Add non-voting nodes to cluster

This allows users to add non-voting nodes to cluster at cluster start or join time by setting a boolean flag. Signed-off-by: Alexander Scheel <[email protected]>
openbao · Nov 23, 2024 · 45ed244 · 45ed244
1 parent 6d78ab5
commit 45ed244
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Showing 4 changed files with 43 additions and 6 deletions.
diff --git a/cmd/devbao/cluster_join.go b/cmd/devbao/cluster_join.go
@@ -16,9 +16,16 @@ func BuildClusterJoinCommand() *cli.Command {
 		Usage:     "join a given node to the cluster",
 
 		Action: RunClusterJoinCommand,
-	}
 
-	c.Flags = append(c.Flags, ClusterFlags()...)
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:    "non-voter",
+				Aliases: []string{"nv"},
+				Value:   false,
+				Usage:   "mark new node as a non-voter",
+			},
+		},
+	}
 
 	return c
 }
@@ -31,6 +38,8 @@ func RunClusterJoinCommand(cCtx *cli.Context) error {
 	clusterName := cCtx.Args().First()
 	nodeName := cCtx.Args().Get(1)
 
+	nonVoter := cCtx.Bool("non-voter")
+
 	cluster, err := bao.LoadCluster(clusterName)
 	if err != nil {
 		return fmt.Errorf("error loading cluster: %w", err)
@@ -45,6 +54,8 @@ func RunClusterJoinCommand(cCtx *cli.Context) error {
 		return fmt.Errorf("refusing to add node already in a cluster (`%v`)", node.Cluster)
 	}
 
+	node.NonVoter = nonVoter
+
 	if err := cluster.JoinNodeHACluster(node); err != nil {
 		return fmt.Errorf("failed to join node to cluster: %w", err)
 	}

diff --git a/cmd/devbao/cluster_start.go b/cmd/devbao/cluster_start.go
@@ -29,6 +29,11 @@ func ClusterInfoFlags() []cli.Flag {
 			Value: 3,
 			Usage: "number of nodes to run in the cluster; suggested to use an odd number.",
 		},
+		&cli.IntFlag{
+			Name:  "non-voter",
+			Value: 0,
+			Usage: "number of non-voter nodes to run in the cluster; less than count",
+		},
 		&cli.StringFlag{
 			Name:  "listen",
 			Value: "0.0.0.0",
@@ -85,11 +90,16 @@ func RunClusterStartCommand(cCtx *cli.Context) error {
 
 	listen := cCtx.String("listen")
 
+	nonVoter := cCtx.Int("non-voter")
+	if nonVoter < 0 {
+		return fmt.Errorf("expected at least zero non-voter nodes; got %v", nonVoter)
+	}
+
 	count := cCtx.Int("count")
 	if count < 1 {
 		return fmt.Errorf("required to have at least one node in the cluster; got %v", count)
-	} else if (count % 2) == 0 {
-		fmt.Fprintf(os.Stderr, "[warning] it is suggested to have an odd number of nodes in the HA cluster")
+	} else if ((count - nonVoter) % 2) == 0 {
+		fmt.Fprintf(os.Stderr, "[warning] it is suggested to have an odd number of voting nodes in the HA cluster")
 	}
 
 	clusterName := cCtx.Args().First()
@@ -110,7 +120,14 @@ func RunClusterStartCommand(cCtx *cli.Context) error {
 	// Build nodes
 	var nodes []*bao.Node
 	for index := 0; index < count; index++ {
-		name := fmt.Sprintf("%v-node-%d", clusterName, index)
+		nonVoter := index >= (count - nonVoter)
+
+		nvSuffix := ""
+		if nonVoter {
+			nvSuffix = "-nv"
+		}
+
+		name := fmt.Sprintf("%v-node-%d%v", clusterName, index, nvSuffix)
 		fmt.Printf("starting %v...\n", name)
 
 		port := portBase + index*100
@@ -159,6 +176,13 @@ func RunClusterStartCommand(cCtx *cli.Context) error {
 			return fmt.Errorf("failed to build node %v: %w", name, err)
 		}
 
+		node.NonVoter = nonVoter
+		if nonVoter {
+			if err := node.SaveConfig(); err != nil {
+				return fmt.Errorf("failed to save non-voter config for node %v: %w", name, err)
+			}
+		}
+
 		if err := node.Start(); err != nil {
 			return fmt.Errorf("failed to start node %v: %w", name, err)
 		}

diff --git a/pkg/bao/cluster.go b/pkg/bao/cluster.go
@@ -286,6 +286,7 @@ func (c *Cluster) JoinNodeHACluster(node *Node) error {
 	resp, err := nodeClient.Sys().RaftJoin(&api.RaftJoinRequest{
 		LeaderAPIAddr: leaderClient.Address(),
 		Retry:         true,
+		NonVoter:      node.NonVoter,
 	})
 	if err != nil {
 		return fmt.Errorf("failed joining node %v to cluster %v / leader %v: %w", node.Name, c.Name, leaderNode.Name, err)

diff --git a/pkg/bao/node.go b/pkg/bao/node.go
@@ -30,7 +30,8 @@ type Node struct {
 	Token      string   `json:"token"`
 	UnsealKeys []string `json:"unseal_keys,omitempty"`
 
-	Cluster string `json:"cluster,omitempty"`
+	Cluster  string `json:"cluster,omitempty"`
+	NonVoter bool   `json:"non_voter"`
 }
 
 func (n *Node) FromInterface(iface map[string]interface{}) error {