kafka拒绝连接zookeeper

kafka连接zookeeper时报错：

FATAL Fatal error during KafkaServer startup. Prepare to shutdown (kafka.server.KafkaServer)
org.I0Itec.zkclient.exception.ZkTimeoutException: Unable to connect to zookeeper server 'localhost:2181' with timeout of 6000 ms

请问如何解决？