具体出错信息如下：
[root@blockstorage ~]# rabbitmqctl change_password guest RABBIT_PASS
Changing password for user "guest" ...
Error: unable to connect to node rabbit@blockstorage: nodedown DIAGNOSTICS
=========== nodes in question: [rabbit@blockstorage] hosts, their running nodes and ports:
- unable to connect to epmd on blockstorage: timeout (timed out) current node details:
- node name: rabbitmqctl2309@blockstorage
- home dir: /var/lib/rabbitmq
- cookie hash: 9MAewQpNA2Hn9l2WPQ++rw==
解决方案：在/etc/hosts文件中加入一行“127.0.0.1 主机名”即可，加入IP地址和主机名是不行的。
[root@blockstorage ~]# vi /etc/hosts 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
:: localhost localhost.localdomain localhost6 localhost6.localdomain6
127.0.0.1 blockstorage
192.168. blockstorage
然后，启动查看状态皆OK
[root@blockstorage ~]# systemctl start rabbitmq-server.service
[root@blockstorage ~]# rabbitmqctl status
Status of node rabbit@blockstorage ...
[{pid,},
{running_applications,[{rabbit,"RabbitMQ","3.1.5"},
{mnesia,"MNESIA CXC 138 12","4.11"},
{os_mon,"CPO CXC 138 46","2.2.14"},
{xmerl,"XML parser","1.3.6"},
{sasl,"SASL CXC 138 11","2.3.4"},
{stdlib,"ERTS CXC 138 10","1.19.4"},
{kernel,"ERTS CXC 138 10","2.16.4"}]},
{os,{unix,linux}},
{erlang_version,"Erlang R16B03-1 (erts-5.10.4) [source] [64-bit] [smp:2:2] [async-threads:30] [hipe] [kernel-poll:true]\n"},
{memory,[{total,},
{connection_procs,},
{queue_procs,},
{plugins,},
{other_proc,},
{mnesia,},
{mgmt_db,},
{msg_index,},
{other_ets,},
{binary,},
{code,},
{atom,},
{other_system,}]},
{vm_memory_high_watermark,0.4},
{vm_memory_limit,},
{disk_free_limit,},
{disk_free,},
{file_descriptors,[{total_limit,},
{total_used,},
{sockets_limit,},
{sockets_used,}]},
{processes,[{limit,},{used,}]},
{run_queue,},
{uptime,}]
...done.
[root@blockstorage ~]#