Client port found: 2181. Client address: localhost. Error contacting service. It is probably not running

问题：
异常信息：启动zookeeper时提示Starting zookeeper … already running as process 2502.
使用命令./zkServer.sh status查看状态显示ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/bin/…/conf/zoo.cfg
Client port found: 2181. Client address: localhost.
Error contacting service. It is probably not running.
通过浏览conf中zoo.cfg文件发现配置没问题。

解决办法1：通过命令进入cd /usr/local/zookeeper/data中找到zookeeper_server.pid文件进行删除，然后重新启动zookeeper即可

解决办法2：关闭防火墙，systemctl stop firewalld.service，重启zookeeper。