fix(scheduler): remove node from cache when node-selector label is removed

When using --node-selector in volcano scheduler, removing the matching
label from a node did not evict the node from the scheduler cache.
SyncNode() checked nodeCanAddCache() but only returned nil without
calling RemoveNode(), causing the scheduler to continue scheduling
pods to nodes that no longer match the selector.

Add RemoveNode() call when nodeCanAddCache() returns false, so the
node is properly evicted from cache when its labels no longer match
the configured node selector.

Signed-off-by: brick-pixel <brick-pixel@users.noreply.github.com>

Author: brick-pixel

pkg/scheduler/cache/event_handlers.go

@@ -621,6 +621,11 @@ func (sc *SchedulerCache) SyncNode(nodeName string) error {
 	}
 
 	if !sc.nodeCanAddCache(node) {
+		if deleteErr := sc.RemoveNode(nodeName); deleteErr != nil {
+			klog.Errorf("Failed to remove node <%s> from cache after label change: %s", nodeName, deleteErr.Error())
+			return deleteErr
+		}
+		klog.V(3).Infof("Node <%s> no longer matches node selector, removed from cache.", nodeName)
 		return nil
 	}
 	nodeCopy := node.DeepCopy()

pkg/scheduler/cache/event_handlers_test.go

@@ -1573,3 +1573,26 @@ func TestSchedulerCache_SyncHyperNode(t *testing.T) {
 		})
 	}
 }
+
+func TestSchedulerCache_SyncNode_RemoveOnLabelChange(t *testing.T) {
+	// Simulate: node was in cache with matching label, then label is removed
+	n1WithLabel := util.BuildNode("n1", nil, map[string]string{"train": "true"})
+	n1WithoutLabel := util.BuildNode("n1", nil, map[string]string{})
+
+	sc := NewDefaultMockSchedulerCache("volcano")
+	sc.nodeSelectorLabels = map[string]sets.Empty{
+		"train:true": {},
+	}
+
+	// Step 1: Add node with matching label to cache
+	sc.nodeInformer.Informer().GetIndexer().Add(n1WithLabel)
+	err := sc.SyncNode("n1")
+	assert.NoError(t, err)
+	assert.Contains(t, sc.Nodes, "n1", "node should be in cache after sync with matching label")
+
+	// Step 2: Update node to remove the label, then sync again
+	sc.nodeInformer.Informer().GetIndexer().Update(n1WithoutLabel)
+	err = sc.SyncNode("n1")
+	assert.NoError(t, err)
+	assert.NotContains(t, sc.Nodes, "n1", "node should be removed from cache after label removal")
+}