diff --git a/pkg/discoveryregistry/zookeeper/zk.go b/pkg/discoveryregistry/zookeeper/zk.go
index 423d0b6c1..686165b40 100644
--- a/pkg/discoveryregistry/zookeeper/zk.go
+++ b/pkg/discoveryregistry/zookeeper/zk.go
@@ -91,6 +91,7 @@ func NewClient(zkServers []string, zkRoot string, options ...ZkOption) (*ZkClien
 		timeout:    timeout,
 		localConns: make(map[string][]resolver.Address),
 		resolvers:  make(map[string]*Resolver),
+		lock:       &sync.Mutex{},
 	}
 	client.ticker = time.NewTicker(defaultFreq)
 	for _, option := range options {