cloudera manager agent 报错

[02/Nov/2017 10:39:11 +0000] 16104 MainThread agent        ERROR    Heartbeating to 10.0.21.236:7182 failed.
Traceback (most recent call last):
  File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/cmf-5.12.1-py2.7.egg/cmf/agent.py", line 1412, in _send_heartbeat
    self.master_port)
  File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/avro-1.6.3-py2.7.egg/avro/ipc.py", line 469, in __init__
    self.conn.connect()
  File "/usr/lib64/python2.7/httplib.py", line 772, in connect
    self.timeout, self.source_address)
  File "/usr/lib64/python2.7/socket.py", line 571, in create_connection
    raise err
error: [Errno 111] Connection refused
web页面无法打开，求解决

[02/Nov/2017 10:39:11 +0000] 16104 MainThread agent        ERROR    Heartbeating to 10.0.21.236:7182 failed.
心跳失败，被拒绝。显然是网络的问题。先看看7182端口是否是通的。
可参考：
大数据集群【hadoop、hbase、spark、hive，zookeeper、storm等】故障排除之端口详解
http://www.aboutyun.com/forum.php?mod=viewthread&tid=20880