rabbit无法启动，Job for rabbitmq-server.service failed because a timeout was exceeded

[root@rabbitmq02 ~]# service rabbitmq-server   start
Redirecting to /bin/systemctl start rabbitmq-server.service
Job for rabbitmq-server.service failed because a timeout was exceeded. See "systemctl status rabbitmq-server.service" and "journalctl -xe" for details.
[root@rabbitmq02 ~]# 

发生这样的问题，有两种解决方案，第一种，删除

/var/lib/rabbitmq/mnesia 目录下所有文件及文件夹

可以看启动日志,cd /var/log/rabbitmq

还有一种可能是，搭建了集群，这个原因是要先启动从节点，再启动从节点！！！！

最后启动主节点