Add minimum active size and promote delay.

server/cluster_config.go

@@ -8,8 +8,14 @@ const (
 	// DefaultActiveSize is the default number of active followers allowed.
 	DefaultActiveSize = 9
 
+	// MinActiveSize is the minimum active size allowed.
+	MinActiveSize = 3
+
 	// DefaultPromoteDelay is the default elapsed time before promotion.
 	DefaultPromoteDelay = int((30 * time.Minute) / time.Second)
+
+	// MinPromoteDelay is the minimum promote delay allowed.
+	MinPromoteDelay = int((2 * time.Second) / time.Second)
 )
 
 // ClusterConfig represents cluster-wide configuration settings.

server/peer_server.go

@@ -158,17 +158,16 @@ func (s *PeerServer) ClusterConfig() *ClusterConfig {
 // SetClusterConfig updates the current cluster configuration.
 // Adjusting the active size will cause the PeerServer to demote peers or
 // promote proxies to match the new size.
-func (s *PeerServer) SetClusterConfig(c *ClusterConfig) error {
-	// Validate configuration.
-	if c.ActiveSize < 1 {
-		return etcdErr.NewError(etcdErr.EcodeInvalidActiveSize, "Post", 0)
-	} else if c.PromoteDelay < 0 {
-		return etcdErr.NewError(etcdErr.EcodeInvalidPromoteDelay, "Post", 0)
+func (s *PeerServer) SetClusterConfig(c *ClusterConfig) {
+	// Set minimums.
+	if c.ActiveSize < MinActiveSize {
+		c.ActiveSize = MinActiveSize
+	}
+	if c.PromoteDelay < MinPromoteDelay {
+		c.PromoteDelay = MinPromoteDelay
 	}
 
 	s.clusterConfig = c
-
-	return nil
 }
 
 // Helper function to do discovery and return results in expected format

server/set_cluster_config_command.go

@@ -21,5 +21,6 @@ func (c *SetClusterConfigCommand) CommandName() string {
 // Apply updates the cluster configuration.
 func (c *SetClusterConfigCommand) Apply(context raft.Context) (interface{}, error) {
 	ps, _ := context.Server().Context().(*PeerServer)
-	return nil, ps.SetClusterConfig(c.Config)
+	ps.SetClusterConfig(c.Config)
+	return nil, nil
 }