diff --git a/src/resource_pool.go b/src/resource_pool.go
index dc9c554..56babb4 100644
--- a/src/resource_pool.go
+++ b/src/resource_pool.go
@@ -16,6 +16,7 @@ type ResourcePool struct {
 
 func (pool *ResourcePool) start() {
 	/* check dead nodes */
+	pool.heartBeat = map[string]time.Time{}
 	for k, v := range pool.heartBeat {
 		if v.Add(time.Second * 30).Before(time.Now()) {
 			delete(pool.nodes, k)