:"read_replica"`
 }

http/util.go

@@ -27,7 +27,7 @@ var (
 
 	additionalRoutes = func(mux *http.ServeMux, core *vault.Core) {}
 
-	nonVotersAllowed = false
+	readReplicasAllowed = false
 )
 
 func rateLimitQuotaWrapping(handler http.Handler, core *vault.Core) http.Handler {

physical/raft/raft.go

@@ -713,7 +713,7 @@ func (b *RaftBackend) SetupCluster(ctx context.Context, opts SetupOpts) error {
 		// Non-voting servers are only allowed in enterprise. If Suffrage is disabled,
 		// error out to indicate that it isn't allowed.
 		for idx := range recoveryConfig.Servers {
-			if !nonVotersAllowed && recoveryConfig.Servers[idx].Suffrage == raft.Nonvoter {
+			if !readReplicasAllowed && recoveryConfig.Servers[idx].Suffrage == raft.Nonvoter {
 				return fmt.Errorf("raft recovery failed to parse configuration for node %q: setting `non_voter` is only supported in enterprise", recoveryConfig.Servers[idx].ID)
 			}
 		}

physical/raft/raft_util.go

@@ -7,9 +7,10 @@ import (
 	"errors"
 )
 
-const nonVotersAllowed = false
+const readReplicasAllowed = false
 
-// AddPeer adds a new server to the raft cluster
-func (b *RaftBackend) AddNonVotingPeer(ctx context.Context, peerID, clusterAddr string) error {
+// AddReadReplicaPeer adds a new server to the raft cluster which does not have
+// voting rights but gets all the data replicated to it.
+func (b *RaftBackend) AddReadReplicaPeer(ctx context.Context, peerID, clusterAddr string) error {
 	return errors.New("not implemented")
 }

vault/core.go

@@ -163,7 +163,7 @@ type raftInformation struct {
 	challenge           *wrapping.EncryptedBlobInfo
 	leaderClient        *api.Client
 	leaderBarrierConfig *SealConfig
-	nonVoter            bool
+	readReplica         bool
 	joinInProgress      bool
 }
 

vault/logical_system_raft.go

@@ -34,6 +34,10 @@ func (b *SystemBackend) raftStoragePaths() []*framework.Path {
 					Type: framework.TypeString,
 				},
 				"non_voter": {
+					Type:       framework.TypeBool,
+					Deprecated: true,
+				},
+				"read_replica": {
 					Type: framework.TypeBool,
 				},
 			},
@@ -256,7 +260,13 @@ func (b *SystemBackend) handleRaftBootstrapAnswerWrite() framework.OperationFunc
 			return logical.ErrorResponse("no cluster_addr provided"), logical.ErrInvalidRequest
 		}
 
-		nonVoter := d.Get("non_voter").(bool)
+		// Prioritize read_replica parameter
+		readReplica := d.Get("read_replica").(bool)
+
+		// If the deprecated non_voter is used, consider that as well
+		if !readReplica && d.Get("non_voter").(bool) {
+			readReplica = true
+		}
 
 		answer, err := base64.StdEncoding.DecodeString(answerRaw)
 		if err != nil {
@@ -286,9 +296,9 @@ func (b *SystemBackend) handleRaftBootstrapAnswerWrite() framework.OperationFunc
 			return nil, errors.New("could not decode raft TLS configuration")
 		}
 
-		switch nonVoter {
+		switch readReplica {
 		case true:
-			err = raftBackend.AddNonVotingPeer(ctx, serverID, clusterAddr)
+			err = raftBackend.AddReadReplicaPeer(ctx, serverID, clusterAddr)
 		default:
 			err = raftBackend.AddPeer(ctx, serverID, clusterAddr)
 		}

vault/raft.go

@@ -710,7 +710,7 @@ func (c *Core) InitiateRetryJoin(ctx context.Context) error {
 	return nil
 }
 
-func (c *Core) JoinRaftCluster(ctx context.Context, leaderInfos []*raft.LeaderJoinInfo, nonVoter bool) (bool, error) {
+func (c *Core) JoinRaftCluster(ctx context.Context, leaderInfos []*raft.LeaderJoinInfo, readReplica bool) (bool, error) {
 	raftBackend := c.getRaftBackend()
 	if raftBackend == nil {
 		return false, errors.New("raft backend not in use")
@@ -881,7 +881,7 @@ func (c *Core) JoinRaftCluster(ctx context.Context, leaderInfos []*raft.LeaderJo
 				challenge:           eBlob,
 				leaderClient:        apiClient,
 				leaderBarrierConfig: &sealConfig,
-				nonVoter:            nonVoter,
+				readReplica:         readReplica,
 			}
 
 			// If we're using Shamir and using raft for both physical and HA, we
@@ -1077,7 +1077,7 @@ func (c *Core) joinRaftSendAnswer(ctx context.Context, sealAccess *seal.Access,
 		"answer":       base64.StdEncoding.EncodeToString(plaintext),
 		"cluster_addr": clusterAddr,
 		"server_id":    raftBackend.NodeID(),
-		"non_voter":    raftInfo.nonVoter,
+		"read_replica": raftInfo.readReplica,
 	}); err != nil {
 		return err
 	}

website/content/api-docs/system/storage/raft.mdx

@@ -39,6 +39,19 @@ leader node.
 - `leader_client_key` `(string: "")` - Client key used to communicate with
   Raft's leader node.
 
+- `auto_join` `(string: "")` - Defines any cloud auto-join metadata. If
+ supplied, Vault will attempt to automatically discover peers in addition to what
+ can be provided via 'leader_api_addr'.
+
+- `auto_join_scheme` `(string: "https")` - URI scheme to be used for `auto_join`.
+
+- `auto_join_port` `(int: 8200)` - Port to be used for `auto_join`.
+
+- `-read-replica` `(bool: false) (enterprise)` - This flag is used to make the
+  server not participate in the Raft quorum, and have it only receive the data
+  replication stream. This can be used to add read scalability to a cluster in
+  cases where a high volume of reads to servers are needed. The default is false.
+
 ### Sample Payload
 
 ```json