diff --git a/internal/datacoord/cluster.go b/internal/datacoord/cluster.go
index 86bf2042c8..de36366737 100644
--- a/internal/datacoord/cluster.go
+++ b/internal/datacoord/cluster.go
@@ -22,7 +22,6 @@ import (
 
 	"github.com/milvus-io/milvus-proto/go-api/v2/commonpb"
 	"github.com/milvus-io/milvus/internal/log"
-	"github.com/milvus-io/milvus/internal/metrics"
 	"github.com/milvus-io/milvus/internal/proto/datapb"
 	"github.com/milvus-io/milvus/internal/util/commonpbutil"
 	"github.com/samber/lo"
@@ -60,21 +59,13 @@ func (c *Cluster) Startup(ctx context.Context, nodes []*NodeInfo) error {
 // Register registers a new node in cluster
 func (c *Cluster) Register(node *NodeInfo) error {
 	c.sessionManager.AddSession(node)
-	err := c.channelManager.AddNode(node.NodeID)
-	if err == nil {
-		metrics.DataCoordNumDataNodes.WithLabelValues().Inc()
-	}
-	return err
+	return c.channelManager.AddNode(node.NodeID)
 }
 
 // UnRegister removes a node from cluster
 func (c *Cluster) UnRegister(node *NodeInfo) error {
 	c.sessionManager.DeleteSession(node)
-	err := c.channelManager.DeleteNode(node.NodeID)
-	if err == nil {
-		metrics.DataCoordNumDataNodes.WithLabelValues().Dec()
-	}
-	return err
+	return c.channelManager.DeleteNode(node.NodeID)
 }
 
 // Watch tries to add a channel in datanode cluster
diff --git a/internal/datacoord/session_manager.go b/internal/datacoord/session_manager.go
index 32b06efe95..fa13ea3a50 100644
--- a/internal/datacoord/session_manager.go
+++ b/internal/datacoord/session_manager.go
@@ -25,6 +25,7 @@ import (
 	"github.com/milvus-io/milvus-proto/go-api/v2/commonpb"
 	grpcdatanodeclient "github.com/milvus-io/milvus/internal/distributed/datanode/client"
 	"github.com/milvus-io/milvus/internal/log"
+	"github.com/milvus-io/milvus/internal/metrics"
 	"github.com/milvus-io/milvus/internal/proto/datapb"
 	"github.com/milvus-io/milvus/internal/types"
 	"github.com/milvus-io/milvus/internal/util/commonpbutil"
@@ -83,6 +84,7 @@ func (c *SessionManager) AddSession(node *NodeInfo) {
 
 	session := NewSession(node, c.sessionCreator)
 	c.sessions.data[node.NodeID] = session
+	metrics.DataCoordNumDataNodes.WithLabelValues().Set(float64(len(c.sessions.data)))
 }
 
 // DeleteSession removes the node session
@@ -94,6 +96,7 @@ func (c *SessionManager) DeleteSession(node *NodeInfo) {
 		session.Dispose()
 		delete(c.sessions.data, node.NodeID)
 	}
+	metrics.DataCoordNumDataNodes.WithLabelValues().Set(float64(len(c.sessions.data)))
 }
 
 // getLiveNodeIDs returns IDs of all live DataNodes.
diff --git a/internal/indexcoord/node_manager.go b/internal/indexcoord/node_manager.go
index 5969d1abbd..f31eabd1a7 100644
--- a/internal/indexcoord/node_manager.go
+++ b/internal/indexcoord/node_manager.go
@@ -65,6 +65,7 @@ func (nm *NodeManager) setClient(nodeID UniqueID, client types.IndexNode) {
 	}
 	nm.lock.Lock()
 	nm.nodeClients[nodeID] = client
+	metrics.IndexCoordIndexNodeNum.WithLabelValues().Set(float64(len(nm.nodeClients)))
 	log.Info("IndexNode NodeManager setClient success", zap.Int64("nodeID", nodeID), zap.Int("IndexNode num", len(nm.nodeClients)))
 	nm.lock.Unlock()
 	nm.pq.Push(item)
@@ -75,10 +76,10 @@ func (nm *NodeManager) RemoveNode(nodeID UniqueID) {
 	log.Info("IndexCoord", zap.Any("Remove node with ID", nodeID))
 	nm.lock.Lock()
 	delete(nm.nodeClients, nodeID)
+	metrics.IndexCoordIndexNodeNum.WithLabelValues().Set(float64(len(nm.nodeClients)))
 	delete(nm.stoppingNodes, nodeID)
 	nm.lock.Unlock()
 	nm.pq.Remove(nodeID)
-	metrics.IndexCoordIndexNodeNum.WithLabelValues().Dec()
 }
 
 func (nm *NodeManager) StoppingNode(nodeID UniqueID) {
@@ -112,7 +113,6 @@ func (nm *NodeManager) AddNode(nodeID UniqueID, address string) error {
 		log.Error("IndexCoord NodeManager", zap.Any("Add node err", err))
 		return err
 	}
-	metrics.IndexCoordIndexNodeNum.WithLabelValues().Inc()
 	nm.setClient(nodeID, nodeClient)
 	return nil
 }